Updated version

(cherry picked from commit e78ab81b26)

.editorconfig

@@ -63,7 +63,7 @@ dotnet_diagnostic.IDE0161.severity = warning
 
 # IDE0200 Remove unnecessary lambda expression
 #csharp_style_prefer_method_group_conversion = true
-dotnet_diagnostic.IDE0200.severity = warning
+dotnet_diagnostic.IDE0200.severity = silent # Requires C# 11
 
 # IDE0210 Convert to top-level statements/IDE0211 Convert to 'Program.Main' style program
 csharp_style_prefer_top_level_statements = false
@@ -72,7 +72,7 @@ dotnet_diagnostic.IDE0211.severity = warning
 
 # IDE0290 Use primary constructor
 #csharp_style_prefer_primary_constructors = true
-dotnet_diagnostic.IDE0290.severity = silent
+dotnet_diagnostic.IDE0200.severity = silent # Requires C# 12
 
 # IDE0330 Prefer 'System.Threading.Lock'
 #csharp_prefer_system_threading_lock = true
@@ -229,10 +229,6 @@ dotnet_diagnostic.IDE0100.severity = warning
 # No options
 dotnet_diagnostic.IDE0120.severity = warning
 
-# IDE0121 Simplify LINQ type check and cast
-# No options
-dotnet_diagnostic.IDE0121.severity = warning
-
 # IDE0130 Namespace does not match folder structure
 #dotnet_style_namespace_match_folder = true
 # This rule doesn't appear to work (never reports violations)
@@ -296,7 +292,7 @@ dotnet_diagnostic.IDE0220.severity = warning
 
 # IDE0230 Use UTF-8 string literal
 #csharp_style_prefer_utf8_string_literals = true
-dotnet_diagnostic.IDE0230.severity = warning
+dotnet_diagnostic.IDE0230.severity = silent # Requires C# 11
 
 # IDE0240 Nullable directive is redundant
 # No options
@@ -312,43 +308,27 @@ dotnet_diagnostic.IDE0241.severity = warning
 
 # IDE0300 Use collection expression for array
 # From above, uses dotnet_style_prefer_collection_expression
-dotnet_diagnostic.IDE0300.severity = warning
+dotnet_diagnostic.IDE0300.severity = silent # Requires C# 12
 
 # IDE0301 Use collection expression for empty
 # From above, uses dotnet_style_prefer_collection_expression
-dotnet_diagnostic.IDE0301.severity = warning
+dotnet_diagnostic.IDE0301.severity = silent # Requires C# 12
 
 # IDE0302 Use collection expression for stackalloc
 # From above, uses dotnet_style_prefer_collection_expression
-dotnet_diagnostic.IDE0302.severity = warning
+dotnet_diagnostic.IDE0302.severity = silent # Requires C# 12
 
 # IDE0303 Use collection expression for 'Create()'
 # From above, uses dotnet_style_prefer_collection_expression
-dotnet_diagnostic.IDE0303.severity = warning
+dotnet_diagnostic.IDE0303.severity = silent # Requires C# 12
 
 # IDE0304 Use collection expression for builder
 # From above, uses dotnet_style_prefer_collection_expression
-dotnet_diagnostic.IDE0304.severity = warning
+dotnet_diagnostic.IDE0304.severity = silent # Requires C# 12
 
 # IDE0305 Use collection expression for fluent
 # From above, uses dotnet_style_prefer_collection_expression
-dotnet_diagnostic.IDE0305.severity = silent
-
-# IDE0306 Use collection expression for new
-# From above, uses dotnet_style_prefer_collection_expression
-dotnet_diagnostic.IDE0306.severity = warning
-
-# IDE0340 Use unbound generic type
-#csharp_style_prefer_unbound_generic_type_in_nameof = true
-dotnet_diagnostic.IDE0340.severity = silent # Requires C# 14
-
-# IDE0350 Use implicitly typed lambda
-#csharp_style_prefer_implicitly_typed_lambda_expression = true
-dotnet_diagnostic.IDE0350.severity = warning
-
-# IDE0360 Simplify property accessor
-#csharp_style_prefer_simple_property_accessors = true
-dotnet_diagnostic.IDE0360.severity = silent # Requires C# 13
+dotnet_diagnostic.IDE0305.severity = silent # Requires C# 12
 
 ## Field preferences
 
@@ -393,10 +373,6 @@ dotnet_diagnostic.IDE0251.severity = warning
 #csharp_prefer_static_anonymous_function = true
 dotnet_diagnostic.IDE0320.severity = warning
 
-# IDE0380 Remove unnecessary 'unsafe' modifier
-# No options
-dotnet_diagnostic.IDE0380.severity = warning
-
 ## Null-checking preferences
 
 # IDE1005 Use conditional delegate call
@@ -411,7 +387,7 @@ dotnet_diagnostic.IDE0060.severity = warning
 
 # IDE0280 Use 'nameof'
 # No options
-dotnet_diagnostic.IDE0280.severity = warning
+dotnet_diagnostic.IDE0280.severity = silent # Requires C# 11
 
 ## Parentheses preferences
 
@@ -450,7 +426,7 @@ dotnet_diagnostic.IDE0083.severity = warning
 
 # IDE0170 Simplify property pattern
 #csharp_style_prefer_extended_property_pattern = true
-dotnet_diagnostic.IDE0170.severity = warning
+dotnet_diagnostic.IDE0170.severity = silent # Requires C# 10
 
 ## Suppression preferences
 
@@ -458,10 +434,6 @@ dotnet_diagnostic.IDE0170.severity = warning
 #dotnet_remove_unnecessary_suppression_exclusions = none
 dotnet_diagnostic.IDE0079.severity = warning
 
-# IDE0370 Remove unnecessary suppression (null-forgiving operator)
-# No options
-dotnet_diagnostic.IDE0370.severity = warning
-
 ## 'this' and 'Me' preferences
 
 # IDE0003/IDE0009 Remove 'this' or 'Me' qualification/Add 'this' or 'Me' qualification
@@ -776,7 +748,7 @@ dotnet_diagnostic.CA1305.severity = warning
 dotnet_diagnostic.CA1310.severity = warning
 
 # Specify a culture or use an invariant version.
-dotnet_diagnostic.CA1311.severity = warning
+dotnet_diagnostic.CA1311.severity = suggestion # TODO: Change to warning once using .NET 7 or later.
 
 ### Portability and Interoperability Rules
 ### https://learn.microsoft.com/en-us/dotnet/fundamentals/code-analysis/quality-rules/interoperability-warnings
@@ -791,25 +763,19 @@ dotnet_diagnostic.CA1417.severity = warning
 dotnet_diagnostic.CA1507.severity = warning
 
 # Use ArgumentNullException throw helper.
-dotnet_diagnostic.CA1510.severity = warning
+dotnet_diagnostic.CA1510.severity = suggestion # TODO: Change to warning once using .NET 7 or later.
 
 # Use ArgumentException throw helper.
-dotnet_diagnostic.CA1511.severity = warning
+dotnet_diagnostic.CA1511.severity = suggestion # TODO: Change to warning once using .NET 7 or later.
 
 # Use ArgumentOutOfRangeException throw helper.
-dotnet_diagnostic.CA1512.severity = warning
+dotnet_diagnostic.CA1512.severity = suggestion # TODO: Change to warning once using .NET 8 or later.
 
 # Use ObjectDisposedException throw helper.
-dotnet_diagnostic.CA1513.severity = warning
+dotnet_diagnostic.CA1513.severity = suggestion # TODO: Change to warning once using .NET 7 or later.
 
 # Avoid redundant length argument.
-dotnet_diagnostic.CA1514.severity = warning
-
-# Consider making public types internal.
-dotnet_diagnostic.CA1515.severity = warning
-
-# Use cross-platform intrinsics.
-dotnet_diagnostic.CA1516.severity = warning
+dotnet_diagnostic.CA1514.severity = suggestion # TODO: Change to warning once using .NET 8 or later.
 
 ### Naming Rules
 ### https://learn.microsoft.com/en-us/dotnet/fundamentals/code-analysis/quality-rules/naming-warnings
@@ -902,8 +868,8 @@ dotnet_diagnostic.CA1843.severity = warning
 # Provide memory-based overrides of async methods when subclassing 'Stream'.
 dotnet_diagnostic.CA1844.severity = warning
 
-# Use span-based 'string.Concat'.
-dotnet_diagnostic.CA1845.severity = warning
+# Use span-based 'string.Concat'. (Not available on mono)
+dotnet_diagnostic.CA1845.severity = none
 
 # Prefer AsSpan over Substring.
 dotnet_diagnostic.CA1846.severity = warning
@@ -912,34 +878,34 @@ dotnet_diagnostic.CA1846.severity = warning
 dotnet_diagnostic.CA1847.severity = warning
 
 # Call async methods when in an async method.
-dotnet_diagnostic.CA1849.severity = warning
+dotnet_diagnostic.CA1849.severity = suggestion # TODO: Change to warning once using .NET 7 or later.
 
-# Prefer static HashData method over ComputeHash.
-dotnet_diagnostic.CA1850.severity = warning
+# Prefer static HashData method over ComputeHash. (Not available on mono)
+dotnet_diagnostic.CA1850.severity = none # TODO: Change to warning once using .NET 7 or later AND once supported by mono.
 
 # Possible multiple enumerations of IEnumerable collection.
 #dotnet_code_quality.CA1851.enumeration_methods =
 dotnet_code_quality.CA1851.linq_chain_methods = M:OpenRA.Traits.IRenderModifier.Modify*
 dotnet_code_quality.CA1851.assume_method_enumerates_parameters = true
-dotnet_diagnostic.CA1851.severity = warning
+dotnet_diagnostic.CA1851.severity = suggestion # TODO: Change to warning once using .NET 7 or later.
 
 # Seal internal types.
-dotnet_diagnostic.CA1852.severity = warning
+dotnet_diagnostic.CA1852.severity = suggestion # TODO: Change to warning once using .NET 7 or later.
 
 # Unnecessary call to 'Dictionary.ContainsKey(key)'.
-dotnet_diagnostic.CA1853.severity = warning
+dotnet_diagnostic.CA1853.severity = suggestion # TODO: Change to warning once using .NET 7 or later.
 
 # Prefer the IDictionary.TryGetValue(TKey, out TValue) method.
-dotnet_diagnostic.CA1854.severity = warning
+dotnet_diagnostic.CA1854.severity = suggestion # TODO: Change to warning once using .NET 7 or later.
 
 # Use Span<T>.Clear() instead of Span<T>.Fill().
-dotnet_diagnostic.CA1855.severity = warning
+dotnet_diagnostic.CA1855.severity = suggestion # TODO: Change to warning once using .NET 7 or later.
 
 # Incorrect usage of ConstantExpected attribute.
-dotnet_diagnostic.CA1856.severity = warning
+dotnet_diagnostic.CA1856.severity = suggestion # TODO: Change to warning once using .NET 7 or later.
 
 # The parameter expects a constant for optimal performance.
-dotnet_diagnostic.CA1857.severity = warning
+dotnet_diagnostic.CA1857.severity = suggestion # TODO: Change to warning once using .NET 7 or later.
 
 # Use StartsWith instead of IndexOf.
 dotnet_diagnostic.CA1858.severity = warning
@@ -951,24 +917,24 @@ dotnet_diagnostic.CA1860.severity = warning
 dotnet_diagnostic.CA1862.severity = warning
 
 # Use 'CompositeFormat'.
-dotnet_diagnostic.CA1863.severity = warning
+dotnet_diagnostic.CA1863.severity = suggestion # TODO: Change to warning once using .NET 7 or later.
 
 # Prefer the 'IDictionary.TryAdd(TKey, TValue)' method.
-dotnet_diagnostic.CA1864.severity = warning
+dotnet_diagnostic.CA1864.severity = suggestion # TODO: Change to warning once using .NET 8 or later.
 
 # Use 'string.Method(char)' instead of 'string.Method(string)' for string with single char.
-dotnet_diagnostic.CA1865.severity = warning
-dotnet_diagnostic.CA1866.severity = warning
-dotnet_diagnostic.CA1867.severity = warning
+dotnet_diagnostic.CA1865.severity = suggestion # TODO: Change to warning once using .NET 8 or later.
+dotnet_diagnostic.CA1866.severity = suggestion # TODO: Change to warning once using .NET 8 or later.
+dotnet_diagnostic.CA1867.severity = suggestion # TODO: Change to warning once using .NET 8 or later.
 
 # Unnecessary call to 'Contains' for sets.
-dotnet_diagnostic.CA1868.severity = warning
+dotnet_diagnostic.CA1868.severity = suggestion # TODO: Change to warning once using .NET 8 or later.
 
 # Cache and reuse 'JsonSerializerOptions' instances.
-dotnet_diagnostic.CA1869.severity = warning
+dotnet_diagnostic.CA1869.severity = suggestion # TODO: Change to warning once using .NET 8 or later.
 
 # Use a cached 'SearchValues' instance.
-dotnet_diagnostic.CA1870.severity = warning
+dotnet_diagnostic.CA1870.severity = suggestion # TODO: Change to warning once using .NET 8 or later.
 
 # Do not pass a nullable struct to 'ArgumentNullException.ThrowIfNull'.
 dotnet_diagnostic.CA1871.severity = warning
@@ -976,18 +942,6 @@ dotnet_diagnostic.CA1871.severity = warning
 # Prefer 'Convert.ToHexString' and 'Convert.ToHexStringLower' over call chains based on 'BitConverter.ToString'.
 dotnet_diagnostic.CA1872.severity = warning
 
-# Avoid potentially expensive logging.
-dotnet_diagnostic.CA1873.severity = warning
-
-# Use 'Regex.IsMatch'.
-dotnet_diagnostic.CA1874.severity = warning
-
-# Use Use 'Regex.Count'.
-dotnet_diagnostic.CA1875.severity = warning
-
-# Use 'Path.Combine' or 'Path.Join' overloads.
-dotnet_diagnostic.CA1877.severity = warning
-
 ### Reliability Rules
 ### https://learn.microsoft.com/en-us/dotnet/fundamentals/code-analysis/quality-rules/reliability-warnings
 
@@ -1010,7 +964,7 @@ dotnet_diagnostic.CA2016.severity = warning
 dotnet_diagnostic.CA2018.severity = warning
 
 # ThreadStatic fields should not use inline initialization.
-dotnet_diagnostic.CA2019.severity = warning
+dotnet_diagnostic.CA2019.severity = suggestion # TODO: Change to warning once using .NET 7 or later.
 
 # Don't call Enumerable.Cast<T> or Enumerable.OfType<T> with incompatible types.
 dotnet_diagnostic.CA2021.severity = warning
@@ -1018,18 +972,6 @@ dotnet_diagnostic.CA2021.severity = warning
 # Avoid inexact read with Stream.Read.
 dotnet_diagnostic.CA2022.severity = warning
 
-# Invalid braces in message template.
-dotnet_diagnostic.CA2023.severity = warning
-
-# Do not use StreamReader.EndOfStream in async methods.
-dotnet_diagnostic.CA2024.severity = warning
-
-# Do not pass 'IDisposable' instances into unawaited tasks.
-dotnet_diagnostic.CA2025.severity = warning
-
-# Prefer JsonElement.Parse over JsonDocument.Parse().RootElement.
-dotnet_diagnostic.CA2026.severity = warning
-
 ### Security Rules
 ### https://learn.microsoft.com/en-us/dotnet/fundamentals/code-analysis/quality-rules/security-warnings
 
@@ -1099,10 +1041,10 @@ dotnet_diagnostic.CA2250.severity = warning
 dotnet_diagnostic.CA2251.severity = warning
 
 # Ensure ThreadStatic is only used with static fields.
-dotnet_diagnostic.CA2259.severity = warning
+dotnet_diagnostic.CA2259.severity = suggestion # TODO: Change to warning once using .NET 7 or later.
 
 # Prefer generic overload when type is known.
-dotnet_diagnostic.CA2263.severity = warning
+dotnet_diagnostic.CA2263.severity = none # TODO: Change to warning once mono is dropped.
 
 # Do not pass a non-nullable value to 'ArgumentNullException.ThrowIfNull'.
 dotnet_diagnostic.CA2264.severity = warning
@@ -1318,24 +1260,3 @@ dotnet_diagnostic.RCS1239.severity = warning
 
 # Use element access.
 dotnet_diagnostic.RCS1246.severity = warning
-
-# Use enum field explicitly.
-dotnet_diagnostic.RCS1257.severity = warning
-
-# Unnecessary enum flag.
-dotnet_diagnostic.RCS1258.severity = warning
-
-# Resource can be disposed asynchronously.
-dotnet_diagnostic.RCS1261.severity = warning
-
-# Unnecessary raw string literal.
-dotnet_diagnostic.RCS1262.severity = warning
-
-# Remove redundant catch block.
-dotnet_diagnostic.RCS1265.severity = warning
-
-# Use raw string literal.
-dotnet_diagnostic.RCS1266.severity = warning
-
-# Use string interpolation instead of 'string.Concat'.
-dotnet_diagnostic.RCS1267.severity = warning

.github/ISSUE_TEMPLATE/crash-report.md

@@ -16,6 +16,7 @@ assignees: ''
 - OpenRA Version: ENGINE VERSION
 - OpenRA Mod: GAME MOD
 - Source: Official download package OR self-compiled OR third-party package
+- For self-compiled or third-party packages: Mono version
 
 
 ## Exception log

.github/dependabot.yml

@@ -1,6 +0,0 @@
-version: 2
-updates:
-- package-ecosystem: github-actions
-  directory: "/"
-  schedule:
-    interval: daily

.github/workflows/ci.yml

@@ -2,30 +2,28 @@ name: Continuous Integration
 
 on:
   push:
-    paths-ignore:
-      - '*.md'
   pull_request:
     branches: [ bleed, 'prep-*' ]
-    paths-ignore:
-      - '*.md'
-      - '*.py'
 
 permissions:
   contents: read  #  to fetch code (actions/checkout)
 
 jobs:
   linux:
-    name: Linux (.NET 8.0)
+    name: Linux (.NET 6.0)
     runs-on: ubuntu-22.04
 
     steps:
-      - name: Clone Repository
-        uses: actions/checkout@v6
+      - name: Remove System .NET
+        run: sudo apt-get remove -y dotnet*
 
-      - name: Install .NET 8.0
-        uses: actions/setup-dotnet@v5
+      - name: Clone Repository
+        uses: actions/checkout@v4
+
+      - name: Install .NET 6.0
+        uses: actions/setup-dotnet@v4
         with:
-          dotnet-version: '8.0.x'
+          dotnet-version: '6.0.x'
 
       - name: Check Code
         run: |
@@ -38,18 +36,36 @@ jobs:
           make check-scripts
           make TREAT_WARNINGS_AS_ERRORS=true test
 
-  windows:
-    name: Windows (.NET 8.0)
-    runs-on: windows-2022
+  linux-mono:
+    name: Linux (mono)
+    runs-on: ubuntu-22.04
 
     steps:
       - name: Clone Repository
-        uses: actions/checkout@v6
+        uses: actions/checkout@v4
 
-      - name: Install .NET 8.0
-        uses: actions/setup-dotnet@v5
+      - name: Check Code
+        run: |
+          mono --version
+          make RUNTIME=mono check
+
+      - name: Check Mods
+        run: |
+          # check-scripts does not depend on .net/mono, so is not needed here
+          make RUNTIME=mono TREAT_WARNINGS_AS_ERRORS=true test
+
+  windows:
+    name: Windows (.NET 6.0)
+    runs-on: windows-2019
+
+    steps:
+      - name: Clone Repository
+        uses: actions/checkout@v4
+
+      - name: Install .NET 6.0
+        uses: actions/setup-dotnet@v4
         with:
-          dotnet-version: '8.0.x'
+          dotnet-version: '6.0.x'
 
       - name: Check Code
         shell: powershell
@@ -61,7 +77,7 @@ jobs:
 
       - name: Check Mods
         run: |
-          choco install lua --version 5.1.5.52 --no-progress
+          choco install lua --version 5.1.5.52
           $ENV:Path = $ENV:Path + ";C:\Program Files (x86)\Lua\5.1\"
           $ENV:TREAT_WARNINGS_AS_ERRORS = "true"
           .\make.ps1 check-scripts

.github/workflows/documentation.yml

@@ -52,21 +52,21 @@ jobs:
           echo ${{ needs.prepare.outputs.version_type }}
 
       - name: Clone Repository
-        uses: actions/checkout@v6
+        uses: actions/checkout@v4
         with:
           ref: ${{ needs.prepare.outputs.git_tag }}
 
-      - name: Install .NET 8
-        uses: actions/setup-dotnet@v5
+      - name: Install .NET 6
+        uses: actions/setup-dotnet@v4
         with:
-          dotnet-version: '8.0.x'
+          dotnet-version: '6.0.x'
 
       - name: Prepare Environment
         run: |
           make all
 
       - name: Clone Wiki
-        uses: actions/checkout@v6
+        uses: actions/checkout@v4
         with:
           repository: openra/openra.wiki
           token: ${{ secrets.DOCS_TOKEN }}
@@ -107,14 +107,14 @@ jobs:
           echo ${{ needs.prepare.outputs.version_type }}
 
       - name: Clone Repository
-        uses: actions/checkout@v6
+        uses: actions/checkout@v4
         with:
           ref: ${{ needs.prepare.outputs.git_tag }}
 
-      - name: Install .NET 8
-        uses: actions/setup-dotnet@v5
+      - name: Install .NET 6
+        uses: actions/setup-dotnet@v4
         with:
-          dotnet-version: '8.0.x'
+          dotnet-version: '6.0.x'
 
       - name: Prepare Environment
         run: |
@@ -122,7 +122,7 @@ jobs:
 
       # version_type is release/playtest/bleed - the name of the target branch.
       - name: Clone docs.openra.net
-        uses: actions/checkout@v6
+        uses: actions/checkout@v4
         with:
           repository: openra/docs
           token: ${{ secrets.DOCS_TOKEN }}

.github/workflows/packaging.yml

@@ -16,7 +16,7 @@ jobs:
     runs-on: ubuntu-22.04
     steps:
       - name: Clone Repository
-        uses: actions/checkout@v6
+        uses: actions/checkout@v4
 
       - name: Prepare Environment
         run: echo "GIT_TAG=${GITHUB_REF#refs/tags/}" >> ${GITHUB_ENV}
@@ -40,12 +40,12 @@ jobs:
     runs-on: ubuntu-22.04
     steps:
       - name: Clone Repository
-        uses: actions/checkout@v6
+        uses: actions/checkout@v4
 
-      - name: Install .NET 8.0
-        uses: actions/setup-dotnet@v5
+      - name: Install .NET 6.0
+        uses: actions/setup-dotnet@v4
         with:
-          dotnet-version: '8.0.x'
+          dotnet-version: '6.0.x'
 
       - name: Prepare Environment
         run: echo "GIT_TAG=${GITHUB_REF#refs/tags/}" >> ${GITHUB_ENV}
@@ -65,15 +65,15 @@ jobs:
 
   macos:
     name: macOS Disk Image
-    runs-on: macos-14
+    runs-on: macos-13
     steps:
       - name: Clone Repository
-        uses: actions/checkout@v6
+        uses: actions/checkout@v4
 
-      - name: Install .NET 8.0
-        uses: actions/setup-dotnet@v5
+      - name: Install .NET 6.0
+        uses: actions/setup-dotnet@v4
         with:
-          dotnet-version: '8.0.x'
+          dotnet-version: '6.0.x'
 
       - name: Prepare Environment
         run: echo "GIT_TAG=${GITHUB_REF#refs/tags/}" >> ${GITHUB_ENV}
@@ -101,12 +101,12 @@ jobs:
     runs-on: ubuntu-22.04
     steps:
       - name: Clone Repository
-        uses: actions/checkout@v6
+        uses: actions/checkout@v4
 
-      - name: Install .NET 8.0
-        uses: actions/setup-dotnet@v5
+      - name: Install .NET 6.0
+        uses: actions/setup-dotnet@v4
         with:
-          dotnet-version: '8.0.x'
+          dotnet-version: '6.0.x'
 
       - name: Prepare Environment
         run: |
@@ -119,37 +119,9 @@ jobs:
           mkdir -p build/windows
           ./packaging/windows/buildpackage.sh "${GIT_TAG}" "${PWD}/build/windows"
 
-      - name: Upload Installer
-        id: unsigned-artifact
-        if: github.repository == 'openra/openra'
-        uses: actions/upload-artifact@v6
-        with:
-          path: build/windows/*.exe
-
-      - name: Microsoft Authenticode
-        id: signpath
-        if: github.repository == 'openra/openra'
-        uses: signpath/github-action-submit-signing-request@v2
-        with:
-          api-token: '${{ secrets.SIGNPATH_API_TOKEN }}'
-          organization-id: '${{ secrets.SIGNPATH_ORGANISATION_ID }}'
-          project-slug: 'OpenRA'
-          signing-policy-slug: 'release-signing'
-          github-artifact-id: '${{ steps.unsigned-artifact.outputs.artifact-id }}'
-          wait-for-completion: true
-          output-artifact-directory: 'build/windows/signed/'
-          parameters: |
-            version: ${{ toJSON(github.ref_name) }}
-
       - name: Upload Packages
         env:
           GH_TOKEN: ${{ secrets.GITHUB_TOKEN }}
         shell: bash
         run: |
-          gh release upload "${{ github.ref_name }}" build/windows/*.zip
-
-          if [ "${GITHUB_REPOSITORY}" = "openra/openra" ]; then
-            gh release upload "${{ github.ref_name }}" build/windows/signed/*.exe
-          else
-            gh release upload "${{ github.ref_name }}" build/windows/*.exe
-          fi
+          gh release upload ${{ github.ref_name }} build/windows/*

.gitignore

@@ -25,6 +25,10 @@ IP2LOCATION-LITE-DB1.IPV6.BIN.ZIP
 \#*
 .*.sw?
 
+# Monodevelop
+*.pidb
+*.userprefs
+
 # Mac OS X
 .DS_Store
 

AUTHORS

@@ -36,7 +36,6 @@ Also thanks to:
     * Andreas Beck (baxtor)
     * Ang Soon Li (asl97)
     * Arik Lirette (Angusm3)
-    * Ashley Newson
     * Barnaby Smith (mvi)
     * Bellator
     * Bernd Stellwag (burned42)
@@ -55,7 +54,6 @@ Also thanks to:
     * Constantin Helmig (CH4Code)
     * D2k Sardaukar
     * D'Arcy Rush (r34ch)
-    * Dan Stoian (stoiandan)
     * Daniel Derejvanik (Harisson)
     * Danny Keary (Dan9550)
     * David Jiménez (Rydra)
@@ -143,7 +141,6 @@ Also thanks to:
     * Riderr3
     * riiga
     * Rikhardur Bjarni Einarsson (WolfGaming)
-    * Robert Nordan (robpvn)
     * Sascha Biedermann (bidifx)
     * Sean Hunt (coppro)
     * Shawn Collins (UberWaffe)

CONTRIBUTING.md

@@ -24,6 +24,6 @@ Don't forget to add yourself to [AUTHORS](https://github.com/OpenRA/OpenRA/blob/
 
 Please propose a [CHANGELOG](https://github.com/OpenRA/OpenRA/wiki/CHANGELOG) entry in the pull-request comments.
 
-While your pull-request is in review it will be helpful if you join [Discord](https://discord.openra.net) or [IRC](ircs://irc.libera.chat:6697/openra) to discuss the changes.
+While your pull-request is in review it will be helpful if you join [IRC](irc://chat.freenode.net/openra) to discuss the changes.
 
 See also the in-depth guide on [contributing](https://github.com/OpenRA/OpenRA/wiki/Contributing) to the OpenRA project.

Directory.Build.props

@@ -5,7 +5,7 @@
     <CopyLocalLockFileAssemblies>true</CopyLocalLockFileAssemblies>
     <AllowUnsafeBlocks>true</AllowUnsafeBlocks>
     <Optimize>true</Optimize>
-    <LangVersion>12</LangVersion>
+    <LangVersion>9</LangVersion>
     <DebugSymbols>true</DebugSymbols>
     <EngineRootPath Condition="'$(EngineRootPath)' == ''">..</EngineRootPath>
     <OutputPath>$(EngineRootPath)/bin</OutputPath>
@@ -18,7 +18,8 @@
   </PropertyGroup>
 
   <PropertyGroup>
-    <TargetFramework>net8.0</TargetFramework>
+    <TargetFramework Condition="'$(MSBuildRuntimeType)'!='Mono'">net6.0</TargetFramework>
+    <TargetFramework Condition="'$(MSBuildRuntimeType)'=='Mono'">netstandard2.1</TargetFramework>
   </PropertyGroup>
 
   <PropertyGroup>
@@ -52,8 +53,9 @@
 
   <!-- StyleCop/Roslynator -->
   <ItemGroup>
-    <PackageReference Include="StyleCop.Analyzers" Version="1.2.0-beta.556" PrivateAssets="All" />
-    <PackageReference Include="Roslynator.Analyzers" Version="4.13.0" PrivateAssets="All" />
-    <PackageReference Include="Roslynator.Formatting.Analyzers" Version="4.13.0" PrivateAssets="All" />
+    <PackageReference Include="StyleCop.Analyzers" Version="1.2.0-beta.435" PrivateAssets="All" />
+    <!-- Roslynator analyzers fail to run under Mono (AD0001) -->
+    <PackageReference Include="Roslynator.Analyzers" Version="4.2.0" PrivateAssets="All" Condition="'$(MSBuildRuntimeType)'!='Mono'" />
+    <PackageReference Include="Roslynator.Formatting.Analyzers" Version="4.2.0" PrivateAssets="All" Condition="'$(MSBuildRuntimeType)'!='Mono'" />
   </ItemGroup>
 </Project>

Dockerfile

@@ -1,4 +1,4 @@
-FROM mcr.microsoft.com/dotnet/sdk:8.0
+FROM mcr.microsoft.com/dotnet/sdk:6.0
 
 RUN \
   apt-get update; \

INSTALL.md

@@ -8,7 +8,7 @@ Windows
 
 Compiling OpenRA requires the following dependencies:
 * [Windows PowerShell >= 4.0](https://microsoft.com/powershell) (included by default in recent Windows 10 versions)
-* [.NET 8 SDK](https://dotnet.microsoft.com/download/dotnet/8.0) (or via Visual Studio)
+* [.NET 6 SDK](https://dotnet.microsoft.com/download/dotnet/6.0) (or via Visual Studio)
 
 To compile OpenRA, open the `OpenRA.sln` solution in the main folder, build it from the command-line with `dotnet` or use the Makefile analogue command `make all` scripted in PowerShell syntax.
 
@@ -17,9 +17,11 @@ Run the game with `launch-game.cmd`. It can be handed arguments that specify the
 Linux
 =====
 
-.NET 8 is required to compile OpenRA. The [.NET 8 download page](https://dotnet.microsoft.com/download/dotnet/8.0) provides repositories for various package managers and binary releases for several architectures.
+.NET 6 or Mono (version 6.12 or later) is required to compile OpenRA. We recommend using .NET 6 when possible, as Mono is poorly packaged by most Linux distributions (e.g. missing the required `msbuild` toolchain), and has been deprecated as a standalone project.
 
-To compile OpenRA, run `make` from the command line. After this one can run the game with `./launch-game.sh`. It is also possible to specify the mod you wish to run from the command line, e.g. with `./launch-game.sh Game.Mod=ts` if you wish to try the experimental Tiberian Sun mod.
+The [.NET 6 download page](https://dotnet.microsoft.com/download/dotnet/6.0) provides repositories for various package managers and binary releases for several architectures. If you prefer to use Mono, we suggest adding the [upstream repository](https://www.mono-project.com/download/stable/#download-lin) for your distro to obtain the latest version and the `msbuild` toolchain.
+
+To compile OpenRA, run `make` from the command line (or `make RUNTIME=mono` if using Mono). After this one can run the game with `./launch-game.sh`. It is also possible to specify the mod you wish to run from the command line, e.g. with `./launch-game.sh Game.Mod=ts` if you wish to try the experimental Tiberian Sun mod.
 
 The default behaviour on the x86_64 architecture is to download several pre-compiled native libraries using the Nuget packaging manager. If you prefer to use system libraries, compile instead using `make TARGETPLATFORM=unix-generic`.
 
@@ -76,6 +78,6 @@ Type `sudo make install` for system-wide installation. Run `sudo make install-li
 macOS
 =====
 
-[.NET 8](https://dotnet.microsoft.com/download/dotnet/8.0) is required to compile OpenRA.
+[.NET 6](https://dotnet.microsoft.com/download/dotnet/6.0) or [Mono](https://www.mono-project.com/download/stable/#download-mac) (version 6.12 or later) is required to compile OpenRA. We recommend using .NET 6 unless you are running a very old version of macOS (10.9 through 10.14).
 
-To compile OpenRA, run `make` from the command line. Run with `./launch-game.sh`.
+To compile OpenRA, run `make` from the command line (or `make RUNTIME=mono` if using Mono). Run with `./launch-game.sh`.

Makefile

@@ -3,17 +3,20 @@
 # to compile, run:
 #   make
 #
+# to compile using Mono (version 6.12 or greater) instead of .NET 6, run:
+#   make RUNTIME=mono
+#
 # to compile using system libraries for native dependencies, run:
-#   make TARGETPLATFORM=unix-generic
+#   make [RUNTIME=net6] TARGETPLATFORM=unix-generic
 #
 # to check the official mods for erroneous yaml files, run:
-#   make test
+#   make [RUNTIME=net6] test
 #
 # to check the engine and official mod dlls for code style violations, run:
-#   make check
+#   make [RUNTIME=net6] check
 #
 # to compile and install Red Alert, Tiberian Dawn, and Dune 2000, run:
-#   make [prefix=/foo] [bindir=/bar/bin] install
+#   make [RUNTIME=net6] [prefix=/foo] [bindir=/bar/bin] install
 #
 # to compile and install Red Alert, Tiberian Dawn, and Dune 2000
 # using system libraries for native dependencies, run:
@@ -45,12 +48,15 @@ gameinstalldir ?= $(libdir)/openra
 
 # Toolchain
 CWD = $(shell pwd)
+MSBUILD = msbuild -verbosity:m -nologo
 DOTNET = dotnet
+MONO = mono
 RM = rm
 RM_R = $(RM) -r
 RM_F = $(RM) -f
 RM_RF = $(RM) -rf
 
+RUNTIME ?= net6
 CONFIGURATION ?= Release
 DOTNET_RID = $(shell ${DOTNET} --info | grep RID: | cut -w -f3)
 ARCH_X64 = $(shell echo ${DOTNET_RID} | grep x64)
@@ -85,12 +91,18 @@ endif
 #
 all:
 	@echo "Compiling in ${CONFIGURATION} mode..."
+ifeq ($(RUNTIME), mono)
+	@command -v $(firstword $(MSBUILD)) >/dev/null || (echo "OpenRA requires the '$(MSBUILD)' tool provided by Mono >= 6.12."; exit 1)
+	@$(MSBUILD) -t:Build -restore -p:Configuration=${CONFIGURATION} -p:TargetPlatform=$(TARGETPLATFORM)
+else
 	@$(DOTNET) build -c ${CONFIGURATION} -nologo -p:TargetPlatform=$(TARGETPLATFORM)
+endif
 ifeq ($(TARGETPLATFORM), unix-generic)
 	@./configure-system-libraries.sh
 endif
 	@./fetch-geoip.sh
 
+# dotnet clean and msbuild -t:Clean leave files that cause problems when switching between mono/dotnet
 # Deleting the intermediate / output directories ensures the build directory is actually clean
 clean:
 	@-$(RM_RF) ./bin ./*/obj
@@ -99,8 +111,12 @@ clean:
 check:
 	@echo
 	@echo "Compiling in Debug mode..."
+ifeq ($(RUNTIME), mono)
+	@$(MSBUILD) -t:clean\;build -restore -p:Configuration=Debug -warnaserror -p:TargetPlatform=$(TARGETPLATFORM)
+else
 	@$(DOTNET) clean -c Debug --nologo --verbosity minimal
 	@$(DOTNET) build -c Debug -nologo -warnaserror -p:TargetPlatform=$(TARGETPLATFORM)
+endif
 ifeq ($(TARGETPLATFORM), unix-generic)
 	@./configure-system-libraries.sh
 endif
@@ -119,19 +135,15 @@ check-scripts:
 test: all
 	@echo
 	@echo "Testing Tiberian Sun mod MiniYAML..."
-	@./utility.sh ts-content --check-yaml
 	@./utility.sh ts --check-yaml
 	@echo
 	@echo "Testing Dune 2000 mod MiniYAML..."
-	@./utility.sh d2k-content --check-yaml
 	@./utility.sh d2k --check-yaml
 	@echo
 	@echo "Testing Tiberian Dawn mod MiniYAML..."
-	@./utility.sh cnc-content --check-yaml
 	@./utility.sh cnc --check-yaml
 	@echo
 	@echo "Testing Red Alert mod MiniYAML..."
-	@./utility.sh ra-content --check-yaml
 	@./utility.sh ra --check-yaml
 
 tests:
@@ -149,7 +161,7 @@ endif
 	@sh -c '. ./packaging/functions.sh; set_mod_version "$(VERSION)" mods/*/mod.yaml'
 
 install:
-	@sh -c '. ./packaging/functions.sh; install_assemblies $(CWD) $(DESTDIR)$(gameinstalldir) $(TARGETPLATFORM) True True True'
+	@sh -c '. ./packaging/functions.sh; install_assemblies $(CWD) $(DESTDIR)$(gameinstalldir) $(TARGETPLATFORM) $(RUNTIME) True True True'
 	@sh -c '. ./packaging/functions.sh; install_data $(CWD) $(DESTDIR)$(gameinstalldir) cnc d2k ra'
 
 install-linux-shortcuts:
@@ -166,21 +178,24 @@ help:
 	@echo 'to compile, run:'
 	@echo '  make'
 	@echo
+	@echo 'to compile using Mono (version 6.12 or greater) instead of .NET 6, run:'
+	@echo '  make RUNTIME=mono'
+	@echo
 	@echo 'to compile using system libraries for native dependencies, run:'
-	@echo '  make TARGETPLATFORM=unix-generic'
+	@echo '  make [RUNTIME=net6] TARGETPLATFORM=unix-generic'
 	@echo
 	@echo 'to check the official mods for erroneous yaml files, run:'
-	@echo '  make [TREAT_WARNINGS_AS_ERRORS=false] test'
+	@echo '  make [RUNTIME=net6] [TREAT_WARNINGS_AS_ERRORS=false] test'
 	@echo
 	@echo 'to check the engine and official mod dlls for code style violations, run:'
-	@echo '  make check'
+	@echo '  make [RUNTIME=net6] check'
 	@echo
 	@echo 'to compile and install Red Alert, Tiberian Dawn, and Dune 2000 run:'
-	@echo '  make [prefix=/foo] [TARGETPLATFORM=unix-generic] install'
+	@echo '  make [RUNTIME=net6] [prefix=/foo] [TARGETPLATFORM=unix-generic] install'
 	@echo
 	@echo 'to compile and install Red Alert, Tiberian Dawn, and Dune 2000'
 	@echo 'using system libraries for native dependencies, run:'
-	@echo '   make [prefix=/foo] [bindir=/bar/bin] TARGETPLATFORM=unix-generic install'
+	@echo '   make [RUNTIME=net6] [prefix=/foo] [bindir=/bar/bin] TARGETPLATFORM=unix-generic install'
 	@echo
 	@echo 'to install FreeDesktop startup scripts, desktop files, icons, and MIME metadata'
 	@echo '  make install-linux-shortcuts'

OpenRA.Game/Actor.cs

@@ -89,21 +89,21 @@ namespace OpenRA
 		sealed class ConditionState
 		{
 			/// <summary>Delegates that have registered to be notified when this condition changes.</summary>
-			public readonly List<VariableObserverNotifier> Notifiers = [];
+			public readonly List<VariableObserverNotifier> Notifiers = new();
 
 			/// <summary>Unique integers identifying granted instances of the condition.</summary>
-			public readonly HashSet<int> Tokens = [];
+			public readonly HashSet<int> Tokens = new();
 		}
 
-		readonly Dictionary<string, ConditionState> conditionStates = [];
+		readonly Dictionary<string, ConditionState> conditionStates = new();
 
 		/// <summary>Each granted condition receives a unique token that is used when revoking.</summary>
-		readonly Dictionary<int, string> conditionTokens = [];
+		readonly Dictionary<int, string> conditionTokens = new();
 
 		int nextConditionToken = 1;
 
 		/// <summary>Cache of condition -> enabled state for quick evaluation of token counter conditions.</summary>
-		readonly Dictionary<string, int> conditionCache = [];
+		readonly Dictionary<string, int> conditionCache = new();
 
 		/// <summary>Read-only version of conditionCache that is passed to IConditionConsumers.</summary>
 		readonly IReadOnlyDictionary<string, int> readOnlyConditionCache;
@@ -123,9 +123,6 @@ namespace OpenRA
 		readonly IEnumerable<WPos> enabledTargetableWorldPositions;
 		bool created;
 
-		IEnumerable<IRenderable> renderables;
-		WorldRenderer lastWorldRenderer;
-
 		internal Actor(World world, string name, TypeDictionary initDict)
 		{
 			var duplicateInit = initDict.WithInterface<ISingleInstanceInit>().GroupBy(i => i.GetType())
@@ -290,18 +287,11 @@ namespace OpenRA
 
 		public IEnumerable<IRenderable> Render(WorldRenderer wr)
 		{
-			if (lastWorldRenderer != wr)
-			{
-				// PERF: Cache the enumerable to reduce allocations.
-				lastWorldRenderer = wr;
-				renderables = Renderables(wr);
-			}
-
 			// PERF: Avoid LINQ.
-			var modifiedRenderables = renderables;
+			var renderables = Renderables(wr);
 			foreach (var modifier in renderModifiers)
-				modifiedRenderables = modifier.ModifyRender(this, wr, modifiedRenderables);
-			return modifiedRenderables;
+				renderables = modifier.ModifyRender(this, wr, renderables);
+			return renderables;
 		}
 
 		IEnumerable<IRenderable> Renderables(WorldRenderer wr)
@@ -514,7 +504,7 @@ namespace OpenRA
 				if (!visibilityModifier.IsVisible(this, player))
 					return false;
 
-			return defaultVisibility?.IsVisible(this, player) ?? true;
+			return defaultVisibility.IsVisible(this, player);
 		}
 
 		public BitSet<TargetableType> GetAllTargetTypes()
@@ -551,7 +541,7 @@ namespace OpenRA
 			if (EnabledTargetablePositions.Any())
 				return enabledTargetableWorldPositions;
 
-			return [CenterPosition];
+			return new[] { CenterPosition };
 		}
 
 		#region Conditions

OpenRA.Game/CPos.cs

@@ -78,9 +78,17 @@ namespace OpenRA
 				return new MPos(X, Y);
 
 			// Convert from RectangularIsometric cell (x, y) position to rectangular map position (u, v)
-			// The staggered rows make this fiddly.
+			//  - The staggered rows make this fiddly (hint: draw a diagram!)
+			// (a) Consider the relationships:
+			//  - +1x (even -> odd) adds (0, 1) to (u, v)
+			//  - +1x (odd -> even) adds (1, 1) to (u, v)
+			//  - +1y (even -> odd) adds (-1, 1) to (u, v)
+			//  - +1y (odd -> even) adds (0, 1) to (u, v)
+			// (b) Therefore:
+			//  - ax + by adds (a - b)/2 to u (only even increments count)
+			//  - ax + by adds a + b to v
+			var u = (X - Y) / 2;
 			var v = X + Y;
-			var u = (v - (v & 1)) / 2 - Y;
 			return new MPos(u, v);
 		}
 

OpenRA.Game/CVec.cs

@@ -62,7 +62,7 @@ namespace OpenRA
 		public override string ToString() { return X + "," + Y; }
 
 		public static readonly CVec[] Directions =
-		[
+		{
 			new(-1, -1),
 			new(-1,  0),
 			new(-1,  1),
@@ -71,7 +71,7 @@ namespace OpenRA
 			new(1, -1),
 			new(1,  0),
 			new(1,  1),
-		];
+		};
 
 		#region Scripting interface
 

OpenRA.Game/CryptoUtil.cs

@@ -20,7 +20,7 @@ namespace OpenRA
 	public static class CryptoUtil
 	{
 		// Fixed byte pattern for the OID header
-		static readonly byte[] OIDHeader = [0x30, 0xD, 0x6, 0x9, 0x2A, 0x86, 0x48, 0x86, 0xF7, 0xD, 0x1, 0x1, 0x1, 0x5, 0x0];
+		static readonly byte[] OIDHeader = { 0x30, 0xD, 0x6, 0x9, 0x2A, 0x86, 0x48, 0x86, 0xF7, 0xD, 0x1, 0x1, 0x1, 0x5, 0x0 };
 
 		static readonly char[] HexUpperAlphabet = "0123456789ABCDEF".ToArray();
 		static readonly char[] HexLowerAlphabet = "0123456789abcdef".ToArray();
@@ -210,7 +210,8 @@ namespace OpenRA
 				using (var rsa = new RSACryptoServiceProvider())
 				{
 					rsa.ImportParameters(parameters);
-					return Convert.ToBase64String(rsa.SignHash(SHA1.HashData(data), CryptoConfig.MapNameToOID("SHA1")));
+					using (var csp = SHA1.Create())
+						return Convert.ToBase64String(rsa.SignHash(csp.ComputeHash(data), CryptoConfig.MapNameToOID("SHA1")));
 				}
 			}
 			catch (Exception e)
@@ -235,7 +236,8 @@ namespace OpenRA
 				using (var rsa = new RSACryptoServiceProvider())
 				{
 					rsa.ImportParameters(parameters);
-					return rsa.VerifyHash(SHA1.HashData(data), CryptoConfig.MapNameToOID("SHA1"), Convert.FromBase64String(signature));
+					using (var csp = SHA1.Create())
+						return rsa.VerifyHash(csp.ComputeHash(data), CryptoConfig.MapNameToOID("SHA1"), Convert.FromBase64String(signature));
 				}
 			}
 			catch (Exception e)
@@ -250,12 +252,14 @@ namespace OpenRA
 
 		public static string SHA1Hash(Stream data)
 		{
-			return ToHex(SHA1.HashData(data), true);
+			using var csp = SHA1.Create();
+			return ToHex(csp.ComputeHash(data), true);
 		}
 
 		public static string SHA1Hash(byte[] data)
 		{
-			return ToHex(SHA1.HashData(data), true);
+			using var csp = SHA1.Create();
+			return ToHex(csp.ComputeHash(data), true);
 		}
 
 		public static string SHA1Hash(string data)

OpenRA.Game/ExternalMods.cs

@@ -12,7 +12,6 @@
 using System;
 using System.Collections;
 using System.Collections.Generic;
-using System.Collections.Immutable;
 using System.IO;
 using System.Linq;
 using OpenRA.FileFormats;
@@ -29,7 +28,7 @@ namespace OpenRA
 		public readonly string Id;
 		public readonly string Version;
 		public readonly string LaunchPath;
-		public readonly ImmutableArray<string> LaunchArgs;
+		public readonly string[] LaunchArgs;
 		public Sprite Icon { get; internal set; }
 		public Sprite Icon2x { get; internal set; }
 		public Sprite Icon3x { get; internal set; }
@@ -41,7 +40,7 @@ namespace OpenRA
 
 	public class ExternalMods : IReadOnlyDictionary<string, ExternalMod>
 	{
-		readonly Dictionary<string, ExternalMod> mods = [];
+		readonly Dictionary<string, ExternalMod> mods = new();
 		readonly SheetBuilder sheetBuilder;
 
 		Sheet CreateSheet()
@@ -123,13 +122,13 @@ namespace OpenRA
 				return;
 
 			var key = ExternalMod.MakeKey(mod);
-			var yaml = new MiniYamlNode("Registration", new MiniYaml("",
-			[
+			var yaml = new MiniYamlNode("Registration", new MiniYaml("", new[]
+			{
 				new MiniYamlNode("Id", mod.Id),
 				new MiniYamlNode("Version", mod.Metadata.Version),
 				new MiniYamlNode("LaunchPath", launchPath),
 				new MiniYamlNode("LaunchArgs", new[] { "Game.Mod=" + mod.Id }.Concat(launchArgs).JoinWith(", "))
-			]));
+			}));
 
 			var iconNodes = new List<MiniYamlNode>();
 

OpenRA.Game/Exts.cs

@@ -11,11 +11,9 @@
 
 using System;
 using System.Collections.Generic;
-using System.Collections.Immutable;
 using System.Globalization;
 using System.Linq;
 using System.Reflection;
-using System.Runtime.InteropServices;
 using System.Text;
 using OpenRA.Primitives;
 using OpenRA.Support;
@@ -79,7 +77,7 @@ namespace OpenRA
 			return Math.Sign((v1.X - v0.X) * (p.Y - v0.Y) - (p.X - v0.X) * (v1.Y - v0.Y));
 		}
 
-		public static bool PolygonContains(this ImmutableArray<int2> polygon, int2 p)
+		public static bool PolygonContains(this int2[] polygon, int2 p)
 		{
 			var windingNumber = 0;
 
@@ -121,11 +119,17 @@ namespace OpenRA
 
 		public static V GetOrAdd<K, V>(this Dictionary<K, V> d, K k, V v)
 		{
+#if NET5_0_OR_GREATER
 			// SAFETY: Dictionary cannot be modified whilst the ref is alive.
-			ref var value = ref CollectionsMarshal.GetValueRefOrAddDefault(d, k, out var exists);
+			ref var value = ref System.Runtime.InteropServices.CollectionsMarshal.GetValueRefOrAddDefault(d, k, out var exists);
 			if (!exists)
 				value = v;
 			return value;
+#else
+			if (!d.TryGetValue(k, out var ret))
+				d.Add(k, ret = v);
+			return ret;
+#endif
 		}
 
 		public static V GetOrAdd<K, V>(this Dictionary<K, V> d, K k, Func<K, V> createFn)
@@ -414,6 +418,11 @@ namespace OpenRA
 			return ts.Except(exclusions);
 		}
 
+		public static HashSet<T> ToHashSet<T>(this IEnumerable<T> source)
+		{
+			return new HashSet<T>(source);
+		}
+
 		public static Dictionary<TKey, TSource> ToDictionaryWithConflictLog<TSource, TKey>(
 			this IEnumerable<TSource> source, Func<TSource, TKey> keySelector,
 			string debugName, Func<TKey, string> logKey, Func<TSource, string> logValue)
@@ -456,14 +465,14 @@ namespace OpenRA
 				// Check for a key conflict:
 				if (!output.TryAdd(key, element))
 				{
-					dupKeys ??= [];
+					dupKeys ??= new Dictionary<TKey, List<string>>();
 					if (!dupKeys.TryGetValue(key, out var dupKeyMessages))
 					{
 						// Log the initial conflicting value already inserted:
-						dupKeyMessages =
-						[
+						dupKeyMessages = new List<string>
+						{
 							logValue(output[key])
-						];
+						};
 						dupKeys.Add(key, dupKeyMessages);
 					}
 
@@ -478,7 +487,7 @@ namespace OpenRA
 				var badKeysFormatted = new StringBuilder(
 					$"{debugName}, duplicate values found for the following keys: ");
 				foreach (var p in dupKeys)
-					badKeysFormatted.Append(CultureInfo.InvariantCulture, $"{logKey(p.Key)}: [{string.Join(",", p.Value)}]");
+					badKeysFormatted.Append($"{logKey(p.Key)}: [{string.Join(",", p.Value)}]");
 				throw new ArgumentException(badKeysFormatted.ToString());
 			}
 		}
@@ -501,16 +510,44 @@ namespace OpenRA
 			return result;
 		}
 
+		public static T[,] ResizeArray<T>(T[,] ts, T t, int width, int height)
+		{
+			var result = new T[width, height];
+			for (var i = 0; i < width; i++)
+			{
+				for (var j = 0; j < height; j++)
+				{
+					// Workaround for broken ternary operators in certain versions of mono
+					// (3.10 and certain versions of the 3.8 series): https://bugzilla.xamarin.com/show_bug.cgi?id=23319
+					if (i <= ts.GetUpperBound(0) && j <= ts.GetUpperBound(1))
+						result[i, j] = ts[i, j];
+					else
+						result[i, j] = t;
+				}
+			}
+
+			return result;
+		}
+
+		public static int ToBits(this IEnumerable<bool> bits)
+		{
+			var i = 0;
+			var result = 0;
+			foreach (var b in bits)
+				if (b)
+					result |= 1 << i++;
+				else
+					i++;
+			if (i > 33)
+				throw new InvalidOperationException("ToBits only accepts up to 32 values.");
+			return result;
+		}
+
 		public static byte ParseByteInvariant(string s)
 		{
 			return byte.Parse(s, NumberStyles.Integer, NumberFormatInfo.InvariantInfo);
 		}
 
-		public static ushort ParseUshortInvariant(string s)
-		{
-			return ushort.Parse(s, NumberStyles.Integer, NumberFormatInfo.InvariantInfo);
-		}
-
 		public static short ParseInt16Invariant(string s)
 		{
 			return short.Parse(s, NumberStyles.Integer, NumberFormatInfo.InvariantInfo);
@@ -521,22 +558,6 @@ namespace OpenRA
 			return int.Parse(s, NumberStyles.Integer, NumberFormatInfo.InvariantInfo);
 		}
 
-		public static float ParseFloatOrPercentInvariant(string s)
-		{
-			var f = float.Parse(s.Replace("%", ""), NumberStyles.Float, NumberFormatInfo.InvariantInfo);
-			return f * (s.Contains('%') ? 0.01f : 1f);
-		}
-
-		public static bool TryParseByteInvariant(string s, out byte i)
-		{
-			return byte.TryParse(s, NumberStyles.Integer, NumberFormatInfo.InvariantInfo, out i);
-		}
-
-		public static bool TryParseUshortInvariant(string s, out ushort i)
-		{
-			return ushort.TryParse(s, NumberStyles.Integer, NumberFormatInfo.InvariantInfo, out i);
-		}
-
 		public static bool TryParseInt32Invariant(string s, out int i)
 		{
 			return int.TryParse(s, NumberStyles.Integer, NumberFormatInfo.InvariantInfo, out i);
@@ -547,17 +568,6 @@ namespace OpenRA
 			return long.TryParse(s, NumberStyles.Integer, NumberFormatInfo.InvariantInfo, out i);
 		}
 
-		public static bool TryParseFloatOrPercentInvariant(string s, out float f)
-		{
-			if (float.TryParse(s?.Replace("%", ""), NumberStyles.Float, NumberFormatInfo.InvariantInfo, out f))
-			{
-				f *= s.Contains('%') ? 0.01f : 1f;
-				return true;
-			}
-
-			return false;
-		}
-
 		public static string ToStringInvariant(this byte i)
 		{
 			return i.ToString(NumberFormatInfo.InvariantInfo);
@@ -573,16 +583,6 @@ namespace OpenRA
 			return i.ToString(NumberFormatInfo.InvariantInfo);
 		}
 
-		public static string ToStringInvariant(this uint i)
-		{
-			return i.ToString(NumberFormatInfo.InvariantInfo);
-		}
-
-		public static string ToStringInvariant(this float f)
-		{
-			return f.ToString(NumberFormatInfo.InvariantInfo);
-		}
-
 		public static string ToStringInvariant(this int i, string format)
 		{
 			return i.ToString(format, NumberFormatInfo.InvariantInfo);
@@ -665,7 +665,7 @@ namespace OpenRA
 			if (index == -1)
 			{
 				// The remaining string is an empty string
-				str = [];
+				str = ReadOnlySpan<char>.Empty;
 				Current = span;
 				return true;
 			}
@@ -677,4 +677,27 @@ namespace OpenRA
 
 		public ReadOnlySpan<char> Current { get; private set; }
 	}
+
+	public static class Enum<T>
+	{
+		public static T Parse(string s) { return (T)Enum.Parse(typeof(T), s); }
+		public static T[] GetValues() { return (T[])Enum.GetValues(typeof(T)); }
+
+		public static bool TryParse(string s, bool ignoreCase, out T value)
+		{
+			// The string may be a comma delimited list of values
+			var names = ignoreCase ? Enum.GetNames(typeof(T)).Select(x => x.ToLowerInvariant()) : Enum.GetNames(typeof(T));
+			var values = ignoreCase ? s.Split(',').Select(x => x.Trim().ToLowerInvariant()) : s.Split(',').Select(x => x.Trim());
+
+			if (values.Any(x => !names.Contains(x)))
+			{
+				value = default;
+				return false;
+			}
+
+			value = (T)Enum.Parse(typeof(T), s, ignoreCase);
+
+			return true;
+		}
+	}
 }

OpenRA.Game/FieldLoader.cs

@@ -10,14 +10,13 @@
 #endregion
 
 using System;
-using System.Collections.Frozen;
 using System.Collections.Generic;
-using System.Collections.Immutable;
 using System.ComponentModel;
 using System.Globalization;
 using System.IO;
 using System.Linq;
 using System.Reflection;
+using System.Runtime.Serialization;
 using OpenRA.Primitives;
 using OpenRA.Support;
 
@@ -25,8 +24,9 @@ namespace OpenRA
 {
 	public static class FieldLoader
 	{
-		const char Comma = ',';
+		const char SplitComma = ',';
 
+		[Serializable]
 		public class MissingFieldsException : YamlException
 		{
 			public readonly string[] Missing;
@@ -46,6 +46,13 @@ namespace OpenRA
 				Header = missing.Length > 1 ? header : headerSingle ?? header;
 				Missing = missing;
 			}
+
+			public override void GetObjectData(SerializationInfo info, StreamingContext context)
+			{
+				base.GetObjectData(info, context);
+				info.AddValue("Missing", Missing);
+				info.AddValue("Header", Header);
+			}
 		}
 
 		public static Func<string, Type, string, object> InvalidValueAction = (s, t, f) =>
@@ -61,8 +68,8 @@ namespace OpenRA
 		static readonly ConcurrentCache<string, IntegerExpression> IntegerExpressionCache =
 			new(expression => new IntegerExpression(expression));
 
-		static readonly FrozenDictionary<Type, Func<string, Type, string, object>> TypeParsers =
-			new Dictionary<Type, Func<string, Type, string, object>>
+		static readonly Dictionary<Type, Func<string, Type, string, MemberInfo, object>> TypeParsers =
+			new()
 			{
 				{ typeof(int), ParseInt },
 				{ typeof(ushort), ParseUShort },
@@ -85,6 +92,7 @@ namespace OpenRA
 				{ typeof(CVec[]), ParseCVecArray },
 				{ typeof(BooleanExpression), ParseBooleanExpression },
 				{ typeof(IntegerExpression), ParseIntegerExpression },
+				{ typeof(Enum), ParseEnum },
 				{ typeof(bool), ParseBool },
 				{ typeof(int2[]), ParseInt2Array },
 				{ typeof(Size), ParseSize },
@@ -93,44 +101,23 @@ namespace OpenRA
 				{ typeof(float3), ParseFloat3 },
 				{ typeof(Rectangle), ParseRectangle },
 				{ typeof(DateTime), ParseDateTime }
-			}.ToFrozenDictionary();
+			};
 
-		static readonly FrozenDictionary<Type, Func<string, Type, string, MiniYaml, object>> GenericTypeParsers =
-			new Dictionary<Type, Func<string, Type, string, MiniYaml, object>>
+		static readonly Dictionary<Type, Func<string, Type, string, MiniYaml, MemberInfo, object>> GenericTypeParsers =
+			new()
 			{
 				{ typeof(HashSet<>), ParseHashSetOrList },
 				{ typeof(List<>), ParseHashSetOrList },
 				{ typeof(Dictionary<,>), ParseDictionary },
-				{ typeof(ImmutableArray<>), ParseImmutableArray },
-				{ typeof(FrozenSet<>), ParseFrozenSet },
-				{ typeof(FrozenDictionary<,>), ParseFrozenDictionary },
 				{ typeof(BitSet<>), ParseBitSet },
 				{ typeof(Nullable<>), ParseNullable },
-			}.ToFrozenDictionary();
+			};
 
 		static readonly object BoxedTrue = true;
 		static readonly object BoxedFalse = false;
 		static readonly object[] BoxedInts = Exts.MakeArray(33, i => (object)i);
 
-		static readonly MethodInfo ToImmutableArray =
-			typeof(ImmutableArray)
-			.GetMethods()
-			.Single(m =>
-				m.Name == nameof(ImmutableArray.ToImmutableArray) &&
-				m.GetParameters()?.First().ParameterType.GetGenericTypeDefinition() == typeof(IEnumerable<>));
-
-		static readonly MethodInfo ToFrozenSet =
-			typeof(FrozenSet)
-			.GetMethod(nameof(FrozenSet.ToFrozenSet));
-
-		static readonly MethodInfo ToFrozenDictionary =
-			typeof(FrozenDictionary)
-			.GetMethods()
-			.Single(m =>
-				m.Name == nameof(FrozenDictionary.ToFrozenDictionary) &&
-				m.GetParameters().Length == 2);
-
-		static object ParseInt(string fieldName, Type fieldType, string value)
+		static object ParseInt(string fieldName, Type fieldType, string value, MemberInfo field)
 		{
 			if (Exts.TryParseInt32Invariant(value, out var res))
 			{
@@ -142,48 +129,48 @@ namespace OpenRA
 			return InvalidValueAction(value, fieldType, fieldName);
 		}
 
-		static object ParseUShort(string fieldName, Type fieldType, string value)
+		static object ParseUShort(string fieldName, Type fieldType, string value, MemberInfo field)
 		{
-			if (Exts.TryParseUshortInvariant(value, out var res))
+			if (ushort.TryParse(value, NumberStyles.Integer, NumberFormatInfo.InvariantInfo, out var res))
 				return res;
 			return InvalidValueAction(value, fieldType, fieldName);
 		}
 
-		static object ParseLong(string fieldName, Type fieldType, string value)
+		static object ParseLong(string fieldName, Type fieldType, string value, MemberInfo field)
 		{
-			if (Exts.TryParseInt64Invariant(value, out var res))
+			if (long.TryParse(value, NumberStyles.Integer, NumberFormatInfo.InvariantInfo, out var res))
 				return res;
 			return InvalidValueAction(value, fieldType, fieldName);
 		}
 
-		static object ParseFloat(string fieldName, Type fieldType, string value)
+		static object ParseFloat(string fieldName, Type fieldType, string value, MemberInfo field)
 		{
-			if (Exts.TryParseFloatOrPercentInvariant(value, out var res))
-				return res;
+			if (value != null && float.TryParse(value.Replace("%", ""), NumberStyles.Float, NumberFormatInfo.InvariantInfo, out var res))
+				return res * (value.Contains('%') ? 0.01f : 1f);
 			return InvalidValueAction(value, fieldType, fieldName);
 		}
 
-		static object ParseDecimal(string fieldName, Type fieldType, string value)
+		static object ParseDecimal(string fieldName, Type fieldType, string value, MemberInfo field)
 		{
 			if (value != null && decimal.TryParse(value.Replace("%", ""), NumberStyles.Float, NumberFormatInfo.InvariantInfo, out var res))
 				return res * (value.Contains('%') ? 0.01m : 1m);
 			return InvalidValueAction(value, fieldType, fieldName);
 		}
 
-		static object ParseString(string fieldName, Type fieldType, string value)
+		static object ParseString(string fieldName, Type fieldType, string value, MemberInfo field)
 		{
 			return value;
 		}
 
-		static object ParseColor(string fieldName, Type fieldType, string value)
+		static object ParseColor(string fieldName, Type fieldType, string value, MemberInfo field)
 		{
-			if (Color.TryParse(value, out var color))
+			if (value != null && Color.TryParse(value, out var color))
 				return color;
 
 			return InvalidValueAction(value, fieldType, fieldName);
 		}
 
-		static object ParseHotkey(string fieldName, Type fieldType, string value)
+		static object ParseHotkey(string fieldName, Type fieldType, string value, MemberInfo field)
 		{
 			if (Hotkey.TryParse(value, out var res))
 				return res;
@@ -191,12 +178,12 @@ namespace OpenRA
 			return InvalidValueAction(value, fieldType, fieldName);
 		}
 
-		static object ParseHotkeyReference(string fieldName, Type fieldType, string value)
+		static object ParseHotkeyReference(string fieldName, Type fieldType, string value, MemberInfo field)
 		{
 			return Game.ModData.Hotkeys[value];
 		}
 
-		static object ParseWDist(string fieldName, Type fieldType, string value)
+		static object ParseWDist(string fieldName, Type fieldType, string value, MemberInfo field)
 		{
 			if (WDist.TryParse(value, out var res))
 				return res;
@@ -204,11 +191,11 @@ namespace OpenRA
 			return InvalidValueAction(value, fieldType, fieldName);
 		}
 
-		static object ParseWVec(string fieldName, Type fieldType, string value)
+		static object ParseWVec(string fieldName, Type fieldType, string value, MemberInfo field)
 		{
 			if (value != null)
 			{
-				var parts = value.Split(Comma, StringSplitOptions.RemoveEmptyEntries | StringSplitOptions.TrimEntries);
+				var parts = value.Split(SplitComma);
 				if (parts.Length == 3
 					&& WDist.TryParse(parts[0], out var rx)
 					&& WDist.TryParse(parts[1], out var ry)
@@ -219,11 +206,11 @@ namespace OpenRA
 			return InvalidValueAction(value, fieldType, fieldName);
 		}
 
-		static object ParseWVecArray(string fieldName, Type fieldType, string value)
+		static object ParseWVecArray(string fieldName, Type fieldType, string value, MemberInfo field)
 		{
 			if (value != null)
 			{
-				var parts = value.Split(Comma, StringSplitOptions.RemoveEmptyEntries | StringSplitOptions.TrimEntries);
+				var parts = value.Split(SplitComma);
 
 				if (parts.Length % 3 != 0)
 					return InvalidValueAction(value, fieldType, fieldName);
@@ -236,8 +223,6 @@ namespace OpenRA
 						&& WDist.TryParse(parts[3 * i + 1], out var ry)
 						&& WDist.TryParse(parts[3 * i + 2], out var rz))
 						vecs[i] = new WVec(rx, ry, rz);
-					else
-						return InvalidValueAction(value, fieldType, fieldName);
 				}
 
 				return vecs;
@@ -246,11 +231,11 @@ namespace OpenRA
 			return InvalidValueAction(value, fieldType, fieldName);
 		}
 
-		static object ParseWPos(string fieldName, Type fieldType, string value)
+		static object ParseWPos(string fieldName, Type fieldType, string value, MemberInfo field)
 		{
 			if (value != null)
 			{
-				var parts = value.Split(Comma, StringSplitOptions.RemoveEmptyEntries | StringSplitOptions.TrimEntries);
+				var parts = value.Split(SplitComma);
 				if (parts.Length == 3
 					&& WDist.TryParse(parts[0], out var rx)
 					&& WDist.TryParse(parts[1], out var ry)
@@ -261,18 +246,18 @@ namespace OpenRA
 			return InvalidValueAction(value, fieldType, fieldName);
 		}
 
-		static object ParseWAngle(string fieldName, Type fieldType, string value)
+		static object ParseWAngle(string fieldName, Type fieldType, string value, MemberInfo field)
 		{
 			if (Exts.TryParseInt32Invariant(value, out var res))
 				return new WAngle(res);
 			return InvalidValueAction(value, fieldType, fieldName);
 		}
 
-		static object ParseWRot(string fieldName, Type fieldType, string value)
+		static object ParseWRot(string fieldName, Type fieldType, string value, MemberInfo field)
 		{
 			if (value != null)
 			{
-				var parts = value.Split(Comma, StringSplitOptions.RemoveEmptyEntries | StringSplitOptions.TrimEntries);
+				var parts = value.Split(SplitComma);
 				if (parts.Length == 3
 					&& Exts.TryParseInt32Invariant(parts[0], out var rr)
 					&& Exts.TryParseInt32Invariant(parts[1], out var rp)
@@ -283,31 +268,27 @@ namespace OpenRA
 			return InvalidValueAction(value, fieldType, fieldName);
 		}
 
-		static object ParseCPos(string fieldName, Type fieldType, string value)
+		static object ParseCPos(string fieldName, Type fieldType, string value, MemberInfo field)
 		{
 			if (value != null)
 			{
-				var parts = value.Split(Comma, StringSplitOptions.RemoveEmptyEntries | StringSplitOptions.TrimEntries);
-				if (parts.Length == 3
-					&& Exts.TryParseInt32Invariant(parts[0], out var x)
-					&& Exts.TryParseInt32Invariant(parts[1], out var y)
-					&& Exts.TryParseByteInvariant(parts[2], out var layer))
-					return new CPos(x, y, layer);
-
-				if (parts.Length == 2
-					&& Exts.TryParseInt32Invariant(parts[0], out x)
-					&& Exts.TryParseInt32Invariant(parts[1], out y))
-					return new CPos(x, y);
+				var parts = value.Split(SplitComma, StringSplitOptions.RemoveEmptyEntries);
+				if (parts.Length == 3)
+					return new CPos(
+						Exts.ParseInt32Invariant(parts[0]),
+						Exts.ParseInt32Invariant(parts[1]),
+						Exts.ParseByteInvariant(parts[2]));
+				return new CPos(Exts.ParseInt32Invariant(parts[0]), Exts.ParseInt32Invariant(parts[1]));
 			}
 
 			return InvalidValueAction(value, fieldType, fieldName);
 		}
 
-		static object ParseCPosArray(string fieldName, Type fieldType, string value)
+		static object ParseCPosArray(string fieldName, Type fieldType, string value, MemberInfo field)
 		{
 			if (value != null)
 			{
-				var parts = value.Split(Comma, StringSplitOptions.RemoveEmptyEntries | StringSplitOptions.TrimEntries);
+				var parts = value.Split(SplitComma);
 
 				if (parts.Length % 2 != 0)
 					return InvalidValueAction(value, fieldType, fieldName);
@@ -315,11 +296,9 @@ namespace OpenRA
 				var vecs = new CPos[parts.Length / 2];
 				for (var i = 0; i < vecs.Length; i++)
 				{
-					if (Exts.TryParseInt32Invariant(parts[2 * i], out var rx)
-						&& Exts.TryParseInt32Invariant(parts[2 * i + 1], out var ry))
+					if (int.TryParse(parts[2 * i], out var rx)
+							&& int.TryParse(parts[2 * i + 1], out var ry))
 						vecs[i] = new CPos(rx, ry);
-					else
-						return InvalidValueAction(value, fieldType, fieldName);
 				}
 
 				return vecs;
@@ -328,25 +307,22 @@ namespace OpenRA
 			return InvalidValueAction(value, fieldType, fieldName);
 		}
 
-		static object ParseCVec(string fieldName, Type fieldType, string value)
+		static object ParseCVec(string fieldName, Type fieldType, string value, MemberInfo field)
 		{
 			if (value != null)
 			{
-				var parts = value.Split(Comma, StringSplitOptions.RemoveEmptyEntries | StringSplitOptions.TrimEntries);
-				if (parts.Length == 2
-					&& Exts.TryParseInt32Invariant(parts[0], out var x)
-					&& Exts.TryParseInt32Invariant(parts[1], out var y))
-					return new CVec(x, y);
+				var parts = value.Split(SplitComma, StringSplitOptions.RemoveEmptyEntries);
+				return new CVec(Exts.ParseInt32Invariant(parts[0]), Exts.ParseInt32Invariant(parts[1]));
 			}
 
 			return InvalidValueAction(value, fieldType, fieldName);
 		}
 
-		static object ParseCVecArray(string fieldName, Type fieldType, string value)
+		static object ParseCVecArray(string fieldName, Type fieldType, string value, MemberInfo field)
 		{
 			if (value != null)
 			{
-				var parts = value.Split(Comma, StringSplitOptions.RemoveEmptyEntries | StringSplitOptions.TrimEntries);
+				var parts = value.Split(SplitComma);
 
 				if (parts.Length % 2 != 0)
 					return InvalidValueAction(value, fieldType, fieldName);
@@ -354,11 +330,9 @@ namespace OpenRA
 				var vecs = new CVec[parts.Length / 2];
 				for (var i = 0; i < vecs.Length; i++)
 				{
-					if (Exts.TryParseInt32Invariant(parts[2 * i], out var rx)
-						&& Exts.TryParseInt32Invariant(parts[2 * i + 1], out var ry))
+					if (int.TryParse(parts[2 * i], out var rx)
+							&& int.TryParse(parts[2 * i + 1], out var ry))
 						vecs[i] = new CVec(rx, ry);
-					else
-						return InvalidValueAction(value, fieldType, fieldName);
 				}
 
 				return vecs;
@@ -367,7 +341,7 @@ namespace OpenRA
 			return InvalidValueAction(value, fieldType, fieldName);
 		}
 
-		static object ParseBooleanExpression(string fieldName, Type fieldType, string value)
+		static object ParseBooleanExpression(string fieldName, Type fieldType, string value, MemberInfo field)
 		{
 			if (value != null)
 			{
@@ -377,14 +351,14 @@ namespace OpenRA
 				}
 				catch (InvalidDataException e)
 				{
-					throw new YamlException($"FieldLoader: Cannot parse `{value}` into `{fieldName}.{fieldType}`: {e.Message}");
+					throw new YamlException(e.Message);
 				}
 			}
 
 			return InvalidValueAction(value, fieldType, fieldName);
 		}
 
-		static object ParseIntegerExpression(string fieldName, Type fieldType, string value)
+		static object ParseIntegerExpression(string fieldName, Type fieldType, string value, MemberInfo field)
 		{
 			if (value != null)
 			{
@@ -394,50 +368,44 @@ namespace OpenRA
 				}
 				catch (InvalidDataException e)
 				{
-					throw new YamlException($"FieldLoader: Cannot parse `{value}` into `{fieldName}.{fieldType}`: {e.Message}");
+					throw new YamlException(e.Message);
 				}
 			}
 
 			return InvalidValueAction(value, fieldType, fieldName);
 		}
 
-		static object ParseEnum(string fieldName, Type fieldType, string value)
+		static object ParseEnum(string fieldName, Type fieldType, string value, MemberInfo field)
 		{
-			// Will allow numeric values that fit the underlying type of the enum, even if they aren't defined enumeration members.
-			if (Enum.TryParse(fieldType, value, true, out var enumValue))
+			try
 			{
-				return enumValue;
+				return Enum.Parse(fieldType, value, true);
 			}
-
+			catch (ArgumentException)
+			{
 				return InvalidValueAction(value, fieldType, fieldName);
 			}
+		}
 
-		static object ParseBool(string fieldName, Type fieldType, string value)
+		static object ParseBool(string fieldName, Type fieldType, string value, MemberInfo field)
 		{
-			if (bool.TryParse(value, out var result))
+			if (bool.TryParse(value.ToLowerInvariant(), out var result))
 				return result ? BoxedTrue : BoxedFalse;
 
 			return InvalidValueAction(value, fieldType, fieldName);
 		}
 
-		static object ParseInt2Array(string fieldName, Type fieldType, string value)
+		static object ParseInt2Array(string fieldName, Type fieldType, string value, MemberInfo field)
 		{
 			if (value != null)
 			{
-				var parts = value.Split(Comma, StringSplitOptions.RemoveEmptyEntries | StringSplitOptions.TrimEntries);
+				var parts = value.Split(SplitComma, StringSplitOptions.RemoveEmptyEntries);
 				if (parts.Length % 2 != 0)
 					return InvalidValueAction(value, fieldType, fieldName);
 
 				var ints = new int2[parts.Length / 2];
-
 				for (var i = 0; i < ints.Length; i++)
-				{
-					if (Exts.TryParseInt32Invariant(parts[2 * i], out var x)
-						&& Exts.TryParseInt32Invariant(parts[2 * i + 1], out var y))
-						ints[i] = new int2(x, y);
-					else
-						return InvalidValueAction(value, fieldType, fieldName);
-				}
+					ints[i] = new int2(Exts.ParseInt32Invariant(parts[2 * i]), Exts.ParseInt32Invariant(parts[2 * i + 1]));
 
 				return ints;
 			}
@@ -445,130 +413,109 @@ namespace OpenRA
 			return InvalidValueAction(value, fieldType, fieldName);
 		}
 
-		static object ParseSize(string fieldName, Type fieldType, string value)
+		static object ParseSize(string fieldName, Type fieldType, string value, MemberInfo field)
 		{
 			if (value != null)
 			{
-				var parts = value.Split(Comma, StringSplitOptions.RemoveEmptyEntries | StringSplitOptions.TrimEntries);
-				if (parts.Length == 2
-					&& Exts.TryParseInt32Invariant(parts[0], out var width)
-					&& Exts.TryParseInt32Invariant(parts[1], out var height))
-					return new Size(width, height);
+				var parts = value.Split(SplitComma, StringSplitOptions.RemoveEmptyEntries);
+				return new Size(Exts.ParseInt32Invariant(parts[0]), Exts.ParseInt32Invariant(parts[1]));
 			}
 
 			return InvalidValueAction(value, fieldType, fieldName);
 		}
 
-		static object ParseInt2(string fieldName, Type fieldType, string value)
+		static object ParseInt2(string fieldName, Type fieldType, string value, MemberInfo field)
 		{
 			if (value != null)
 			{
-				var parts = value.Split(Comma, StringSplitOptions.RemoveEmptyEntries | StringSplitOptions.TrimEntries);
-				if (parts.Length == 2
-					&& Exts.TryParseInt32Invariant(parts[0], out var x)
-					&& Exts.TryParseInt32Invariant(parts[1], out var y))
-					return new int2(x, y);
+				var parts = value.Split(SplitComma, StringSplitOptions.RemoveEmptyEntries);
+				if (parts.Length != 2)
+					return InvalidValueAction(value, fieldType, fieldName);
+
+				return new int2(Exts.ParseInt32Invariant(parts[0]), Exts.ParseInt32Invariant(parts[1]));
 			}
 
 			return InvalidValueAction(value, fieldType, fieldName);
 		}
 
-		static object ParseFloat2(string fieldName, Type fieldType, string value)
+		static object ParseFloat2(string fieldName, Type fieldType, string value, MemberInfo field)
 		{
 			if (value != null)
 			{
-				var parts = value.Split(Comma, StringSplitOptions.RemoveEmptyEntries | StringSplitOptions.TrimEntries);
-				if (parts.Length == 2
-					&& Exts.TryParseFloatOrPercentInvariant(parts[0], out var x)
-					&& Exts.TryParseFloatOrPercentInvariant(parts[1], out var y))
-					return new float2(x, y);
+				var parts = value.Split(SplitComma, StringSplitOptions.RemoveEmptyEntries);
+				float xx = 0;
+				float yy = 0;
+				if (float.TryParse(parts[0].Replace("%", ""), NumberStyles.Float, NumberFormatInfo.InvariantInfo, out var res))
+					xx = res * (parts[0].Contains('%') ? 0.01f : 1f);
+				if (float.TryParse(parts[1].Replace("%", ""), NumberStyles.Float, NumberFormatInfo.InvariantInfo, out res))
+					yy = res * (parts[1].Contains('%') ? 0.01f : 1f);
+				return new float2(xx, yy);
 			}
 
 			return InvalidValueAction(value, fieldType, fieldName);
 		}
 
-		static object ParseFloat3(string fieldName, Type fieldType, string value)
+		static object ParseFloat3(string fieldName, Type fieldType, string value, MemberInfo field)
 		{
 			if (value != null)
 			{
-				var parts = value.Split(Comma, StringSplitOptions.RemoveEmptyEntries | StringSplitOptions.TrimEntries);
-				if (parts.Length == 3
-					&& Exts.TryParseFloatOrPercentInvariant(parts[0], out var x)
-					&& Exts.TryParseFloatOrPercentInvariant(parts[1], out var y)
-					&& Exts.TryParseFloatOrPercentInvariant(parts[2], out var z))
-					return new float3(x, y, z);
+				var parts = value.Split(SplitComma, StringSplitOptions.RemoveEmptyEntries);
+				float.TryParse(parts[0], NumberStyles.Float, NumberFormatInfo.InvariantInfo, out var x);
+				float.TryParse(parts[1], NumberStyles.Float, NumberFormatInfo.InvariantInfo, out var y);
 
 				// z component is optional for compatibility with older float2 definitions
-				if (parts.Length == 2
-					&& Exts.TryParseFloatOrPercentInvariant(parts[0], out x)
-					&& Exts.TryParseFloatOrPercentInvariant(parts[1], out y))
-					return new float3(x, y, 0);
+				float z = 0;
+				if (parts.Length > 2)
+					float.TryParse(parts[2], NumberStyles.Float, NumberFormatInfo.InvariantInfo, out z);
+
+				return new float3(x, y, z);
 			}
 
 			return InvalidValueAction(value, fieldType, fieldName);
 		}
 
-		static object ParseRectangle(string fieldName, Type fieldType, string value)
+		static object ParseRectangle(string fieldName, Type fieldType, string value, MemberInfo field)
 		{
 			if (value != null)
 			{
-				var parts = value.Split(Comma, StringSplitOptions.RemoveEmptyEntries | StringSplitOptions.TrimEntries);
-				if (parts.Length == 4
-					&& Exts.TryParseInt32Invariant(parts[0], out var x)
-					&& Exts.TryParseInt32Invariant(parts[1], out var y)
-					&& Exts.TryParseInt32Invariant(parts[2], out var width)
-					&& Exts.TryParseInt32Invariant(parts[3], out var height))
-					return new Rectangle(x, y, width, height);
+				var parts = value.Split(SplitComma, StringSplitOptions.RemoveEmptyEntries);
+				return new Rectangle(
+					Exts.ParseInt32Invariant(parts[0]),
+					Exts.ParseInt32Invariant(parts[1]),
+					Exts.ParseInt32Invariant(parts[2]),
+					Exts.ParseInt32Invariant(parts[3]));
 			}
 
 			return InvalidValueAction(value, fieldType, fieldName);
 		}
 
-		static object ParseDateTime(string fieldName, Type fieldType, string value)
+		static object ParseDateTime(string fieldName, Type fieldType, string value, MemberInfo field)
 		{
 			if (DateTime.TryParseExact(value, "yyyy-MM-dd HH-mm-ss", CultureInfo.InvariantCulture, DateTimeStyles.AssumeUniversal, out var dt))
 				return dt;
 			return InvalidValueAction(value, fieldType, fieldName);
 		}
 
-		static object ParseArray(string fieldName, Type fieldType, string value)
-		{
-			var elementType = fieldType.GetElementType();
-
-			if (value == null)
-				return typeof(Array)
-					.GetMethod(nameof(Array.Empty))
-					.MakeGenericMethod(elementType)
-					.Invoke(null, null);
-
-			var parts = value.Split(Comma, StringSplitOptions.RemoveEmptyEntries | StringSplitOptions.TrimEntries);
-
-			var ret = Array.CreateInstance(elementType, parts.Length);
-			for (var i = 0; i < parts.Length; i++)
-				ret.SetValue(GetValue(fieldName, elementType, parts[i]), i);
-			return ret;
-		}
-
-		static object ParseHashSetOrList(string fieldName, Type fieldType, string value, MiniYaml yaml)
+		static object ParseHashSetOrList(string fieldName, Type fieldType, string value, MiniYaml yaml, MemberInfo field)
 		{
 			if (value == null)
 				return Activator.CreateInstance(fieldType);
 
-			var parts = value.Split(Comma, StringSplitOptions.RemoveEmptyEntries | StringSplitOptions.TrimEntries);
+			var parts = value.Split(SplitComma, StringSplitOptions.RemoveEmptyEntries);
 			var set = Activator.CreateInstance(fieldType, parts.Length);
 			var arguments = fieldType.GetGenericArguments();
 			var addMethod = fieldType.GetMethod(nameof(List<object>.Add), arguments);
 			var addArgs = new object[1];
 			for (var i = 0; i < parts.Length; i++)
 			{
-				addArgs[0] = GetValue(fieldName, arguments[0], parts[i]);
+				addArgs[0] = GetValue(fieldName, arguments[0], parts[i].Trim(), field);
 				addMethod.Invoke(set, addArgs);
 			}
 
 			return set;
 		}
 
-		static object ParseDictionary(string fieldName, Type fieldType, string value, MiniYaml yaml)
+		static object ParseDictionary(string fieldName, Type fieldType, string value, MiniYaml yaml, MemberInfo field)
 		{
 			if (yaml == null)
 				return Activator.CreateInstance(fieldType);
@@ -579,97 +526,34 @@ namespace OpenRA
 			var addArgs = new object[2];
 			foreach (var node in yaml.Nodes)
 			{
-				addArgs[0] = GetValue(fieldName, arguments[0], node.Key);
-				addArgs[1] = GetValue(fieldName, arguments[1], node.Value);
+				addArgs[0] = GetValue(fieldName, arguments[0], node.Key, field);
+				addArgs[1] = GetValue(fieldName, arguments[1], node.Value, field);
 				addMethod.Invoke(dict, addArgs);
 			}
 
 			return dict;
 		}
 
-		static object ParseImmutableArray(string fieldName, Type fieldType, string value, MiniYaml yaml)
-		{
-			var typeArgs = fieldType.GenericTypeArguments;
-
-			if (value == null)
-				return typeof(ImmutableArray<>).MakeGenericType(typeArgs)
-					.GetField(nameof(ImmutableArray<object>.Empty))
-					.GetValue(null);
-
-			object array;
-			if (typeArgs[0] == typeof(WVec))
-				array = ParseWVecArray(fieldName, typeArgs[0].MakeArrayType(), value);
-			else if (typeArgs[0] == typeof(CPos))
-				array = ParseCPosArray(fieldName, typeArgs[0].MakeArrayType(), value);
-			else if (typeArgs[0] == typeof(CVec))
-				array = ParseCVecArray(fieldName, typeArgs[0].MakeArrayType(), value);
-			else if (typeArgs[0] == typeof(int2))
-				array = ParseInt2Array(fieldName, typeArgs[0].MakeArrayType(), value);
-			else
-				array = ParseArray(fieldName, typeArgs[0].MakeArrayType(), value);
-
-			var toImmutableArray = ToImmutableArray.MakeGenericMethod(typeArgs);
-
-			return toImmutableArray.Invoke(null, [array]);
-		}
-
-		static object ParseFrozenSet(string fieldName, Type fieldType, string value, MiniYaml yaml)
-		{
-			var typeArgs = fieldType.GenericTypeArguments;
-
-			if (value == null)
-				return typeof(FrozenSet<>).MakeGenericType(typeArgs)
-					.GetProperty(nameof(FrozenSet<object>.Empty))
-					.GetValue(null);
-
-			var set =
-				ParseHashSetOrList(fieldName, typeof(HashSet<>).MakeGenericType(typeArgs), value, yaml);
-
-			var toFrozenSet = ToFrozenSet.MakeGenericMethod(typeArgs);
-
-			return toFrozenSet.Invoke(null, [set, null]);
-		}
-
-		static object ParseFrozenDictionary(string fieldName, Type fieldType, string value, MiniYaml yaml)
-		{
-			var typeArgs = fieldType.GenericTypeArguments;
-
-			if (yaml == null)
-				return typeof(FrozenDictionary<,>).MakeGenericType(typeArgs)
-					.GetProperty(nameof(FrozenDictionary<object, object>.Empty))
-					.GetValue(null);
-
-			var dict =
-				ParseDictionary(fieldName, typeof(Dictionary<,>).MakeGenericType(typeArgs), value, yaml);
-
-			var toFrozenDict = ToFrozenDictionary.MakeGenericMethod(typeArgs);
-
-			return toFrozenDict.Invoke(null, [dict, null]);
-		}
-
-		static object ParseBitSet(string fieldName, Type fieldType, string value, MiniYaml yaml)
+		static object ParseBitSet(string fieldName, Type fieldType, string value, MiniYaml yaml, MemberInfo field)
 		{
 			if (value != null)
 			{
-				var parts = value.Split(Comma, StringSplitOptions.RemoveEmptyEntries | StringSplitOptions.TrimEntries);
-				var ctor = fieldType.GetConstructor([typeof(string[])]);
-				return ctor.Invoke([parts]);
-			}
-			else
-			{
-				var ctor = fieldType.GetConstructor([typeof(string[])]);
-				return ctor.Invoke([Array.Empty<string>()]);
-			}
+				var parts = value.Split(SplitComma, StringSplitOptions.RemoveEmptyEntries);
+				var ctor = fieldType.GetConstructor(new[] { typeof(string[]) });
+				return ctor.Invoke(new object[] { parts.Select(p => p.Trim()).ToArray() });
 			}
 
-		static object ParseNullable(string fieldName, Type fieldType, string value, MiniYaml yaml)
+			return InvalidValueAction(value, fieldType, fieldName);
+		}
+
+		static object ParseNullable(string fieldName, Type fieldType, string value, MiniYaml yaml, MemberInfo field)
 		{
 			if (string.IsNullOrEmpty(value))
 				return null;
 
 			var innerType = fieldType.GetGenericArguments()[0];
-			var innerValue = GetValue("Nullable<T>", innerType, value);
-			return fieldType.GetConstructor([innerType]).Invoke([innerValue]);
+			var innerValue = GetValue("Nullable<T>", innerType, value, field);
+			return fieldType.GetConstructor(new[] { innerType }).Invoke(new[] { innerValue });
 		}
 
 		public static void Load(object self, MiniYaml my)
@@ -690,7 +574,7 @@ namespace OpenRA
 						val = fli.Loader(my);
 					else
 					{
-						missing ??= [];
+						missing ??= new List<string>();
 						missing.Add(fli.YamlName);
 						continue;
 					}
@@ -701,7 +585,7 @@ namespace OpenRA
 					{
 						if (fli.Attribute.Required)
 						{
-							missing ??= [];
+							missing ??= new List<string>();
 							missing.Add(fli.YamlName);
 						}
 
@@ -723,7 +607,7 @@ namespace OpenRA
 			if (!md.TryGetValue(yamlName, out var yaml))
 				return false;
 
-			ret = GetValue(field.Name, field.FieldType, yaml);
+			ret = GetValue(field.Name, field.FieldType, yaml, field);
 			return true;
 		}
 
@@ -734,7 +618,7 @@ namespace OpenRA
 			return t;
 		}
 
-		public static void LoadFieldOrProperty(object target, string key, string value)
+		public static void LoadField(object target, string key, string value)
 		{
 			const BindingFlags Flags = BindingFlags.Public | BindingFlags.NonPublic | BindingFlags.Instance;
 
@@ -743,14 +627,18 @@ namespace OpenRA
 			var field = target.GetType().GetField(key, Flags);
 			if (field != null)
 			{
-				field.SetValue(target, GetValue(field.Name, field.FieldType, value));
+				var sa = field.GetCustomAttributes<SerializeAttribute>(false).DefaultIfEmpty(SerializeAttribute.Default).First();
+				if (!sa.FromYamlKey)
+					field.SetValue(target, GetValue(field.Name, field.FieldType, value, field));
 				return;
 			}
 
 			var prop = target.GetType().GetProperty(key, Flags);
 			if (prop != null)
 			{
-				prop.SetValue(target, GetValue(prop.Name, prop.PropertyType, value), null);
+				var sa = prop.GetCustomAttributes<SerializeAttribute>(false).DefaultIfEmpty(SerializeAttribute.Default).First();
+				if (!sa.FromYamlKey)
+					prop.SetValue(target, GetValue(prop.Name, prop.PropertyType, value, prop), null);
 				return;
 			}
 
@@ -762,34 +650,48 @@ namespace OpenRA
 			return (T)GetValue(field, typeof(T), value, null);
 		}
 
-		static object GetValue(string fieldName, Type fieldType, string value)
+		public static object GetValue(string fieldName, Type fieldType, string value)
 		{
 			return GetValue(fieldName, fieldType, value, null);
 		}
 
-		static object GetValue(string fieldName, Type fieldType, MiniYaml yaml)
+		public static object GetValue(string fieldName, Type fieldType, string value, MemberInfo field)
 		{
-			return GetValue(fieldName, fieldType, yaml.Value, yaml);
+			return GetValue(fieldName, fieldType, value, null, field);
 		}
 
-		static object GetValue(string fieldName, Type fieldType, string value, MiniYaml yaml)
+		public static object GetValue(string fieldName, Type fieldType, MiniYaml yaml, MemberInfo field)
+		{
+			return GetValue(fieldName, fieldType, yaml.Value, yaml, field);
+		}
+
+		static object GetValue(string fieldName, Type fieldType, string value, MiniYaml yaml, MemberInfo field)
 		{
 			value = value?.Trim();
 			if (fieldType.IsGenericType)
 			{
 				if (GenericTypeParsers.TryGetValue(fieldType.GetGenericTypeDefinition(), out var parseFuncGeneric))
-					return parseFuncGeneric(fieldName, fieldType, value, yaml);
+					return parseFuncGeneric(fieldName, fieldType, value, yaml, field);
 			}
 			else
 			{
 				if (TypeParsers.TryGetValue(fieldType, out var parseFunc))
-					return parseFunc(fieldName, fieldType, value);
+					return parseFunc(fieldName, fieldType, value, field);
 
 				if (fieldType.IsArray && fieldType.GetArrayRank() == 1)
-					return ParseArray(fieldName, fieldType, value);
+				{
+					if (value == null)
+						return Array.CreateInstance(fieldType.GetElementType(), 0);
 
-				if (fieldType.IsEnum)
-					return ParseEnum(fieldName, fieldType, value);
+					var options = field != null && field.HasAttribute<AllowEmptyEntriesAttribute>() ?
+						StringSplitOptions.None : StringSplitOptions.RemoveEmptyEntries;
+					var parts = value.Split(SplitComma, options);
+
+					var ret = Array.CreateInstance(fieldType.GetElementType(), parts.Length);
+					for (var i = 0; i < parts.Length; i++)
+						ret.SetValue(GetValue(fieldName, fieldType.GetElementType(), parts[i].Trim(), field), i);
+					return ret;
+				}
 			}
 
 			var conv = TypeDescriptor.GetConverter(fieldType);
@@ -813,20 +715,21 @@ namespace OpenRA
 		{
 			public readonly FieldInfo Field;
 			public readonly SerializeAttribute Attribute;
+			public readonly string YamlName;
 			public readonly Func<MiniYaml, object> Loader;
-			public string YamlName => Field.Name;
 
-			public FieldLoadInfo(FieldInfo field, SerializeAttribute attr, Func<MiniYaml, object> loader = null)
+			internal FieldLoadInfo(FieldInfo field, SerializeAttribute attr, string yamlName, Func<MiniYaml, object> loader = null)
 			{
 				Field = field;
 				Attribute = attr;
+				YamlName = yamlName;
 				Loader = loader;
 			}
 		}
 
-		public static IEnumerable<FieldLoadInfo> GetTypeLoadInfo(Type type)
+		public static IEnumerable<FieldLoadInfo> GetTypeLoadInfo(Type type, bool includePrivateByDefault = false)
 		{
-			return TypeLoadInfo[type].Where(fli => fli.Field.IsPublic || (fli.Attribute.Serialize && !fli.Attribute.IsDefault));
+			return TypeLoadInfo[type].Where(fli => includePrivateByDefault || fli.Field.IsPublic || (fli.Attribute.Serialize && !fli.Attribute.IsDefault));
 		}
 
 		static FieldLoadInfo[] BuildTypeLoadInfo(Type type)
@@ -841,9 +744,13 @@ namespace OpenRA
 				if (!sa.Serialize)
 					continue;
 
-				var loader = sa.GetLoader(type);
+				var yamlName = string.IsNullOrEmpty(sa.YamlName) ? field.Name : sa.YamlName;
 
-				var fli = new FieldLoadInfo(field, sa, loader);
+				var loader = sa.GetLoader(type);
+				if (loader == null && sa.FromYamlKey)
+					loader = yaml => GetValue(yamlName, field.FieldType, yaml, field);
+
+				var fli = new FieldLoadInfo(field, sa, yamlName, loader);
 				ret.Add(fli);
 			}
 
@@ -854,21 +761,31 @@ namespace OpenRA
 		public sealed class IgnoreAttribute : SerializeAttribute
 		{
 			public IgnoreAttribute()
-				: base(serialize: false) { }
+				: base(false) { }
 		}
 
 		[AttributeUsage(AttributeTargets.Field)]
 		public sealed class RequireAttribute : SerializeAttribute
 		{
 			public RequireAttribute()
-				: base(serialize: true, required: true) { }
+				: base(true, true) { }
+		}
+
+		[AttributeUsage(AttributeTargets.Field)]
+		public sealed class AllowEmptyEntriesAttribute : SerializeAttribute
+		{
+			public AllowEmptyEntriesAttribute()
+				: base(allowEmptyEntries: true) { }
 		}
 
 		[AttributeUsage(AttributeTargets.Field)]
 		public sealed class LoadUsingAttribute : SerializeAttribute
 		{
 			public LoadUsingAttribute(string loader, bool required = false)
-				: base(serialize: true, required, loader) { }
+			{
+				Loader = loader;
+				Required = required;
+			}
 		}
 
 		[AttributeUsage(AttributeTargets.Field)]
@@ -879,14 +796,18 @@ namespace OpenRA
 			public bool IsDefault => this == Default;
 
 			public readonly bool Serialize;
-			public readonly bool Required;
-			public readonly string Loader;
+			public string YamlName;
+			public string Loader;
+			public bool FromYamlKey;
+			public bool DictionaryFromYamlKey;
+			public bool Required;
+			public bool AllowEmptyEntries;
 
-			protected SerializeAttribute(bool serialize = true, bool required = false, string loader = null)
+			public SerializeAttribute(bool serialize = true, bool required = false, bool allowEmptyEntries = false)
 			{
 				Serialize = serialize;
 				Required = required;
-				Loader = loader;
+				AllowEmptyEntries = allowEmptyEntries;
 			}
 
 			internal Func<MiniYaml, object> GetLoader(Type type)
@@ -906,4 +827,32 @@ namespace OpenRA
 			}
 		}
 	}
+
+	[AttributeUsage(AttributeTargets.Field)]
+	public sealed class FieldFromYamlKeyAttribute : FieldLoader.SerializeAttribute
+	{
+		public FieldFromYamlKeyAttribute()
+		{
+			FromYamlKey = true;
+		}
+	}
+
+	// Special-cases FieldFromYamlKeyAttribute for use with Dictionary<K,V>.
+	[AttributeUsage(AttributeTargets.Field)]
+	public sealed class DictionaryFromYamlKeyAttribute : FieldLoader.SerializeAttribute
+	{
+		public DictionaryFromYamlKeyAttribute()
+		{
+			FromYamlKey = true;
+			DictionaryFromYamlKey = true;
+		}
+	}
+
+	// Mirrors DescriptionAttribute from System.ComponentModel but we don't want to have to use that everywhere.
+	[AttributeUsage(AttributeTargets.All)]
+	public sealed class DescAttribute : Attribute
+	{
+		public readonly string[] Lines;
+		public DescAttribute(params string[] lines) { Lines = lines; }
+	}
 }

OpenRA.Game/FieldSaver.cs

@@ -10,9 +10,7 @@
 #endregion
 
 using System;
-using System.Collections.Frozen;
 using System.Collections.Generic;
-using System.Collections.Immutable;
 using System.ComponentModel;
 using System.Globalization;
 using System.Linq;
@@ -24,38 +22,39 @@ namespace OpenRA
 {
 	public static class FieldSaver
 	{
-		public static MiniYaml Save(object o)
+		public static MiniYaml Save(object o, bool includePrivateByDefault = false)
 		{
 			var nodes = new List<MiniYamlNode>();
+			string root = null;
 
-			foreach (var fieldInfo in FieldLoader.GetTypeLoadInfo(o.GetType()))
+			foreach (var info in FieldLoader.GetTypeLoadInfo(o.GetType(), includePrivateByDefault))
 			{
-				if (fieldInfo.Field.FieldType.IsGenericType && fieldInfo.Field.FieldType.IsAssignableTo(typeof(System.Collections.IDictionary)))
+				if (info.Attribute.DictionaryFromYamlKey)
 				{
-					var dict = (System.Collections.IDictionary)fieldInfo.Field.GetValue(o);
-					var dictNodes = new List<MiniYamlNode>();
+					var dict = (System.Collections.IDictionary)info.Field.GetValue(o);
 					foreach (var kvp in dict)
 					{
 						var key = ((System.Collections.DictionaryEntry)kvp).Key;
 						var value = ((System.Collections.DictionaryEntry)kvp).Value;
-						dictNodes.Add(new MiniYamlNode(FormatValue(key), FormatValue(value)));
-					}
 
-					nodes.Add(new MiniYamlNode(fieldInfo.YamlName, "", dictNodes));
+						nodes.Add(new MiniYamlNode(FormatValue(key), FormatValue(value)));
 					}
+				}
+				else if (info.Attribute.FromYamlKey)
+					root = FormatValue(o, info.Field);
 				else
-					nodes.Add(new MiniYamlNode(fieldInfo.YamlName, FormatValue(o, fieldInfo.Field)));
+					nodes.Add(new MiniYamlNode(info.YamlName, FormatValue(o, info.Field)));
 			}
 
-			return new MiniYaml(null, nodes);
+			return new MiniYaml(root, nodes);
 		}
 
-		public static MiniYaml SaveDifferences(object o, object from)
+		public static MiniYaml SaveDifferences(object o, object from, bool includePrivateByDefault = false)
 		{
 			if (o.GetType() != from.GetType())
-				throw new InvalidOperationException("FieldSaver: can't diff objects of different types");
+				throw new InvalidOperationException("FieldLoader: can't diff objects of different types");
 
-			var fields = FieldLoader.GetTypeLoadInfo(o.GetType())
+			var fields = FieldLoader.GetTypeLoadInfo(o.GetType(), includePrivateByDefault)
 				.Where(info => FormatValue(o, info.Field) != FormatValue(from, info.Field));
 
 			return new MiniYaml(
@@ -80,35 +79,11 @@ namespace OpenRA
 			if (t.IsArray && t.GetArrayRank() == 1)
 				return ((Array)v).Cast<object>().Select(FormatValue).JoinWith(", ");
 
-			if (t.IsGenericType &&
-				t.GetGenericTypeDefinition() == typeof(ImmutableArray<>))
-			{
-				try
-				{
-					return ((System.Collections.IEnumerable)v).Cast<object>().Select(FormatValue).JoinWith(", ");
-				}
-				catch (InvalidOperationException)
-				{
-					return "";
-				}
-			}
-
-			if (t.IsGenericType &&
-				(t.GetGenericTypeDefinition() == typeof(List<>) ||
-				t.GetGenericTypeDefinition() == typeof(HashSet<>) ||
-				t.GetGenericTypeDefinition()
-					.BaseTypes()
-					.Select(bt => bt.IsGenericType ? bt.GetGenericTypeDefinition() : null)
-					.Any(bt => bt == typeof(FrozenSet<>))))
+			if (t.IsGenericType && (t.GetGenericTypeDefinition() == typeof(HashSet<>) || t.GetGenericTypeDefinition() == typeof(List<>)))
 				return ((System.Collections.IEnumerable)v).Cast<object>().Select(FormatValue).JoinWith(", ");
 
 			// This is only for documentation generation
-			if (t.IsGenericType &&
-				(t.GetGenericTypeDefinition() == typeof(Dictionary<,>) ||
-				t.GetGenericTypeDefinition()
-					.BaseTypes()
-					.Select(bt => bt.IsGenericType ? bt.GetGenericTypeDefinition() : null)
-					.Any(bt => bt == typeof(FrozenDictionary<,>))))
+			if (t.IsGenericType && t.GetGenericTypeDefinition() == typeof(Dictionary<,>))
 			{
 				var result = new StringBuilder();
 				var dict = (System.Collections.IDictionary)v;
@@ -120,7 +95,7 @@ namespace OpenRA
 					var formattedKey = FormatValue(key);
 					var formattedValue = FormatValue(value);
 
-					result.Append(CultureInfo.InvariantCulture, $"{formattedKey}: {formattedValue}{Environment.NewLine}");
+					result.Append($"{formattedKey}: {formattedValue}{Environment.NewLine}");
 				}
 
 				return result.ToString();

OpenRA.Game/FileFormats/Png.cs

@@ -10,105 +10,29 @@
 #endregion
 
 using System;
-using System.Buffers;
-using System.Buffers.Binary;
 using System.Collections.Generic;
 using System.IO;
-using System.IO.Compression;
 using System.Linq;
 using System.Net;
 using System.Text;
+using ICSharpCode.SharpZipLib.Checksum;
+using ICSharpCode.SharpZipLib.Zip.Compression;
+using ICSharpCode.SharpZipLib.Zip.Compression.Streams;
 using OpenRA.Graphics;
 using OpenRA.Primitives;
 
 namespace OpenRA.FileFormats
 {
-	/// <summary>
-	/// Used to connect several IDAT chunks into a continuous stream.
-	/// </summary>
-	sealed class PngIdatStream : Stream
-	{
-		readonly Stream baseStream;
-		int remainingInChunk;
-		bool eof;
-
-		public PngIdatStream(Stream baseStream, int initialLen)
-		{
-			this.baseStream = baseStream;
-			remainingInChunk = initialLen;
-		}
-
-		public override int Read(byte[] buffer, int offset, int count) => Read(buffer.AsSpan(offset, count));
-
-		public override int Read(Span<byte> buffer)
-		{
-			if (eof || buffer.Length == 0)
-				return 0;
-
-			var totalRead = 0;
-			Span<byte> header = stackalloc byte[8];
-			while (buffer.Length > 0)
-			{
-				if (remainingInChunk == 0)
-				{
-					// Skip CRC and read next chunk header.
-					var r = baseStream.Seek(4, SeekOrigin.Current) + baseStream.Read(header);
-					if (r < 12)
-						throw new EndOfStreamException("Invalid PNG file - no end chunk found.");
-
-					// The PNG spec states that IDAT chunks must be chained together.
-					if (BinaryPrimitives.ReadUInt32BigEndian(header[4..]) == Png.ChunkIDAT)
-						remainingInChunk = BinaryPrimitives.ReadInt32BigEndian(header[..4]);
-					else
-					{
-						// This is not an IDAT chunk. Discontinue reading.
-						baseStream.Seek(-8, SeekOrigin.Current);
-						eof = true;
-						return totalRead;
-					}
-				}
-
-				var toRead = Math.Min(buffer.Length, remainingInChunk);
-				var read = baseStream.Read(buffer[..toRead]);
-				if (read == 0)
-					throw new EndOfStreamException("Unexpected end of stream in IDAT chunk.");
-
-				remainingInChunk -= read;
-				totalRead += read;
-				buffer = buffer[read..];
-			}
-
-			return totalRead;
-		}
-
-		public override bool CanRead => true;
-		public override bool CanSeek => false;
-		public override bool CanWrite => false;
-		public override long Length => throw new NotSupportedException();
-		public override long Position { get => throw new NotSupportedException(); set => throw new NotSupportedException(); }
-		public override void Flush() { }
-		public override long Seek(long offset, SeekOrigin origin) => throw new NotSupportedException();
-		public override void SetLength(long value) => throw new NotSupportedException();
-		public override void Write(byte[] buffer, int offset, int count) => throw new NotSupportedException();
-	}
-
 	public class Png
 	{
-		public const uint ChunkIHDR = 0x49484452;
-		public const uint ChunkPLTE = 0x504C5445;
-		public const uint ChunkIDAT = 0x49444154;
-		public const uint ChunkIEND = 0x49454E44;
-		public const uint ChunkTRNS = 0x74524E53;
-		public const uint ChunkTEXT = 0x74455874;
-
-		static readonly byte[] Signature = [0x89, 0x50, 0x4e, 0x47, 0x0d, 0x0a, 0x1a, 0x0a];
+		static readonly byte[] Signature = { 0x89, 0x50, 0x4e, 0x47, 0x0d, 0x0a, 0x1a, 0x0a };
 
 		public int Width { get; }
 		public int Height { get; }
 		public Color[] Palette { get; }
 		public byte[] Data { get; }
 		public SpriteFrameType Type { get; }
-		public Dictionary<string, string> EmbeddedData = [];
+		public Dictionary<string, string> EmbeddedData = new();
 
 		public int PixelStride => Type == SpriteFrameType.Indexed8 ? 1 : Type == SpriteFrameType.Rgb24 ? 3 : 4;
 
@@ -119,50 +43,43 @@ namespace OpenRA.FileFormats
 
 			s.Position += 8;
 			var headerParsed = false;
-			var dataParsed = false;
-			byte bitDepth = 8;
+			var data = new List<byte>();
 			Type = SpriteFrameType.Rgba32;
 
-			// Use a reusable 8-byte buffer for Length + Type.
-			Span<byte> chunkHeader = stackalloc byte[8];
-
+			byte bitDepth = 8;
 			while (true)
 			{
-				if (s.Read(chunkHeader) < 8)
-					throw new EndOfStreamException("Invalid PNG file - no end chunk found.");
+				var length = IPAddress.NetworkToHostOrder(s.ReadInt32());
+				var type = s.ReadASCII(4);
+				var content = s.ReadBytes(length);
+				s.ReadInt32(); // crc
 
-				var length = BinaryPrimitives.ReadInt32BigEndian(chunkHeader[..4]);
-				var type = BinaryPrimitives.ReadUInt32BigEndian(chunkHeader[4..]);
-
-				if (!headerParsed && type != ChunkIHDR)
+				if (!headerParsed && type != "IHDR")
 					throw new InvalidDataException("Invalid PNG file - header does not appear first.");
 
+				using (var ms = new MemoryStream(content))
+				{
 					switch (type)
 					{
-					case ChunkIHDR:
+						case "IHDR":
 						{
 							if (headerParsed)
 								throw new InvalidDataException("Invalid PNG file - duplicate header.");
+							Width = IPAddress.NetworkToHostOrder(ms.ReadInt32());
+							Height = IPAddress.NetworkToHostOrder(ms.ReadInt32());
 
-#pragma warning disable CA2014 // Do not use stackalloc in loops
-						Span<byte> buffer = stackalloc byte[13];
-#pragma warning restore CA2014 // Do not use stackalloc in loops
-						s.ReadBytes(buffer);
-
-						Width = BinaryPrimitives.ReadInt32BigEndian(buffer[..4]);
-						Height = BinaryPrimitives.ReadInt32BigEndian(buffer[4..8]);
-						bitDepth = buffer[8];
-						var colorType = (PngColorType)buffer[9];
-
+							bitDepth = ms.ReadUInt8();
+							var colorType = (PngColorType)ms.ReadUInt8();
 							if (IsPaletted(bitDepth, colorType))
 								Type = SpriteFrameType.Indexed8;
 							else if (colorType == PngColorType.Color)
 								Type = SpriteFrameType.Rgb24;
 
-						var compression = buffer[10];
+							Data = new byte[Width * Height * PixelStride];
 
-						// filter = buffer[11]
-						var interlace = buffer[12];
+							var compression = ms.ReadUInt8();
+							ms.ReadUInt8(); // filter
+							var interlace = ms.ReadUInt8();
 
 							if (compression != 0)
 								throw new InvalidDataException("Compression method not supported");
@@ -170,156 +87,73 @@ namespace OpenRA.FileFormats
 							if (interlace != 0)
 								throw new InvalidDataException("Interlacing not supported");
 
-						Data = new byte[Width * Height * PixelStride];
-
-						// Skip CRC.
-						s.Seek(4, SeekOrigin.Current);
 							headerParsed = true;
+
 							break;
 						}
 
-					case ChunkPLTE:
+						case "PLTE":
 						{
-						if (length % 3 != 0)
-							throw new InvalidDataException("Invalid PLTE chunk length.");
-
-						var count = length / 3;
-						Palette = new Color[count];
-
-						var buffer = ArrayPool<byte>.Shared.Rent(length);
-						try
+							Palette = new Color[length / 3];
+							for (var i = 0; i < Palette.Length; i++)
 							{
-							s.ReadBytes(buffer.AsSpan(0, length));
-							for (var i = 0; i < count; i++)
-							{
-								var offset = i * 3;
-								Palette[i] = Color.FromArgb(buffer[offset], buffer[offset + 1], buffer[offset + 2]);
-							}
-						}
-						finally
-						{
-							ArrayPool<byte>.Shared.Return(buffer);
+								var r = ms.ReadUInt8(); var g = ms.ReadUInt8(); var b = ms.ReadUInt8();
+								Palette[i] = Color.FromArgb(r, g, b);
 							}
 
-						// Skip CRC.
-						s.Seek(4, SeekOrigin.Current);
 							break;
 						}
 
-					case ChunkTRNS:
+						case "tRNS":
 						{
 							if (Palette == null)
 								throw new InvalidDataException("Non-Palette indexed PNG are not supported.");
 
-						var buffer = ArrayPool<byte>.Shared.Rent(length);
-						try
-						{
-							s.ReadBytes(buffer.AsSpan(0, length));
-							for (var i = 0; i < length && i < Palette.Length; i++)
-								Palette[i] = Color.FromArgb(buffer[i], Palette[i]);
-						}
-						finally
-						{
-							ArrayPool<byte>.Shared.Return(buffer);
-						}
+							for (var i = 0; i < length; i++)
+								Palette[i] = Color.FromArgb(ms.ReadUInt8(), Palette[i]);
 
-						// Skip CRC.
-						s.Seek(4, SeekOrigin.Current);
 							break;
 						}
 
-					case ChunkIDAT:
-						if (dataParsed)
-							throw new InvalidDataException("Invalid PNG file - discontinuous IDAT chunks.");
-
-						dataParsed = true;
-
-						ProcessIDAT(s, length, bitDepth);
-						break;
-
-					case ChunkTEXT:
+						case "IDAT":
 						{
-						var buffer = ArrayPool<byte>.Shared.Rent(length);
-						try
-						{
-							var span = buffer.AsSpan(0, length);
-							s.ReadBytes(span);
+							data.AddRange(content);
 
-							// Find Null Terminator for ASCIIZ (Keyword).
-							var nullIndex = span.IndexOf((byte)0);
-							if (nullIndex == -1)
-								return;
-
-							var key = Encoding.ASCII.GetString(span[..nullIndex]);
-							var value = Encoding.ASCII.GetString(span[(nullIndex + 1)..]);
-
-							EmbeddedData[key] = value;
-						}
-						finally
-						{
-							ArrayPool<byte>.Shared.Return(buffer);
-						}
-
-						// Skip CRC.
-						s.Seek(4, SeekOrigin.Current);
 							break;
 						}
 
-					case ChunkIEND:
+						case "tEXt":
 						{
-						if (Type == SpriteFrameType.Indexed8 && Palette == null)
-							throw new InvalidDataException("Non-Palette indexed PNG are not supported.");
+							var key = ms.ReadASCIIZ();
+							EmbeddedData.Add(key, ms.ReadASCII(length - key.Length - 1));
 
-						// Skip CRC.
-						s.Seek(4, SeekOrigin.Current);
-						return;
-					}
-
-					default:
-					{
-						// Skip unknown chunk + CRC.
-						s.Seek(length + 4, SeekOrigin.Current);
 							break;
 						}
-				}
-			}
-		}
 
-		void ProcessIDAT(Stream s, int firstChunkLength, byte bitDepth)
+						case "IEND":
+						{
+							using (var ns = new MemoryStream(data.ToArray()))
+							{
+								using (var ds = new InflaterInputStream(ns))
 								{
 									var pxStride = PixelStride;
 									var rowStride = Width * pxStride;
 									var pixelsPerByte = 8 / bitDepth;
 									var sourceRowStride = Exts.IntegerDivisionRoundingAwayFromZero(rowStride, pixelsPerByte);
 
-			// Custom stream that stitches IDAT chunks together without copying.
-			using var idatStream = new PngIdatStream(s, firstChunkLength);
-			using var ds = new ZLibStream(idatStream, CompressionMode.Decompress);
-
-			// Rent buffer from pool to avoid allocation churn.
-			var prevLineBuffer = ArrayPool<byte>.Shared.Rent(rowStride);
-			var prevLine = prevLineBuffer.AsSpan(0, rowStride);
-			prevLine.Clear();
-
-			try
-			{
+									Span<byte> prevLine = new byte[rowStride];
 									for (var y = 0; y < Height; y++)
 									{
-					var filterByte = ds.ReadByte();
-					if (filterByte == -1)
-						break;
-
-					var filter = (PngFilter)filterByte;
+										var filter = (PngFilter)ds.ReadUInt8();
+										ds.ReadBytes(Data, y * rowStride, sourceRowStride);
 										var line = Data.AsSpan(y * rowStride, rowStride);
 
-					ds.ReadBytes(line[..sourceRowStride]);
-
 										// If the source has a bit depth of 1, 2 or 4 it packs multiple pixels per byte.
 										// Unpack to bit depth of 8, yielding 1 pixel per byte.
 										// This makes life easier for consumers of palleted data.
 										if (bitDepth < 8)
 										{
-						var mask = (1 << bitDepth) - 1;
+											var mask = 0xFF >> (8 - bitDepth);
 											for (var i = sourceRowStride - 1; i >= 0; i--)
 											{
 												var packed = line[i];
@@ -327,7 +161,7 @@ namespace OpenRA.FileFormats
 												{
 													var dest = i * pixelsPerByte + j;
 													if (dest < line.Length) // Guard against last byte being only partially packed
-									line[dest] = (byte)((packed >> (8 - (j + 1) * bitDepth)) & mask);
+														line[dest] = (byte)(packed >> (8 - (j + 1) * bitDepth) & mask);
 												}
 											}
 										}
@@ -337,23 +171,23 @@ namespace OpenRA.FileFormats
 											case PngFilter.None:
 												break;
 											case PngFilter.Sub:
-							for (var i = pxStride; i < line.Length; i++)
+												for (var i = pxStride; i < rowStride; i++)
 													line[i] += line[i - pxStride];
 												break;
 											case PngFilter.Up:
-							for (var i = 0; i < line.Length; i++)
+												for (var i = 0; i < rowStride; i++)
 													line[i] += prevLine[i];
 												break;
 											case PngFilter.Average:
 												for (var i = 0; i < pxStride; i++)
 													line[i] += Average(0, prevLine[i]);
-							for (var i = pxStride; i < line.Length; i++)
+												for (var i = pxStride; i < rowStride; i++)
 													line[i] += Average(line[i - pxStride], prevLine[i]);
 												break;
 											case PngFilter.Paeth:
 												for (var i = 0; i < pxStride; i++)
 													line[i] += Paeth(0, prevLine[i], 0);
-							for (var i = pxStride; i < line.Length; i++)
+												for (var i = pxStride; i < rowStride; i++)
 													line[i] += Paeth(line[i - pxStride], prevLine[i], prevLine[i - pxStride]);
 												break;
 											default:
@@ -363,15 +197,6 @@ namespace OpenRA.FileFormats
 										prevLine = line;
 									}
 
-				// Drain remaining Zlib footer bytes if necessary.
-				Span<byte> drain = stackalloc byte[16];
-				while (ds.Read(drain) > 0) { }
-			}
-			finally
-			{
-				ArrayPool<byte>.Shared.Return(prevLineBuffer);
-			}
-
 									static byte Average(byte a, byte b) => (byte)((a + b) / 2);
 
 									static byte Paeth(byte a, byte b, byte c)
@@ -385,6 +210,17 @@ namespace OpenRA.FileFormats
 											(pb <= pc) ? b : c;
 									}
 								}
+							}
+
+							if (Type == SpriteFrameType.Indexed8 && Palette == null)
+								throw new InvalidDataException("Non-Palette indexed PNG are not supported.");
+
+							return;
+						}
+					}
+				}
+			}
+		}
 
 		public Png(byte[] data, SpriteFrameType type, int width, int height, Color[] palette = null,
 			Dictionary<string, string> embeddedData = null)
@@ -420,27 +256,14 @@ namespace OpenRA.FileFormats
 					// Convert to big endian
 					Data = new byte[data.Length];
 					var stride = PixelStride;
-					var elements = width * height * stride;
-					var src = data.AsSpan();
-					var dst = Data.AsSpan();
+					for (var i = 0; i < width * height; i++)
+					{
+						Data[stride * i] = data[stride * i + 2];
+						Data[stride * i + 1] = data[stride * i + 1];
+						Data[stride * i + 2] = data[stride * i + 0];
+
 						if (type == SpriteFrameType.Bgra32)
-					{
-						for (var i = 0; i < elements; i += 4)
-						{
-							dst[i + 0] = src[i + 2];
-							dst[i + 1] = src[i + 1];
-							dst[i + 2] = src[i + 0];
-							dst[i + 3] = src[i + 3];
-						}
-					}
-					else
-					{
-						for (var i = 0; i < elements; i += 3)
-						{
-							dst[i + 0] = src[i + 2];
-							dst[i + 1] = src[i + 1];
-							dst[i + 2] = src[i + 0];
-						}
+							Data[stride * i + 3] = data[stride * i + 3];
 					}
 
 					break;
@@ -457,8 +280,7 @@ namespace OpenRA.FileFormats
 		public static bool Verify(Stream s)
 		{
 			var pos = s.Position;
-			Span<byte> sigBuffer = stackalloc byte[8];
-			var isPng = s.Read(sigBuffer) == 8 && sigBuffer.SequenceEqual(Signature);
+			var isPng = Signature.Aggregate(true, (current, t) => current && s.ReadUInt8() == t);
 			s.Position = pos;
 			return isPng;
 		}
@@ -481,29 +303,24 @@ namespace OpenRA.FileFormats
 			throw new InvalidDataException("Unknown pixel format");
 		}
 
-		static void WritePngChunk(MemoryStream output, uint type, MemoryStream input)
+		static void WritePngChunk(Stream output, string type, Stream input)
 		{
-			Span<byte> header = stackalloc byte[8];
-			BinaryPrimitives.WriteInt32BigEndian(header[..4], (int)input.Length);
-			BinaryPrimitives.WriteUInt32BigEndian(header[4..], type);
+			input.Position = 0;
 
-			if (!input.TryGetBuffer(out var dataSegment))
-				dataSegment = new ArraySegment<byte>(input.ToArray());
+			var typeBytes = Encoding.ASCII.GetBytes(type);
+			output.Write(IPAddress.HostToNetworkOrder((int)input.Length));
+			output.Write(typeBytes);
 
-			ReadOnlySpan<byte> data = dataSegment.AsSpan(0, (int)input.Length);
-
-			output.Write(header);
+			var data = input.ReadAllBytes();
 			output.Write(data);
 
-			var crc = 0xFFFFFFFF;
-			crc = CRC32.Update(crc, header[4..]);
-			crc = CRC32.Update(crc, data);
-			var finalCrc = CRC32.Finish(crc);
-
-			output.Write(IPAddress.NetworkToHostOrder((int)finalCrc));
+			var crc32 = new Crc32();
+			crc32.Update(typeBytes);
+			crc32.Update(data);
+			output.Write(IPAddress.NetworkToHostOrder((int)crc32.Value));
 		}
 
-		public byte[] Save(CompressionLevel compression = CompressionLevel.SmallestSize)
+		public byte[] Save()
 		{
 			using (var output = new MemoryStream())
 			{
@@ -522,7 +339,7 @@ namespace OpenRA.FileFormats
 					header.WriteByte(0); // Filter
 					header.WriteByte(0); // Interlacing
 
-					WritePngChunk(output, ChunkIHDR, header);
+					WritePngChunk(output, "IHDR", header);
 				}
 
 				var alphaPalette = false;
@@ -538,7 +355,7 @@ namespace OpenRA.FileFormats
 							alphaPalette |= c.A > 0;
 						}
 
-						WritePngChunk(output, ChunkPLTE, palette);
+						WritePngChunk(output, "PLTE", palette);
 					}
 				}
 
@@ -549,13 +366,13 @@ namespace OpenRA.FileFormats
 						foreach (var c in Palette)
 							alpha.WriteByte(c.A);
 
-						WritePngChunk(output, ChunkTRNS, alpha);
+						WritePngChunk(output, "tRNS", alpha);
 					}
 				}
 
 				using (var data = new MemoryStream())
 				{
-					using (var compressed = new ZLibStream(data, compression, true))
+					using (var compressed = new DeflaterOutputStream(data, new Deflater(Deflater.BEST_COMPRESSION)))
 					{
 						var rowStride = Width * PixelStride;
 						for (var y = 0; y < Height; y++)
@@ -565,9 +382,12 @@ namespace OpenRA.FileFormats
 							compressed.WriteByte(FilterType);
 							compressed.Write(Data, y * rowStride, rowStride);
 						}
-					}
 
-					WritePngChunk(output, ChunkIDAT, data);
+						compressed.Flush();
+						compressed.Finish();
+
+						WritePngChunk(output, "IDAT", data);
+					}
 				}
 
 				foreach (var kv in EmbeddedData)
@@ -575,18 +395,18 @@ namespace OpenRA.FileFormats
 					using (var text = new MemoryStream())
 					{
 						text.Write(Encoding.ASCII.GetBytes(kv.Key + (char)0 + kv.Value));
-						WritePngChunk(output, ChunkTEXT, text);
+						WritePngChunk(output, "tEXt", text);
 					}
 				}
 
-				WritePngChunk(output, ChunkIEND, new MemoryStream());
+				WritePngChunk(output, "IEND", new MemoryStream());
 				return output.ToArray();
 			}
 		}
 
-		public void Save(string path, CompressionLevel compression = CompressionLevel.SmallestSize)
+		public void Save(string path)
 		{
-			File.WriteAllBytes(path, Save(compression));
+			File.WriteAllBytes(path, Save());
 		}
 	}
 }

OpenRA.Game/FileFormats/ReplayMetadata.cs

@@ -27,7 +27,8 @@ namespace OpenRA.FileFormats
 
 		public ReplayMetadata(GameInformation info)
 		{
-			ArgumentNullException.ThrowIfNull(info);
+			if (info == null)
+				throw new ArgumentNullException(nameof(info));
 
 			GameInfo = info;
 		}

OpenRA.Game/FileSystem/FileSystem.cs

@@ -29,16 +29,16 @@ namespace OpenRA.FileSystem
 	public class FileSystem : IReadOnlyFileSystem
 	{
 		public IEnumerable<IReadOnlyPackage> MountedPackages => mountedPackages.Keys;
-		readonly Dictionary<IReadOnlyPackage, int> mountedPackages = [];
-		readonly Dictionary<string, IReadOnlyPackage> explicitMounts = [];
+		readonly Dictionary<IReadOnlyPackage, int> mountedPackages = new();
+		readonly Dictionary<string, IReadOnlyPackage> explicitMounts = new();
 		readonly string modID;
 
 		// Mod packages that should not be disposed
-		readonly List<IReadOnlyPackage> modPackages = [];
+		readonly List<IReadOnlyPackage> modPackages = new();
 		readonly IReadOnlyDictionary<string, Manifest> installedMods;
 		readonly IPackageLoader[] packageLoaders;
 
-		Cache<string, List<IReadOnlyPackage>> fileIndex = new(_ => []);
+		Cache<string, List<IReadOnlyPackage>> fileIndex = new(_ => new List<IReadOnlyPackage>());
 
 		public FileSystem(string modID, IReadOnlyDictionary<string, Manifest> installedMods, IPackageLoader[] packageLoaders)
 		{
@@ -178,7 +178,7 @@ namespace OpenRA.FileSystem
 			explicitMounts.Clear();
 			modPackages.Clear();
 
-			fileIndex = new Cache<string, List<IReadOnlyPackage>>(_ => []);
+			fileIndex = new Cache<string, List<IReadOnlyPackage>>(_ => new List<IReadOnlyPackage>());
 		}
 
 		public void TrimExcess()

OpenRA.Game/FileSystem/Folder.cs

@@ -35,7 +35,7 @@ namespace OpenRA.FileSystem
 				return Directory.GetFiles(Name, "*", SearchOption.TopDirectoryOnly)
 					.Concat(Directory.GetDirectories(Name))
 					.Select(Path.GetFileName)
-					.Order();
+					.OrderBy(f => f);
 			}
 		}
 

OpenRA.Game/FileSystem/ZipFile.cs

@@ -98,11 +98,11 @@ namespace OpenRA.FileSystem
 		{
 			readonly MemoryStream pkgStream = new();
 
-			public ReadWriteZipFile(string filename = null, bool create = false)
+			public ReadWriteZipFile(string filename, bool create = false)
 			{
 				// SharpZipLib breaks when asked to update archives loaded from outside streams or files
 				// We can work around this by creating a clean in-memory-only file, cutting all outside references
-				if (!string.IsNullOrEmpty(filename) && !create)
+				if (!create)
 				{
 					using (var copy = new MemoryStream(File.ReadAllBytes(filename)))
 					{
@@ -120,26 +120,8 @@ namespace OpenRA.FileSystem
 					entry.ExtraData = null;
 			}
 
-			public ReadWriteZipFile(byte[] data)
-			{
-				using (var copy = new MemoryStream(data))
-				{
-					pkgStream.Capacity = (int)copy.Length;
-					copy.CopyTo(pkgStream);
-				}
-
-				pkgStream.Position = 0;
-				pkg = new ZipFile(pkgStream);
-				Name = null;
-
-				// Remove subfields that can break ZIP updating.
-				foreach (ZipEntry entry in pkg)
-					entry.ExtraData = null;
-			}
-
 			void Commit()
 			{
-				if (!string.IsNullOrEmpty(Name))
 				File.WriteAllBytes(Name, pkgStream.ToArray());
 			}
 

OpenRA.Game/FluentBundle.cs

@@ -11,7 +11,6 @@
 
 using System;
 using System.Collections.Generic;
-using System.Collections.Immutable;
 using System.Globalization;
 using System.IO;
 using Linguini.Bundle;
@@ -49,58 +48,23 @@ namespace OpenRA
 		}
 	}
 
-	[AttributeUsage(AttributeTargets.Class)]
-	public sealed class IncludeStaticFluentReferencesAttribute : Attribute
-	{
-		public readonly Type[] Types;
-
-		public IncludeStaticFluentReferencesAttribute(params Type[] types)
-		{
-			Types = types;
-		}
-	}
-
-	[AttributeUsage(AttributeTargets.Class)]
-	public sealed class IncludeChromeLogicArgsFluentReferencesAttribute : Attribute
-	{
-		public readonly string[] MethodNames;
-
-		public IncludeChromeLogicArgsFluentReferencesAttribute(params string[] methodNames)
-		{
-			MethodNames = methodNames;
-		}
-	}
-
-	[AttributeUsage(AttributeTargets.Field)]
-	public sealed class IncludeFluentReferencesAttribute : Attribute
-	{
-		public readonly LintDictionaryReference DictionaryReference;
-
-		public IncludeFluentReferencesAttribute() { }
-
-		public IncludeFluentReferencesAttribute(LintDictionaryReference dictionaryReference = LintDictionaryReference.None)
-		{
-			DictionaryReference = dictionaryReference;
-		}
-	}
-
 	public class FluentBundle
 	{
 		readonly Linguini.Bundle.FluentBundle bundle;
 
-		public FluentBundle(string culture, ImmutableArray<string> paths, IReadOnlyFileSystem fileSystem)
+		public FluentBundle(string culture, string[] paths, IReadOnlyFileSystem fileSystem)
 			: this(culture, paths, fileSystem, error => Log.Write("debug", error.Message)) { }
 
-		public FluentBundle(string culture, ImmutableArray<string> paths, IReadOnlyFileSystem fileSystem, string text)
+		public FluentBundle(string culture, string[] paths, IReadOnlyFileSystem fileSystem, string text)
 			: this(culture, paths, fileSystem, text, error => Log.Write("debug", error.Message)) { }
 
-		public FluentBundle(string culture, ImmutableArray<string> paths, IReadOnlyFileSystem fileSystem, Action<ParseError> onError)
+		public FluentBundle(string culture, string[] paths, IReadOnlyFileSystem fileSystem, Action<ParseError> onError)
 			: this(culture, paths, fileSystem, null, onError) { }
 
 		public FluentBundle(string culture, string text, Action<ParseError> onError)
-			: this(culture, default, null, text, onError) { }
+			: this(culture, null, null, text, onError) { }
 
-		public FluentBundle(string culture, ImmutableArray<string> paths, IReadOnlyFileSystem fileSystem, string text, Action<ParseError> onError)
+		public FluentBundle(string culture, string[] paths, IReadOnlyFileSystem fileSystem, string text, Action<ParseError> onError)
 		{
 			bundle = LinguiniBuilder.Builder()
 				.CultureInfo(new CultureInfo(culture))
@@ -147,7 +111,8 @@ namespace OpenRA
 
 		public bool TryGetMessage(string key, out string value, object[] args = null)
 		{
-			ArgumentNullException.ThrowIfNull(key);
+			if (key == null)
+				throw new ArgumentNullException(nameof(key));
 
 			try
 			{
@@ -164,7 +129,7 @@ namespace OpenRA
 						throw new ArgumentException("Expected a comma separated list of name, value arguments " +
 							"but the number of arguments is not a multiple of two", nameof(args));
 
-					fluentArgs = [];
+					fluentArgs = new Dictionary<string, IFluentType>();
 					for (var i = 0; i < args.Length; i += 2)
 					{
 						var argKey = args[i] as string;

OpenRA.Game/FluentProvider.cs

@@ -10,7 +10,6 @@
 #endregion
 
 using System;
-using System.Collections.Immutable;
 using System.Text;
 using OpenRA.FileSystem;
 
@@ -23,16 +22,16 @@ namespace OpenRA
 		static FluentBundle modFluentBundle;
 		static FluentBundle mapFluentBundle;
 
-		public static void Initialize(Manifest manifest, IReadOnlyFileSystem fileSystem)
+		public static void Initialize(ModData modData, IReadOnlyFileSystem fileSystem)
 		{
 			lock (SyncObject)
 			{
-				modFluentBundle = new FluentBundle(manifest.FluentCulture, manifest.FluentMessages, fileSystem);
+				modFluentBundle = new FluentBundle(modData.Manifest.FluentCulture, modData.Manifest.FluentMessages, fileSystem);
 				if (fileSystem is Map map && map.FluentMessageDefinitions != null)
 				{
-					var files = ImmutableArray<string>.Empty;
+					var files = Array.Empty<string>();
 					if (map.FluentMessageDefinitions.Value != null)
-						files = FieldLoader.GetValue<ImmutableArray<string>>("value", map.FluentMessageDefinitions.Value);
+						files = FieldLoader.GetValue<string[]>("value", map.FluentMessageDefinitions.Value);
 
 					string text = null;
 					if (map.FluentMessageDefinitions.Nodes.Length > 0)
@@ -45,7 +44,7 @@ namespace OpenRA
 						text = builder.ToString();
 					}
 
-					mapFluentBundle = new FluentBundle(manifest.FluentCulture, files, fileSystem, text);
+					mapFluentBundle = new FluentBundle(modData.Manifest.FluentCulture, files, fileSystem, text);
 				}
 			}
 		}

OpenRA.Game/Fonts.cs

@@ -9,7 +9,6 @@
  */
 #endregion
 
-using System.Collections.Frozen;
 using System.Collections.Generic;
 
 namespace OpenRA
@@ -24,15 +23,15 @@ namespace OpenRA
 	public class Fonts : IGlobalModData
 	{
 		[FieldLoader.LoadUsing(nameof(LoadFonts))]
-		public readonly FrozenDictionary<string, FontData> FontList;
+		public readonly Dictionary<string, FontData> FontList;
 
 		static object LoadFonts(MiniYaml y)
 		{
-			var ret = new Dictionary<string, FontData>(y.Nodes.Length);
+			var ret = new Dictionary<string, FontData>();
 			foreach (var node in y.Nodes)
 				ret.Add(node.Key, FieldLoader.Load<FontData>(node.Value));
 
-			return ret.ToFrozenDictionary();
+			return ret;
 		}
 	}
 }

OpenRA.Game/Game.cs

@@ -11,7 +11,6 @@
 
 using System;
 using System.Collections.Generic;
-using System.Collections.Immutable;
 using System.Diagnostics;
 using System.Globalization;
 using System.IO;
@@ -28,7 +27,6 @@ using OpenRA.Widgets;
 
 namespace OpenRA
 {
-	[IncludeStaticFluentReferences(typeof(Server.Server), typeof(Player), typeof(UnitOrders), typeof(OrderManager))]
 	public static class Game
 	{
 		[FluentReference("filename")]
@@ -168,7 +166,6 @@ namespace OpenRA
 		{
 			return ModData.WidgetLoader.LoadWidget(new WidgetArgs(args)
 			{
-				{ "modData", ModData },
 				{ "world", world },
 				{ "orderManager", OrderManager },
 				{ "worldRenderer", worldRenderer },
@@ -184,16 +181,7 @@ namespace OpenRA
 
 		public static event Action BeforeGameStart = () => { };
 		public static event Action AfterGameStart = () => { };
-		internal static void StartGame(string uid, WorldType type)
-		{
-			var preview = ModData.MapCache[uid];
-			if (preview.Status != MapStatus.Available)
-				throw new InvalidDataException($"Invalid map uid: {uid}");
-
-			StartGame(preview.ToMap(), type);
-		}
-
-		internal static void StartGame(Map map, WorldType type)
+		internal static void StartGame(string mapUID, WorldType type)
 		{
 			// Dispose of the old world before creating a new one.
 			worldRenderer?.Dispose();
@@ -202,23 +190,7 @@ namespace OpenRA
 			BeforeGameStart();
 
 			using (new PerfTimer("NewWorld"))
-			{
-				ModData.PrepareMap(map);
-
-				// The depth buffer needs to be initialized with enough range to cover:
-				//  - the height of the screen
-				//  - the z-offset of tiles from MaxTerrainHeight below the bottom of the screen (pushed into view)
-				//  - additional z-offset from actors on top of MaxTerrainHeight terrain
-				//  - a small margin so that tiles rendered partially above the top edge of the screen aren't pushed behind the clip plane
-				// We need an offset of mapGrid.MaximumTerrainHeight * mapGrid.TileSize.Height / 2 to cover the terrain height
-				// and choose to use mapGrid.MaximumTerrainHeight * mapGrid.TileSize.Height / 4 for each of the actor and top-edge cases
-				var margin = 0;
-				if (map.Grid.EnableDepthBuffer)
-					margin = map.Rules.TerrainInfo.TileSize.Height * map.Grid.MaximumTerrainHeight;
-
-				Renderer.SetDepthMargin(margin);
-				OrderManager.World = new World(map, ModData, OrderManager, type);
-			}
+				OrderManager.World = new World(mapUID, ModData, OrderManager, type);
 
 			OrderManager.World.GameOver += FinishBenchmark;
 
@@ -372,7 +344,7 @@ namespace OpenRA
 			var explicitModPaths = Array.Empty<string>();
 			if (modID != null && (File.Exists(modID) || Directory.Exists(modID)))
 			{
-				explicitModPaths = [modID];
+				explicitModPaths = new[] { modID };
 				modID = Path.GetFileNameWithoutExtension(modID);
 			}
 
@@ -387,48 +359,6 @@ namespace OpenRA
 			Log.AddChannel("nat", "nat.log");
 			Log.AddChannel("client", "client.log");
 
-			Nat.Initialize();
-
-			var modSearchArg = args.GetValue("Engine.ModSearchPaths", null);
-			var modSearchPaths = modSearchArg != null ?
-				FieldLoader.GetValue<ImmutableArray<string>>("Engine.ModsPath", modSearchArg) :
-				[Path.Combine(Platform.EngineDir, "mods")];
-
-			Mods = new InstalledMods(modSearchPaths, explicitModPaths);
-			Console.WriteLine("Internal mods:");
-			foreach (var mod in Mods)
-				Console.WriteLine($"\t{mod.Key} ({mod.Value.Metadata.Version})");
-
-			modLaunchWrapper = args.GetValue("Engine.LaunchWrapper", null);
-
-			ExternalMods = new ExternalMods();
-
-			if (modID == null)
-				throw new InvalidOperationException("Game.Mod argument missing.");
-
-			if (Mods.TryGetValue(modID, out var manifest))
-			{
-				var launchPath = args.GetValue("Engine.LaunchPath", null);
-				var launchArgs = new List<string>();
-
-				// Sanitize input from platform-specific launchers
-				// Process.Start requires paths to not be quoted, even if they contain spaces
-				if (launchPath != null && launchPath[0] == '"' && launchPath[^1] == '"')
-					launchPath = launchPath[1..^1];
-
-				// Metadata registration requires an explicit launch path
-				if (launchPath != null)
-					ExternalMods.Register(Mods[modID], launchPath, launchArgs, ModRegistration.User);
-
-				ExternalMods.ClearInvalidRegistrations(ModRegistration.User);
-			}
-			else
-				throw new InvalidOperationException($"Unknown or invalid mod '{modID}'.");
-
-			Console.WriteLine("External mods:");
-			foreach (var mod in ExternalMods)
-				Console.WriteLine($"\t{mod.Key} ({mod.Value.Version})");
-
 			var platforms = new[] { Settings.Game.Platform, "Default", null };
 			foreach (var p in platforms)
 			{
@@ -439,7 +369,7 @@ namespace OpenRA
 				try
 				{
 					var platform = CreatePlatform(p);
-					Renderer = new Renderer(platform, Settings.Graphics, manifest.RendererConstants.VertexBatchSize);
+					Renderer = new Renderer(platform, Settings.Graphics);
 					Sound = new Sound(platform, Settings.Sound);
 
 					break;
@@ -455,23 +385,67 @@ namespace OpenRA
 				}
 			}
 
-			InitializeMod(manifest, args);
+			Nat.Initialize();
+
+			var modSearchArg = args.GetValue("Engine.ModSearchPaths", null);
+			var modSearchPaths = modSearchArg != null ?
+				FieldLoader.GetValue<string[]>("Engine.ModsPath", modSearchArg) :
+				new[] { Path.Combine(Platform.EngineDir, "mods") };
+
+			Mods = new InstalledMods(modSearchPaths, explicitModPaths);
+			Console.WriteLine("Internal mods:");
+			foreach (var mod in Mods)
+				Console.WriteLine($"\t{mod.Key} ({mod.Value.Metadata.Version})");
+
+			modLaunchWrapper = args.GetValue("Engine.LaunchWrapper", null);
+
+			ExternalMods = new ExternalMods();
+
+			if (modID != null && Mods.TryGetValue(modID, out _))
+			{
+				var launchPath = args.GetValue("Engine.LaunchPath", null);
+				var launchArgs = new List<string>();
+
+				// Sanitize input from platform-specific launchers
+				// Process.Start requires paths to not be quoted, even if they contain spaces
+				if (launchPath != null && launchPath[0] == '"' && launchPath.Last() == '"')
+					launchPath = launchPath[1..^1];
+
+				// Metadata registration requires an explicit launch path
+				if (launchPath != null)
+					ExternalMods.Register(Mods[modID], launchPath, launchArgs, ModRegistration.User);
+
+				ExternalMods.ClearInvalidRegistrations(ModRegistration.User);
+			}
+
+			Console.WriteLine("External mods:");
+			foreach (var mod in ExternalMods)
+				Console.WriteLine($"\t{mod.Key} ({mod.Value.Version})");
+
+			InitializeMod(modID, args);
 		}
 
 		public static IPlatform CreatePlatform(string platformName)
 		{
 			var rendererPath = Path.Combine(Platform.BinDir, "OpenRA.Platforms." + platformName + ".dll");
 
+#if NET5_0_OR_GREATER
 			var loader = new AssemblyLoader(rendererPath);
 			var platformType = loader.LoadDefaultAssembly().GetTypes().SingleOrDefault(t => typeof(IPlatform).IsAssignableFrom(t));
 
+#else
+			// NOTE: This is currently the only use of System.Reflection in this file, so would give an unused using error if we import it above
+			var assembly = System.Reflection.Assembly.LoadFile(rendererPath);
+			var platformType = assembly.GetTypes().SingleOrDefault(t => typeof(IPlatform).IsAssignableFrom(t));
+#endif
+
 			if (platformType == null)
 				throw new InvalidOperationException("Platform dll must include exactly one IPlatform implementation.");
 
 			return (IPlatform)platformType.GetConstructor(Type.EmptyTypes).Invoke(null);
 		}
 
-		public static void InitializeMod(Manifest manifest, Arguments args)
+		public static void InitializeMod(string mod, Arguments args)
 		{
 			// Clear static state if we have switched mods
 			LobbyInfoChanged = () => { };
@@ -495,25 +469,34 @@ namespace OpenRA
 
 			ModData = null;
 
-			Console.WriteLine($"Loading mod: {manifest.Id}");
+			if (mod == null)
+				throw new InvalidOperationException("Game.Mod argument missing.");
+
+			if (!Mods.ContainsKey(mod))
+				throw new InvalidOperationException($"Unknown or invalid mod '{mod}'.");
+
+			Console.WriteLine($"Loading mod: {mod}");
 
 			Sound.StopVideo();
 
-			ModData = new ModData(manifest, Mods, true);
+			ModData = new ModData(Mods[mod], Mods, true);
 
-			LocalPlayerProfile = new LocalPlayerProfile(Path.Combine(Platform.SupportDir, Settings.Game.AuthProfile), ModData.GetOrCreate<PlayerDatabase>());
+			LocalPlayerProfile = new LocalPlayerProfile(Path.Combine(Platform.SupportDir, Settings.Game.AuthProfile), ModData.Manifest.Get<PlayerDatabase>());
 
-			if (!ModData.LoadScreen.BeforeLoad(ModData))
+			if (!ModData.LoadScreen.BeforeLoad())
 				return;
 
 			ModData.InitializeLoaders(ModData.DefaultFileSystem);
 			Renderer.InitializeFonts(ModData);
 
 			using (new PerfTimer("LoadMaps"))
-				ModData.MapCache.LoadMaps(ModData);
+				ModData.MapCache.LoadMaps();
+
+			var grid = ModData.Manifest.Contains<MapGrid>() ? ModData.Manifest.Get<MapGrid>() : null;
+			Renderer.InitializeDepthBuffer(grid);
 
 			Cursor?.Dispose();
-			Cursor = new CursorManager(ModData);
+			Cursor = new CursorManager(ModData.CursorProvider, ModData.Manifest.CursorSheetSize);
 
 			var metadata = ModData.Manifest.Metadata;
 			if (!string.IsNullOrEmpty(metadata.WindowTitleTranslated))
@@ -531,16 +514,10 @@ namespace OpenRA
 			ModData.LoadScreen.StartGame(args);
 		}
 
-		public static void LoadEditor(string uid)
+		public static void LoadEditor(string mapUid)
 		{
 			JoinLocal();
-			StartGame(uid, WorldType.Editor);
-		}
-
-		public static void LoadEditor(Map map)
-		{
-			JoinLocal();
-			StartGame(map, WorldType.Editor);
+			StartGame(mapUid, WorldType.Editor);
 		}
 
 		public static void LoadShellMap()
@@ -614,7 +591,7 @@ namespace OpenRA
 				Directory.CreateDirectory(directory);
 
 				var filename = TimestampedFilename(true);
-				var path = Path.Combine(directory, $"{filename}.png");
+				var path = Path.Combine(directory, string.Concat(filename, ".png"));
 				Log.Write("debug", "Taking screenshot " + path);
 
 				Renderer.SaveScreenshot(path);
@@ -661,7 +638,7 @@ namespace OpenRA
 
 						world.Tick();
 
-						PerfHistory.Tick(!world.Paused);
+						PerfHistory.Tick();
 					}
 
 					// Wait until we have done our first world Tick before TickRendering
@@ -725,7 +702,7 @@ namespace OpenRA
 				// Use worldRenderer.World instead of OrderManager.World to avoid a rendering mismatch while processing orders
 				if (worldRenderer != null && !worldRenderer.World.IsLoadingGameSave)
 				{
-					Renderer.BeginWorld(worldRenderer.Viewport.CenterLocation, worldRenderer.Viewport.ViewportSize);
+					Renderer.BeginWorld(worldRenderer.Viewport.Rectangle);
 					Sound.SetListenerPosition(worldRenderer.Viewport.CenterPosition);
 					using (new PerfSample("render_world"))
 						worldRenderer.Draw();
@@ -740,12 +717,15 @@ namespace OpenRA
 
 					Ui.Draw();
 
+					if (ModData != null && ModData.CursorProvider != null)
+					{
 						if (HideCursor)
-						Cursor?.SetCursor(null);
+							Cursor.SetCursor(null);
 						else
 						{
-						Cursor?.SetCursor(Ui.Root.GetCursorOuter(Viewport.LastMousePos) ?? "default");
-						Cursor?.Render(Renderer);
+							Cursor.SetCursor(Ui.Root.GetCursorOuter(Viewport.LastMousePos) ?? "default");
+							Cursor.Render(Renderer);
+						}
 					}
 				}
 
@@ -759,13 +739,12 @@ namespace OpenRA
 				}
 			}
 
-			var isActive = !(worldRenderer?.World.Paused ?? true);
-			PerfHistory.Items["render"].Tick(isActive);
-			PerfHistory.Items["batches"].Tick(isActive);
-			PerfHistory.Items["render_world"].Tick(isActive);
-			PerfHistory.Items["render_widgets"].Tick(isActive);
-			PerfHistory.Items["render_flip"].Tick(isActive);
-			PerfHistory.Items["terrain_lighting"].Tick(isActive);
+			PerfHistory.Items["render"].Tick();
+			PerfHistory.Items["batches"].Tick();
+			PerfHistory.Items["render_world"].Tick();
+			PerfHistory.Items["render_widgets"].Tick();
+			PerfHistory.Items["render_flip"].Tick();
+			PerfHistory.Items["terrain_lighting"].Tick();
 		}
 
 		static void Loop()
@@ -862,13 +841,8 @@ namespace OpenRA
 
 					var haveSomeTimeUntilNextLogic = now < nextLogic;
 					var isTimeToRender = now >= nextRender;
-					if (!Renderer.WindowIsSuspended)
+					if (!Renderer.WindowIsSuspended && ((isTimeToRender && haveSomeTimeUntilNextLogic) || forceRender))
 					{
-						if (isTimeToRender || forceRender)
-						{
-							if (haveSomeTimeUntilNextLogic || forceRender)
-								RenderTick();
-
 						nextRender = now + renderInterval;
 
 						// Pick the minimum allowed FPS (the lower between 'minReplayFPS'
@@ -879,13 +853,12 @@ namespace OpenRA
 						var maxRenderInterval = Math.Max(1000 / MinReplayFps, renderInterval);
 						forcedNextRender = now + maxRenderInterval;
 
+						RenderTick();
 						renderBeforeNextTick = false;
 					}
-					}
-					else
-					{
+
 					// Simulate a render tick if it was time to render but we skip actually rendering
-						if (isTimeToRender || forceRender)
+					if (Renderer.WindowIsSuspended && isTimeToRender)
 					{
 						// Make sure that nextUpdate is set to a proper minimum interval
 						nextRender = now + renderInterval;
@@ -896,12 +869,6 @@ namespace OpenRA
 						// Ensure that we still logic tick despite not rendering
 						renderBeforeNextTick = false;
 					}
-						else
-						{
-							// Avoid busy wait.
-							Thread.Sleep((int)(nextRender - now));
-						}
-					}
 				}
 				else
 					Thread.Sleep((int)(nextUpdate - now));
@@ -980,8 +947,7 @@ namespace OpenRA
 			{
 				Name = "Skirmish Game",
 				Map = map,
-				AdvertiseOnline = false,
-				AdvertiseOnLocalNetwork = !isSkirmish
+				AdvertiseOnline = false
 			};
 
 			// Always connect to local games using the same loopback connection
@@ -1019,7 +985,7 @@ namespace OpenRA
 				Order.Command($"state {Session.ClientState.Ready}")
 			};
 
-			var map = ModData.MapCache.SingleOrDefault(m => m.Uid == launchMap || Path.GetFileName(m.Path) == launchMap);
+			var map = ModData.MapCache.SingleOrDefault(m => m.Uid == launchMap || Path.GetFileName(m.PackageName) == launchMap);
 			if (map == null)
 				throw new ArgumentException($"Could not find map '{launchMap}'.");
 

OpenRA.Game/GameInformation.cs

@@ -10,7 +10,6 @@
 #endregion
 
 using System;
-using System.Collections.Frozen;
 using System.Collections.Generic;
 using System.Linq;
 using OpenRA.Network;
@@ -40,32 +39,17 @@ namespace OpenRA
 		public TimeSpan Duration => EndTimeUtc > StartTimeUtc ? EndTimeUtc - StartTimeUtc : TimeSpan.Zero;
 
 		public IList<Player> Players { get; }
-		public FrozenSet<int> DisabledSpawnPoints = FrozenSet<int>.Empty;
-
+		public HashSet<int> DisabledSpawnPoints = new();
+		public MapPreview MapPreview => Game.ModData.MapCache[MapUid];
 		public IEnumerable<Player> HumanPlayers { get { return Players.Where(p => p.IsHuman); } }
 		public bool IsSinglePlayer => HumanPlayers.Count() == 1;
 
-		[FieldLoader.Ignore]
-		public MapGenerationArgs MapGenerationArgs;
-
 		readonly Dictionary<OpenRA.Player, Player> playersByRuntime;
 
 		public GameInformation()
 		{
-			Players = [];
-			playersByRuntime = [];
-		}
-
-		public MapPreview GetMapPreview(ModData modData)
-		{
-			var preview = modData.MapCache[MapUid];
-			if (preview.Status != MapStatus.Available && MapGenerationArgs != null)
-			{
-				preview.UpdateFromGenerationArgs(MapGenerationArgs);
-				preview.Generate();
-			}
-
-			return preview;
+			Players = new List<Player>();
+			playersByRuntime = new Dictionary<OpenRA.Player, Player>();
 		}
 
 		public static GameInformation Deserialize(string data, string path)
@@ -88,10 +72,6 @@ namespace OpenRA
 						case "Player":
 							info.Players.Add(FieldLoader.Load<Player>(node.Value));
 							break;
-
-						case "MapGenerationArgs":
-							info.MapGenerationArgs = FieldLoader.Load<MapGenerationArgs>(node.Value);
-							break;
 					}
 				}
 
@@ -114,18 +94,17 @@ namespace OpenRA
 			for (var i = 0; i < Players.Count; i++)
 				nodes.Add(new MiniYamlNode($"Player@{i}", FieldSaver.Save(Players[i])));
 
-			if (MapGenerationArgs != null)
-				nodes.Add(new MiniYamlNode("MapGenerationArgs", new MiniYaml("", MapGenerationArgs.Serialize())));
-
 			return nodes.WriteToString();
 		}
 
 		/// <summary>Adds the player information at start-up.</summary>
 		public void AddPlayer(OpenRA.Player runtimePlayer, Session lobbyInfo)
 		{
-			ArgumentNullException.ThrowIfNull(runtimePlayer);
+			if (runtimePlayer == null)
+				throw new ArgumentNullException(nameof(runtimePlayer));
 
-			ArgumentNullException.ThrowIfNull(lobbyInfo);
+			if (lobbyInfo == null)
+				throw new ArgumentNullException(nameof(lobbyInfo));
 
 			// We don't care about spectators and map players
 			if (runtimePlayer.NonCombatant || !runtimePlayer.Playable)

OpenRA.Game/GameRules/ActorInfo.cs

@@ -32,7 +32,7 @@ namespace OpenRA
 		/// You can remove inherited traits by adding a - in front of them as in -TraitName: to inherit everything, but this trait.
 		/// </summary>
 		public readonly string Name;
-		readonly TypeDictionary traits = [];
+		readonly TypeDictionary traits = new();
 		TraitInfo[] constructOrderCache = null;
 
 		public ActorInfo(ObjectCreator creator, string name, MiniYaml node)

OpenRA.Game/GameRules/Ruleset.cs

@@ -11,7 +11,6 @@
 
 using System;
 using System.Collections.Generic;
-using System.Collections.Immutable;
 using System.Linq;
 using System.Threading.Tasks;
 using OpenRA.FileSystem;
@@ -269,7 +268,7 @@ namespace OpenRA
 
 			if (mapRules.Value != null)
 			{
-				var mapFiles = FieldLoader.GetValue<ImmutableArray<string>>("value", mapRules.Value);
+				var mapFiles = FieldLoader.GetValue<string[]>("value", mapRules.Value);
 				foreach (var f in mapFiles)
 					if (AnyFlaggedTraits(modData, MiniYaml.FromStream(fileSystem.Open(f), f)))
 						return true;

OpenRA.Game/GameRules/SoundInfo.cs

@@ -10,38 +10,37 @@
 #endregion
 
 using System;
-using System.Collections.Frozen;
 using System.Collections.Generic;
-using System.Collections.Immutable;
+using System.Linq;
 
 namespace OpenRA.GameRules
 {
 	public class SoundInfo
 	{
-		public readonly FrozenDictionary<string, ImmutableArray<string>> Variants = FrozenDictionary<string, ImmutableArray<string>>.Empty;
-		public readonly FrozenDictionary<string, ImmutableArray<string>> Prefixes = FrozenDictionary<string, ImmutableArray<string>>.Empty;
-		public readonly FrozenDictionary<string, ImmutableArray<string>> Voices = FrozenDictionary<string, ImmutableArray<string>>.Empty;
-		public readonly FrozenDictionary<string, ImmutableArray<string>> Notifications = FrozenDictionary<string, ImmutableArray<string>>.Empty;
+		public readonly Dictionary<string, string[]> Variants = new();
+		public readonly Dictionary<string, string[]> Prefixes = new();
+		public readonly Dictionary<string, string[]> Voices = new();
+		public readonly Dictionary<string, string[]> Notifications = new();
 		public readonly string DefaultVariant = ".aud";
 		public readonly string DefaultPrefix = "";
-		public readonly FrozenSet<string> DisableVariants = FrozenSet<string>.Empty;
-		public readonly FrozenSet<string> DisablePrefixes = FrozenSet<string>.Empty;
+		public readonly HashSet<string> DisableVariants = new();
+		public readonly HashSet<string> DisablePrefixes = new();
 
-		public readonly Lazy<FrozenDictionary<string, SoundPool>> VoicePools;
-		public readonly Lazy<FrozenDictionary<string, SoundPool>> NotificationsPools;
+		public readonly Lazy<Dictionary<string, SoundPool>> VoicePools;
+		public readonly Lazy<Dictionary<string, SoundPool>> NotificationsPools;
 
 		public SoundInfo(MiniYaml y)
 		{
 			FieldLoader.Load(this, y);
 
-			VoicePools = Exts.Lazy(() => Voices.ToFrozenDictionary(a => a.Key, a => new SoundPool(1f, SoundPool.DefaultInterruptType, a.Value)));
+			VoicePools = Exts.Lazy(() => Voices.ToDictionary(a => a.Key, a => new SoundPool(1f, SoundPool.DefaultInterruptType, a.Value)));
 			NotificationsPools = Exts.Lazy(() => ParseSoundPool(y, "Notifications"));
 		}
 
-		static FrozenDictionary<string, SoundPool> ParseSoundPool(MiniYaml y, string key)
+		static Dictionary<string, SoundPool> ParseSoundPool(MiniYaml y, string key)
 		{
+			var ret = new Dictionary<string, SoundPool>();
 			var classifiction = y.NodeWithKey(key);
-			var ret = new Dictionary<string, SoundPool>(classifiction.Value.Nodes.Length);
 			foreach (var t in classifiction.Value.Nodes)
 			{
 				var volumeModifier = 1f;
@@ -54,12 +53,12 @@ namespace OpenRA.GameRules
 				if (interruptTypeNode != null)
 					interruptType = FieldLoader.GetValue<SoundPool.InterruptType>(interruptTypeNode.Key, interruptTypeNode.Value.Value);
 
-				var names = FieldLoader.GetValue<ImmutableArray<string>>(t.Key, t.Value.Value);
+				var names = FieldLoader.GetValue<string[]>(t.Key, t.Value.Value);
 				var sp = new SoundPool(volumeModifier, interruptType, names);
 				ret.Add(t.Key, sp);
 			}
 
-			return ret.ToFrozenDictionary();
+			return ret;
 		}
 	}
 
@@ -69,10 +68,10 @@ namespace OpenRA.GameRules
 		public const InterruptType DefaultInterruptType = InterruptType.DoNotPlay;
 		public readonly float VolumeModifier;
 		public readonly InterruptType Type;
-		readonly ImmutableArray<string> clips;
-		readonly List<string> liveclips = [];
+		readonly string[] clips;
+		readonly List<string> liveclips = new();
 
-		public SoundPool(float volumeModifier, InterruptType interruptType, ImmutableArray<string> clips)
+		public SoundPool(float volumeModifier, InterruptType interruptType, params string[] clips)
 		{
 			VolumeModifier = volumeModifier;
 			Type = interruptType;

OpenRA.Game/GameRules/WeaponInfo.cs

@@ -11,7 +11,6 @@
 
 using System;
 using System.Collections.Generic;
-using System.Collections.Immutable;
 using System.Linq;
 using OpenRA.Effects;
 using OpenRA.Primitives;
@@ -37,7 +36,7 @@ namespace OpenRA.GameRules
 	public class WarheadArgs
 	{
 		public WeaponInfo Weapon;
-		public int[] DamageModifiers = [];
+		public int[] DamageModifiers = Array.Empty<int>();
 		public WPos? Source;
 		public WRot ImpactOrientation;
 		public WPos ImpactPosition;
@@ -83,13 +82,13 @@ namespace OpenRA.GameRules
 		public readonly WVec FollowingBurstTargetOffset = WVec.Zero;
 
 		[Desc("The sound played each time the weapon is fired.")]
-		public readonly ImmutableArray<string> Report = default;
+		public readonly string[] Report = null;
 
 		[Desc("Sound played only on first burst in a salvo.")]
-		public readonly ImmutableArray<string> StartBurstReport = default;
+		public readonly string[] StartBurstReport = null;
 
 		[Desc("The sound played when the weapon is reloaded.")]
-		public readonly ImmutableArray<string> AfterFireSound = default;
+		public readonly string[] AfterFireSound = null;
 
 		[Desc("Delay in ticks to play reloading sound.")]
 		public readonly int AfterFireSoundDelay = 0;
@@ -117,7 +116,7 @@ namespace OpenRA.GameRules
 
 		[Desc("Delay in ticks between firing shots from the same ammo magazine. If one entry, it will be used for all bursts.",
 			"If multiple entries, their number needs to match Burst - 1.")]
-		public readonly ImmutableArray<int> BurstDelays = [5];
+		public readonly int[] BurstDelays = { 5 };
 
 		[Desc("The minimum range the weapon can fire.")]
 		public readonly WDist MinRange = WDist.Zero;
@@ -129,7 +128,7 @@ namespace OpenRA.GameRules
 		public readonly IProjectileInfo Projectile;
 
 		[FieldLoader.LoadUsing(nameof(LoadWarheads))]
-		public readonly ImmutableArray<IWarhead> Warheads = [];
+		public readonly List<IWarhead> Warheads = new();
 
 		/// <summary>
 		/// This constructor is used solely for documentation generation.
@@ -140,7 +139,7 @@ namespace OpenRA.GameRules
 		{
 			// Resolve any weapon-level yaml inheritance or removals
 			// HACK: The "Defaults" sequence syntax prevents us from doing this generally during yaml parsing
-			content = content.WithNodes(MiniYaml.Merge([content.Nodes]));
+			content = content.WithNodes(MiniYaml.Merge(new IReadOnlyCollection<MiniYamlNode>[] { content.Nodes }));
 			FieldLoader.Load(this, content);
 		}
 
@@ -171,7 +170,7 @@ namespace OpenRA.GameRules
 				retList.Add(ret);
 			}
 
-			return retList.ToImmutableArray();
+			return retList;
 		}
 
 		public bool IsValidTarget(BitSet<TargetableType> targetTypes)

OpenRA.Game/GameSpeed.cs

@@ -10,7 +10,6 @@
 #endregion
 
 using System.Collections.Generic;
-using OpenRA.Traits;
 
 namespace OpenRA
 {
@@ -32,7 +31,6 @@ namespace OpenRA
 		[FieldLoader.Require]
 		public readonly string DefaultSpeed;
 
-		[IncludeFluentReferences(LintDictionaryReference.Values)]
 		[FieldLoader.LoadUsing(nameof(LoadSpeeds))]
 		public readonly Dictionary<string, GameSpeed> Speeds;
 

OpenRA.Game/Graphics/Animation.cs

@@ -10,7 +10,6 @@
 #endregion
 
 using System;
-using System.Collections.Immutable;
 using System.Linq;
 using OpenRA.Primitives;
 using OpenRA.Support;
@@ -74,10 +73,10 @@ namespace OpenRA.Graphics
 					shadow, pos, offset - new WVec(0, 0, height), CurrentSequence.ShadowZOffset + zOffset + height, palette,
 					CurrentSequence.Scale, 1f, float3.Ones, tintModifiers,
 					true, rotation);
-				return [shadowRenderable, imageRenderable];
+				return new IRenderable[] { shadowRenderable, imageRenderable };
 			}
 
-			return [imageRenderable];
+			return new IRenderable[] { imageRenderable };
 		}
 
 		public IRenderable[] RenderUI(WorldRenderer wr, int2 pos, in WVec offset, int zOffset, PaletteReference palette, float scale = 1f, float rotation = 0f)
@@ -93,10 +92,10 @@ namespace OpenRA.Graphics
 			{
 				var shadowPos = pos - new int2((int)(scale * shadow.Size.X / 2), (int)(scale * shadow.Size.Y / 2));
 				var shadowRenderable = new UISpriteRenderable(shadow, WPos.Zero + offset, shadowPos, CurrentSequence.ShadowZOffset + zOffset, palette, scale, 1f, rotation);
-				return [shadowRenderable, imageRenderable];
+				return new IRenderable[] { shadowRenderable, imageRenderable };
 			}
 
-			return [imageRenderable];
+			return new IRenderable[] { imageRenderable };
 		}
 
 		public Rectangle ScreenBounds(WorldRenderer wr, WPos pos, in WVec offset)
@@ -251,9 +250,9 @@ namespace OpenRA.Graphics
 			return sequences.GetSequence(Name, sequenceName);
 		}
 
-		public string GetRandomExistingSequence(ImmutableArray<string> sequences, MersenneTwister random)
+		public string GetRandomExistingSequence(string[] sequences, MersenneTwister random)
 		{
-			return sequences.Where(HasSequence).RandomOrDefault(random);
+			return sequences.Where(s => HasSequence(s)).RandomOrDefault(random);
 		}
 	}
 }

OpenRA.Game/Graphics/ChromeProvider.cs

@@ -10,9 +10,7 @@
 #endregion
 
 using System;
-using System.Collections.Frozen;
 using System.Collections.Generic;
-using System.Collections.Immutable;
 using System.Linq;
 using OpenRA.FileSystem;
 using OpenRA.Primitives;
@@ -49,9 +47,9 @@ namespace OpenRA.Graphics
 			public readonly string Image2x = null;
 			public readonly string Image3x = null;
 
-			public readonly ImmutableArray<int> PanelRegion = default;
+			public readonly int[] PanelRegion = null;
 			public readonly PanelSides PanelSides = PanelSides.All;
-			public readonly FrozenDictionary<string, Rectangle> Regions = FrozenDictionary<string, Rectangle>.Empty;
+			public readonly Dictionary<string, Rectangle> Regions = new();
 		}
 
 		public static IReadOnlyDictionary<string, Collection> Collections => collections;
@@ -73,11 +71,11 @@ namespace OpenRA.Graphics
 				dpiScale = Game.Renderer.WindowScale;
 
 			fileSystem = modData.DefaultFileSystem;
-			collections = [];
-			cachedSheets = [];
-			cachedSprites = [];
-			cachedPanelSprites = [];
-			cachedCollectionSheets = [];
+			collections = new Dictionary<string, Collection>();
+			cachedSheets = new Dictionary<string, (Sheet, int)>();
+			cachedSprites = new Dictionary<string, Dictionary<string, Sprite>>();
+			cachedPanelSprites = new Dictionary<string, Sprite[]>();
+			cachedCollectionSheets = new Dictionary<Collection, (Sheet, int)>();
 
 			var stringPool = new HashSet<string>(); // Reuse common strings in YAML
 			var chrome = MiniYaml.Merge(modData.Manifest.Chrome
@@ -172,7 +170,7 @@ namespace OpenRA.Graphics
 			var sheetDensity = SheetForCollection(collection);
 			if (cachedCollection == null)
 			{
-				cachedCollection = [];
+				cachedCollection = new Dictionary<string, Sprite>();
 				cachedSprites.Add(collectionName, cachedCollection);
 			}
 
@@ -242,11 +240,11 @@ namespace OpenRA.Graphics
 				// PERF: We don't need to search for images if there are no definitions.
 				// PERF: It's more efficient to send an empty array rather than an array of 9 nulls.
 				if (collection.Regions.Count == 0)
-					return [];
+					return Array.Empty<Sprite>();
 
 				// Support manual definitions for unusual dialog layouts
-				sprites =
-				[
+				sprites = new[]
+				{
 					TryGetImage(collectionName, "corner-tl"),
 					TryGetImage(collectionName, "border-t"),
 					TryGetImage(collectionName, "corner-tr"),
@@ -256,7 +254,7 @@ namespace OpenRA.Graphics
 					TryGetImage(collectionName, "corner-bl"),
 					TryGetImage(collectionName, "border-b"),
 					TryGetImage(collectionName, "corner-br")
-				];
+				};
 			}
 
 			cachedPanelSprites.Add(collectionName, sprites);

OpenRA.Game/Graphics/CursorManager.cs

@@ -13,7 +13,6 @@ using System;
 using System.Collections.Generic;
 using System.Linq;
 using OpenRA.Primitives;
-using OpenRA.Traits;
 
 namespace OpenRA.Graphics
 {
@@ -30,8 +29,8 @@ namespace OpenRA.Graphics
 			public IHardwareCursor[] Cursors;
 		}
 
-		readonly Dictionary<string, Cursor> cursors = [];
-		public readonly SheetBuilder SheetBuilder;
+		readonly Dictionary<string, Cursor> cursors = new();
+		readonly SheetBuilder sheetBuilder;
 		readonly GraphicSettings graphicSettings;
 
 		Cursor cursor;
@@ -40,35 +39,19 @@ namespace OpenRA.Graphics
 		readonly bool hardwareCursorsDisabled = false;
 		bool hardwareCursorsDoubled = false;
 
-		public CursorManager(ModData modData)
+		public CursorManager(CursorProvider cursorProvider, int cursorSheetSize)
 		{
+			hardwareCursorsDisabled = Game.Settings.Graphics.DisableHardwareCursors;
+
 			graphicSettings = Game.Settings.Graphics;
-			hardwareCursorsDisabled = graphicSettings.DisableHardwareCursors;
-			SheetBuilder = new SheetBuilder(SheetType.BGRA, modData.Manifest.RendererConstants.CursorSheetSize);
-
-			// Overwrite previous definitions if there are duplicates
-			var pals = new Dictionary<string, IProvidesCursorPaletteInfo>();
-			foreach (var p in modData.DefaultRules.Actors[SystemActors.World].TraitInfos<IProvidesCursorPaletteInfo>())
-				if (p.Palette != null)
-					pals[p.Palette] = p;
-
-			var paletteCache = new Cache<string, ImmutablePalette>(p => pals[p].ReadPalette(modData.DefaultFileSystem));
-			var frameCache = new FrameCache(modData.DefaultFileSystem, modData.SpriteLoaders);
+			sheetBuilder = new SheetBuilder(SheetType.BGRA, cursorSheetSize);
 
 			// Sort the cursors for better packing onto the sheet.
-			foreach (var kv in modData.Cursors)
+			foreach (var kv in cursorProvider.Cursors
+				.OrderBy(kvp => kvp.Value.Frames.Max(f => f.Size.Height)))
 			{
-				var cursorSprites = frameCache[kv.Value.Src];
-				var length = kv.Value.Length ?? cursorSprites.Length - kv.Value.Start;
-
-				if (kv.Value.Start > cursorSprites.Length)
-					throw new YamlException($"Cursor {kv.Value.Name}: {nameof(kv.Value.Start)} is greater than the length of the sprite sequence.");
-
-				if (kv.Value.Length > cursorSprites.Length)
-					throw new YamlException($"Cursor {kv.Value.Name}: {nameof(kv.Value.Length)} is greater than the length of the sprite sequence.");
-
-				var frames = cursorSprites.Skip(kv.Value.Start).Take(length).ToArray();
-				var palette = !string.IsNullOrEmpty(kv.Value.Palette) ? paletteCache[kv.Value.Palette] : null;
+				var frames = kv.Value.Frames;
+				var palette = !string.IsNullOrEmpty(kv.Value.Palette) ? cursorProvider.Palettes[kv.Value.Palette] : null;
 
 				var c = new Cursor
 				{
@@ -99,7 +82,7 @@ namespace OpenRA.Graphics
 						type = SpriteFrameType.Bgra32;
 					}
 
-					c.Sprites[c.Length++] = SheetBuilder.Add(data, type, f.Size, 0, hotspot);
+					c.Sprites[c.Length++] = sheetBuilder.Add(data, type, f.Size, 0, hotspot);
 
 					// Bounds relative to the hotspot
 					c.Bounds = Rectangle.Union(c.Bounds, new Rectangle(hotspot, f.Size));
@@ -111,13 +94,9 @@ namespace OpenRA.Graphics
 				cursors.Add(kv.Key, c);
 			}
 
-			// Allow the utility to create a cursor manager.
-			if (Game.Renderer != null)
-			{
 			CreateOrUpdateHardwareCursors();
 			Update();
 		}
-		}
 
 		void CreateOrUpdateHardwareCursors()
 		{
@@ -149,7 +128,7 @@ namespace OpenRA.Graphics
 				}
 			}
 
-			SheetBuilder.Current?.ReleaseBuffer();
+			sheetBuilder.Current.ReleaseBuffer();
 
 			hardwareCursorsDoubled = graphicSettings.CursorDouble;
 		}
@@ -254,7 +233,7 @@ namespace OpenRA.Graphics
 			var height = frame.Size.Height;
 
 			if (width == 0 || height == 0)
-				return [];
+				return Array.Empty<byte>();
 
 			var data = new byte[4 * width * height];
 			unsafe
@@ -300,18 +279,21 @@ namespace OpenRA.Graphics
 			{
 				for (var i = 0; i < c.Cursors.Length; i++)
 				{
-					c.Cursors[i]?.Dispose();
+					if (c.Cursors[i] != null)
+					{
+						c.Cursors[i].Dispose();
 						c.Cursors[i] = null;
 					}
 				}
 			}
+		}
 
 		public void Dispose()
 		{
 			ClearHardwareCursors();
 
 			cursors.Clear();
-			SheetBuilder.Dispose();
+			sheetBuilder.Dispose();
 		}
 	}
 }

OpenRA.Game/Graphics/CursorProvider.cs

@@ -0,0 +1,67 @@
+#region Copyright & License Information
+/*
+ * Copyright (c) The OpenRA Developers and Contributors
+ * This file is part of OpenRA, which is free software. It is made
+ * available to you under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, either version 3 of
+ * the License, or (at your option) any later version. For more
+ * information, see COPYING.
+ */
+#endregion
+
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using OpenRA.Traits;
+
+namespace OpenRA.Graphics
+{
+	public sealed class CursorProvider
+	{
+		public readonly IReadOnlyDictionary<string, CursorSequence> Cursors;
+		public readonly IReadOnlyDictionary<string, ImmutablePalette> Palettes;
+
+		public CursorProvider(ModData modData)
+		{
+			var fileSystem = modData.DefaultFileSystem;
+			var stringPool = new HashSet<string>(); // Reuse common strings in YAML
+			var sequenceYaml = MiniYaml.Merge(modData.Manifest.Cursors.Select(
+				s => MiniYaml.FromStream(fileSystem.Open(s), s, stringPool: stringPool)));
+
+			var cursorsYaml = new MiniYaml(null, sequenceYaml).NodeWithKey("Cursors").Value;
+
+			// Overwrite previous definitions if there are duplicates
+			var pals = new Dictionary<string, IProvidesCursorPaletteInfo>();
+			foreach (var p in modData.DefaultRules.Actors[SystemActors.World].TraitInfos<IProvidesCursorPaletteInfo>())
+				if (p.Palette != null)
+					pals[p.Palette] = p;
+
+			Palettes = cursorsYaml.Nodes.Select(n => n.Value.Value)
+				.Where(p => p != null)
+				.Distinct()
+				.ToDictionary(p => p, p => pals[p].ReadPalette(modData.DefaultFileSystem));
+
+			var frameCache = new FrameCache(fileSystem, modData.SpriteLoaders);
+			var cursors = new Dictionary<string, CursorSequence>();
+			foreach (var s in cursorsYaml.Nodes)
+				foreach (var sequence in s.Value.Nodes)
+					cursors.Add(sequence.Key, new CursorSequence(frameCache, sequence.Key, s.Key, s.Value.Value, sequence.Value));
+
+			Cursors = cursors;
+		}
+
+		public bool HasCursorSequence(string cursor)
+		{
+			return Cursors.ContainsKey(cursor);
+		}
+
+		public CursorSequence GetCursorSequence(string cursor)
+		{
+			try { return Cursors[cursor]; }
+			catch (KeyNotFoundException)
+			{
+				throw new InvalidOperationException($"Cursor does not have a sequence `{cursor}`");
+			}
+		}
+	}
+}

OpenRA.Game/Graphics/CursorSequence.cs

@@ -9,26 +9,50 @@
  */
 #endregion
 
+using System.Linq;
+
 namespace OpenRA.Graphics
 {
 	public class CursorSequence
 	{
 		public readonly string Name;
-		public readonly string Src;
 		public readonly int Start;
-		public readonly int? Length;
+		public readonly int Length;
 		public readonly string Palette;
 		public readonly int2 Hotspot;
 
-		public CursorSequence(string name, string cursorSrc, string palette, MiniYaml info)
+		public readonly ISpriteFrame[] Frames;
+
+		public CursorSequence(FrameCache cache, string name, string cursorSrc, string palette, MiniYaml info)
 		{
 			var d = info.ToDictionary();
 
+			Start = Exts.ParseInt32Invariant(d["Start"].Value);
 			Palette = palette;
 			Name = name;
-			Src = cursorSrc;
 
-			if (d.TryGetValue("X", out var yaml))
+			var cursorSprites = cache[cursorSrc];
+			Frames = cursorSprites.Skip(Start).ToArray();
+
+			if ((d.TryGetValue("Length", out var yaml) && yaml.Value == "*") ||
+				(d.TryGetValue("End", out yaml) && yaml.Value == "*"))
+				Length = Frames.Length;
+			else if (d.TryGetValue("Length", out yaml))
+				Length = Exts.ParseInt32Invariant(yaml.Value);
+			else if (d.TryGetValue("End", out yaml))
+				Length = Exts.ParseInt32Invariant(yaml.Value) - Start;
+			else
+				Length = 1;
+
+			Frames = Frames.Take(Length).ToArray();
+
+			if (Start > cursorSprites.Length)
+				throw new YamlException($"Cursor {name}: {nameof(Start)} is greater than the length of the sprite sequence.");
+
+			if (Length > cursorSprites.Length)
+				throw new YamlException($"Cursor {name}: {nameof(Length)} is greater than the length of the sprite sequence.");
+
+			if (d.TryGetValue("X", out yaml))
 			{
 				Exts.TryParseInt32Invariant(yaml.Value, out var x);
 				Hotspot = Hotspot.WithX(x);
@@ -39,14 +63,6 @@ namespace OpenRA.Graphics
 				Exts.TryParseInt32Invariant(yaml.Value, out var y);
 				Hotspot = Hotspot.WithY(y);
 			}
-
-			Start = Exts.ParseInt32Invariant(d["Start"].Value);
-			if (d.TryGetValue("Length", out yaml))
-				Length = yaml.Value != "*" ? Exts.ParseInt32Invariant(yaml.Value) : null;
-			else if (d.TryGetValue("End", out yaml) && yaml.Value == "*")
-				Length = yaml.Value != "*" ? Exts.ParseInt32Invariant(yaml.Value) - Start : null;
-			else
-				Length = 1;
 		}
 	}
 }

OpenRA.Game/Graphics/HardwarePalette.cs

@@ -21,11 +21,11 @@ namespace OpenRA.Graphics
 		public ITexture ColorShifts { get; }
 
 		public int Height { get; private set; }
-		readonly Dictionary<string, ImmutablePalette> palettes = [];
-		readonly Dictionary<string, MutablePalette> mutablePalettes = [];
-		readonly Dictionary<string, int> indices = [];
-		byte[] buffer = [];
-		float[] colorShiftBuffer = [];
+		readonly Dictionary<string, ImmutablePalette> palettes = new();
+		readonly Dictionary<string, MutablePalette> mutablePalettes = new();
+		readonly Dictionary<string, int> indices = new();
+		byte[] buffer = Array.Empty<byte>();
+		float[] colorShiftBuffer = Array.Empty<float>();
 
 		public HardwarePalette()
 		{

OpenRA.Game/Graphics/Model.cs

@@ -31,13 +31,25 @@ namespace OpenRA.Graphics
 
 	public interface IModelWidget
 	{
-		string Palette { get; }
-		float Scale { get; }
-		void Setup(Func<bool> isVisible, Func<string> getPalette, Func<string> getPlayerPalette,
+		public string Palette { get; }
+		public float Scale { get; }
+		public void Setup(Func<bool> isVisible, Func<string> getPalette, Func<string> getPlayerPalette,
 			Func<float> getScale, Func<IModel> getVoxel, Func<WRot> getRotation);
 	}
 
-	public readonly record struct ModelRenderData(int Start, int Count, Sheet Sheet);
+	public readonly struct ModelRenderData
+	{
+		public readonly int Start;
+		public readonly int Count;
+		public readonly Sheet Sheet;
+
+		public ModelRenderData(int start, int count, Sheet sheet)
+		{
+			Start = start;
+			Count = count;
+			Sheet = sheet;
+		}
+	}
 
 	public interface IModelCacheInfo : ITraitInfoInterface { }
 

OpenRA.Game/Graphics/ModelVertex.cs

@@ -43,11 +43,11 @@ namespace OpenRA.Graphics
 			: base("model")
 		{ }
 
-		public override ShaderVertexAttribute[] Attributes { get; } =
-		[
+		public override ShaderVertexAttribute[] Attributes { get; } = new[]
+		{
 			new ShaderVertexAttribute("aVertexPosition", ShaderVertexAttributeType.Float, 3, 0),
 			new ShaderVertexAttribute("aVertexTexCoord", ShaderVertexAttributeType.Float, 4, 12),
 			new ShaderVertexAttribute("aVertexTexMetadata", ShaderVertexAttributeType.Float, 2, 28),
-		];
+		};
 	}
 }

OpenRA.Game/Graphics/Palette.cs

@@ -11,7 +11,6 @@
 
 using System;
 using System.Collections.Generic;
-using System.Collections.Immutable;
 using System.IO;
 using OpenRA.Primitives;
 
@@ -65,18 +64,18 @@ namespace OpenRA.Graphics
 			Buffer.BlockCopy(colors, 0, destination, destinationOffset * 4, Palette.Size * 4);
 		}
 
-		public ImmutablePalette(string filename, ImmutableArray<int> remapTransparent, ImmutableArray<int> remap)
+		public ImmutablePalette(string filename, int[] remapTransparent, int[] remap)
 		{
 			using (var s = File.OpenRead(filename))
 				LoadFromStream(s, remapTransparent, remap);
 		}
 
-		public ImmutablePalette(Stream s, ImmutableArray<int> remapTransparent, ImmutableArray<int> remapShadow)
+		public ImmutablePalette(Stream s, int[] remapTransparent, int[] remapShadow)
 		{
 			LoadFromStream(s, remapTransparent, remapShadow);
 		}
 
-		void LoadFromStream(Stream s, ImmutableArray<int> remapTransparent, ImmutableArray<int> remapShadow)
+		void LoadFromStream(Stream s, int[] remapTransparent, int[] remapShadow)
 		{
 			using (var reader = new BinaryReader(s))
 				for (var i = 0; i < Palette.Size; i++)

OpenRA.Game/Graphics/PlatformInterfaces.cs

@@ -66,7 +66,6 @@ namespace OpenRA
 		void PumpInput(IInputHandler inputHandler);
 		string GetClipboardText();
 		bool SetClipboardText(string text);
-		bool TryOpenUrl(string url);
 
 		void GrabWindowMouseFocus();
 		void ReleaseWindowMouseFocus();
@@ -84,8 +83,7 @@ namespace OpenRA
 
 	public interface IGraphicsContext : IDisposable
 	{
-		IVertexBuffer<T> CreateEmptyVertexBuffer<T>(int size) where T : struct;
-		IVertexBuffer<T> CreateVertexBuffer<T>(T[] data, bool dynamic = true) where T : struct;
+		IVertexBuffer<T> CreateVertexBuffer<T>(int size) where T : struct;
 		T[] CreateVertices<T>(int size) where T : struct;
 		IIndexBuffer CreateIndexBuffer(uint[] indices);
 		ITexture CreateTexture();
@@ -136,7 +134,7 @@ namespace OpenRA
 		void SetVec(string name, float x);
 		void SetVec(string name, float x, float y);
 		void SetVec(string name, float x, float y, float z);
-		void SetVec(string name, ReadOnlyMemory<float> vec, int length);
+		void SetVec(string name, float[] vec, int length);
 		void SetTexture(string param, ITexture texture);
 		void SetMatrix(string param, float[] mtx);
 		void PrepareRender();
@@ -181,6 +179,12 @@ namespace OpenRA
 		TriangleList,
 	}
 
+	public readonly struct Range<T>
+	{
+		public readonly T Start, End;
+		public Range(T start, T end) { Start = start; End = end; }
+	}
+
 	public enum WindowMode
 	{
 		Windowed,

OpenRA.Game/Graphics/PlayerColorRemap.cs

@@ -10,19 +10,19 @@
 #endregion
 
 using System;
-using System.Collections.Immutable;
+using System.Linq;
 using OpenRA.Primitives;
 
 namespace OpenRA.Graphics
 {
 	public class PlayerColorRemap : IPaletteRemap
 	{
-		readonly ImmutableArray<int> remapIndices;
+		readonly int[] remapIndices;
 		readonly float hue;
 		readonly float saturation;
 		readonly float value;
 
-		public PlayerColorRemap(ImmutableArray<int> remapIndices, Color color)
+		public PlayerColorRemap(int[] remapIndices, Color color)
 		{
 			this.remapIndices = remapIndices;
 

OpenRA.Game/Graphics/RenderPostProcessPassVertex.cs

@@ -14,20 +14,39 @@ using System.Runtime.InteropServices;
 namespace OpenRA.Graphics
 {
 	[StructLayout(LayoutKind.Sequential)]
-	public readonly record struct RenderPostProcessPassVertex(float X, float Y);
+	public readonly struct RenderPostProcessPassVertex
+	{
+		public readonly float X, Y;
+
+		public RenderPostProcessPassVertex(float x, float y)
+		{
+			X = x; Y = y;
+		}
+	}
 
 	[StructLayout(LayoutKind.Sequential)]
-	public readonly record struct RenderPostProcessPassTexturedVertex(float X, float Y, float S, float T);
+	public readonly struct RenderPostProcessPassTexturedVertex
+	{
+		// 3d position
+		public readonly float X, Y;
+		public readonly float S, T;
+
+		public RenderPostProcessPassTexturedVertex(float x, float y, float s, float t)
+		{
+			X = x; Y = y;
+			S = s; T = t;
+		}
+	}
 
 	public sealed class RenderPostProcessPassShaderBindings : ShaderBindings
 	{
 		public RenderPostProcessPassShaderBindings(string name)
 			: base("postprocess", "postprocess_" + name) { }
 
-		public override ShaderVertexAttribute[] Attributes { get; } =
-		[
+		public override ShaderVertexAttribute[] Attributes { get; } = new[]
+		{
 			new ShaderVertexAttribute("aVertexPosition", ShaderVertexAttributeType.Float, 2, 0)
-		];
+		};
 	}
 
 	public sealed class RenderPostProcessPassTexturedShaderBindings : ShaderBindings
@@ -36,10 +55,10 @@ namespace OpenRA.Graphics
 			: base("postprocess_textured", "postprocess_textured_" + name)
 		{ }
 
-		public override ShaderVertexAttribute[] Attributes { get; } =
-		[
+		public override ShaderVertexAttribute[] Attributes { get; } = new[]
+		{
 			new ShaderVertexAttribute("aVertexPosition", ShaderVertexAttributeType.Float, 2, 0),
 			new ShaderVertexAttribute("aVertexTexCoord", ShaderVertexAttributeType.Float, 2, 8),
-		];
+		};
 	}
 }

OpenRA.Game/Graphics/RgbaColorRenderer.cs

@@ -191,7 +191,7 @@ namespace OpenRA.Graphics
 		{
 			var tr = new float3(br.X, tl.Y, tl.Z);
 			var bl = new float3(tl.X, br.Y, br.Z);
-			DrawPolygon([tl, tr, br, bl], width, color, blendMode);
+			DrawPolygon(new[] { tl, tr, br, bl }, width, color, blendMode);
 		}
 
 		public void FillRect(in float3 tl, in float3 br, Color color, BlendMode blendMode = BlendMode.Alpha)

OpenRA.Game/Graphics/SequenceSet.cs

@@ -37,23 +37,23 @@ namespace OpenRA.Graphics
 
 	public interface ISpriteSequenceLoader
 	{
+		int BgraSheetSize { get; }
+		int IndexedSheetSize { get; }
 		IReadOnlyDictionary<string, ISpriteSequence> ParseSequences(ModData modData, string tileSet, SpriteCache cache, MiniYamlNode node);
 	}
 
 	public sealed class SequenceSet : IDisposable
 	{
-		public readonly string TileSet;
 		readonly ModData modData;
+		readonly string tileSet;
 		readonly IReadOnlyDictionary<string, IReadOnlyDictionary<string, ISpriteSequence>> images;
 		public SpriteCache SpriteCache { get; }
 
 		public SequenceSet(IReadOnlyFileSystem fileSystem, ModData modData, string tileSet, MiniYaml additionalSequences)
 		{
 			this.modData = modData;
-			TileSet = tileSet;
-
-			var rc = modData.Manifest.RendererConstants;
-			SpriteCache = new SpriteCache(fileSystem, modData.SpriteLoaders, rc.SequenceBgraSheetSize, rc.SequenceIndexedSheetSize);
+			this.tileSet = tileSet;
+			SpriteCache = new SpriteCache(fileSystem, modData.SpriteLoaders, modData.SpriteSequenceLoader.BgraSheetSize, modData.SpriteSequenceLoader.IndexedSheetSize);
 			using (new Support.PerfTimer("LoadSequences"))
 				images = Load(fileSystem, additionalSequences);
 		}
@@ -97,7 +97,7 @@ namespace OpenRA.Graphics
 				if (node.Key.StartsWith(ActorInfo.AbstractActorPrefix))
 					continue;
 
-				images[node.Key] = modData.SpriteSequenceLoader.ParseSequences(modData, TileSet, SpriteCache, node);
+				images[node.Key] = modData.SpriteSequenceLoader.ParseSequences(modData, tileSet, SpriteCache, node);
 			}
 
 			return images;

OpenRA.Game/Graphics/ShaderBindings.cs

@@ -23,7 +23,21 @@ namespace OpenRA.Graphics
 		UInt = 0x1405 // GL_UNSIGNED_INT
 	}
 
-	public readonly record struct ShaderVertexAttribute(string Name, ShaderVertexAttributeType Type, int Components, int Offset);
+	public readonly struct ShaderVertexAttribute
+	{
+		public readonly string Name;
+		public readonly ShaderVertexAttributeType Type;
+		public readonly int Components;
+		public readonly int Offset;
+
+		public ShaderVertexAttribute(string name, ShaderVertexAttributeType type, int components, int offset)
+		{
+			Name = name;
+			Type = type;
+			Components = components;
+			Offset = offset;
+		}
+	}
 
 	public abstract class ShaderBindings : IShaderBindings
 	{

OpenRA.Game/Graphics/Sheet.cs

@@ -149,7 +149,7 @@ namespace OpenRA.Graphics
 			var buffer = data;
 			ReleaseBuffer();
 
-			// We aren't committing data to the GPU, so let's not delete our data.
+			// We aren't commiting data to the GPU, so let's not delete our data.
 			if (Game.Renderer == null)
 				return false;
 

OpenRA.Game/Graphics/SheetBuilder.cs

@@ -16,6 +16,7 @@ using OpenRA.Primitives;
 
 namespace OpenRA.Graphics
 {
+	[Serializable]
 	public class SheetOverflowException : Exception
 	{
 		public SheetOverflowException(string message)
@@ -33,7 +34,7 @@ namespace OpenRA.Graphics
 	public sealed class SheetBuilder : IDisposable
 	{
 		public readonly SheetType Type;
-		readonly List<Sheet> sheets = [];
+		readonly List<Sheet> sheets = new();
 		readonly Func<Sheet> allocateSheet;
 		readonly int margin;
 		int rowHeight = 0;
@@ -65,6 +66,9 @@ namespace OpenRA.Graphics
 			}
 		}
 
+		public SheetBuilder(SheetType t)
+			: this(t, Game.Settings.Graphics.SheetSize) { }
+
 		public SheetBuilder(SheetType t, int sheetSize, int margin = 1)
 			: this(t, () => AllocateSheet(t, sheetSize), margin) { }
 
@@ -72,6 +76,8 @@ namespace OpenRA.Graphics
 		{
 			CurrentChannel = t == SheetType.Indexed ? TextureChannel.Red : TextureChannel.RGBA;
 			Type = t;
+			Current = allocateSheet();
+			sheets.Add(Current);
 			this.allocateSheet = allocateSheet;
 			this.margin = margin;
 		}
@@ -80,12 +86,6 @@ namespace OpenRA.Graphics
 		public Sprite Add(byte[] src, SpriteFrameType type, Size size, bool premultiplied = false) { return Add(src, type, size, 0, float3.Zero, premultiplied); }
 		public Sprite Add(byte[] src, SpriteFrameType type, Size size, float zRamp, in float3 spriteOffset, bool premultiplied = false)
 		{
-			if (Current == null)
-			{
-				Current = allocateSheet();
-				sheets.Add(Current);
-			}
-
 			// Don't bother allocating empty sprites
 			if (size.Width == 0 || size.Height == 0)
 				return new Sprite(Current, Rectangle.Empty, 0, spriteOffset, CurrentChannel, BlendMode.Alpha);
@@ -116,12 +116,6 @@ namespace OpenRA.Graphics
 		public Sprite Allocate(Size imageSize, float scale = 1f) { return Allocate(imageSize, 0, float3.Zero, scale); }
 		public Sprite Allocate(Size imageSize, float zRamp, in float3 spriteOffset, float scale = 1f)
 		{
-			if (Current == null)
-			{
-				Current = allocateSheet();
-				sheets.Add(Current);
-			}
-
 			if (imageSize.Width + p.X + margin > Current.Size.Width)
 			{
 				p = new int2(0, p.Y + rowHeight + margin);

OpenRA.Game/Graphics/SpriteCache.cs

@@ -11,7 +11,6 @@
 
 using System;
 using System.Collections.Generic;
-using System.Collections.Immutable;
 using System.IO;
 using System.Linq;
 using OpenRA.FileSystem;
@@ -28,12 +27,12 @@ namespace OpenRA.Graphics
 
 		readonly Dictionary<
 			int,
-			(ImmutableArray<int> Frames, MiniYamlNode.SourceLocation Location, AdjustFrame AdjustFrame, bool Premultiplied)> spriteReservations = [];
-		readonly Dictionary<string, List<int>> reservationsByFilename = [];
+			(int[] Frames, MiniYamlNode.SourceLocation Location, AdjustFrame AdjustFrame, bool Premultiplied)> spriteReservations = new();
+		readonly Dictionary<string, List<int>> reservationsByFilename = new();
 
-		readonly Dictionary<int, Sprite[]> resolvedSprites = [];
+		readonly Dictionary<int, Sprite[]> resolvedSprites = new();
 
-		readonly Dictionary<int, (string Filename, MiniYamlNode.SourceLocation Location)> missingFiles = [];
+		readonly Dictionary<int, (string Filename, MiniYamlNode.SourceLocation Location)> missingFiles = new();
 
 		int nextReservationToken = 1;
 
@@ -50,12 +49,12 @@ namespace OpenRA.Graphics
 			this.loaders = loaders;
 		}
 
-		public int ReserveSprites(string filename, ImmutableArray<int> frames, MiniYamlNode.SourceLocation location,
+		public int ReserveSprites(string filename, IEnumerable<int> frames, MiniYamlNode.SourceLocation location,
 			AdjustFrame adjustFrame = null, bool premultiplied = false)
 		{
 			var token = nextReservationToken++;
-			spriteReservations[token] = (frames, location, adjustFrame, premultiplied);
-			reservationsByFilename.GetOrAdd(filename, _ => []).Add(token);
+			spriteReservations[token] = (frames?.ToArray(), location, adjustFrame, premultiplied);
+			reservationsByFilename.GetOrAdd(filename, _ => new List<int>()).Add(token);
 			return token;
 		}
 
@@ -104,8 +103,8 @@ namespace OpenRA.Graphics
 								throw new InvalidOperationException($"{rs.Location}: {filename} does not contain frames: " +
 									string.Join(',', rs.Frames.Where(f => f >= loadedFrames.Length)));
 
-							var frames = rs.Frames != null ? rs.Frames : Enumerable.Range(0, loadedFrames.Length);
-							var total = rs.Frames != null ? rs.Frames.Length : loadedFrames.Length;
+							var frames = rs.Frames ?? Enumerable.Range(0, loadedFrames.Length);
+							var total = rs.Frames?.Length ?? loadedFrames.Length;
 
 							var j = 0;
 							foreach (var i in frames)
@@ -156,7 +155,7 @@ namespace OpenRA.Graphics
 			}
 
 			foreach (var sb in SheetBuilders.Values)
-				sb.Current?.ReleaseBuffer();
+				sb.Current.ReleaseBuffer();
 		}
 
 		public Sprite[] ResolveSprites(int token)

OpenRA.Game/Graphics/SpriteRenderable.cs

@@ -9,6 +9,7 @@
  */
 #endregion
 
+using System;
 using System.Collections.Generic;
 using OpenRA.Primitives;
 
@@ -16,7 +17,7 @@ namespace OpenRA.Graphics
 {
 	public class SpriteRenderable : IPalettedRenderable, IModifyableRenderable, IFinalizedRenderable
 	{
-		public static readonly IEnumerable<IRenderable> None = [];
+		public static readonly IEnumerable<IRenderable> None = Array.Empty<IRenderable>();
 
 		readonly Sprite sprite;
 		readonly WPos pos;

OpenRA.Game/Graphics/TerrainSpriteLayer.cs

@@ -19,7 +19,7 @@ namespace OpenRA.Graphics
 	public sealed class TerrainSpriteLayer : IDisposable
 	{
 		// PERF: we can reuse the IndexBuffer as all layers have the same size.
-		static readonly ConditionalWeakTable<World, IndexBufferRc> IndexBuffers = [];
+		static readonly ConditionalWeakTable<World, IndexBufferRc> IndexBuffers = new();
 		readonly IndexBufferRc indexBufferWrapper;
 
 		public readonly BlendMode BlendMode;
@@ -30,7 +30,7 @@ namespace OpenRA.Graphics
 		readonly IVertexBuffer<Vertex> vertexBuffer;
 		readonly Vertex[] vertices;
 		readonly bool[] ignoreTint;
-		readonly HashSet<int> dirtyRows = [];
+		readonly HashSet<int> dirtyRows = new();
 		readonly int indexRowStride;
 		readonly int vertexRowStride;
 		readonly bool restrictToBounds;
@@ -49,23 +49,23 @@ namespace OpenRA.Graphics
 			BlendMode = blendMode;
 			map = world.Map;
 
-			vertexRowStride = 4 * map.MapSize.Width;
-			vertices = new Vertex[vertexRowStride * map.MapSize.Height];
-			vertexBuffer = Game.Renderer.Context.CreateEmptyVertexBuffer<Vertex>(vertices.Length);
+			vertexRowStride = 4 * map.MapSize.X;
+			vertices = new Vertex[vertexRowStride * map.MapSize.Y];
+			vertexBuffer = Game.Renderer.Context.CreateVertexBuffer<Vertex>(vertices.Length);
 
-			indexRowStride = 6 * map.MapSize.Width;
+			indexRowStride = 6 * map.MapSize.X;
 			lock (IndexBuffers)
 			{
 				indexBufferWrapper = IndexBuffers.GetValue(world, world => new IndexBufferRc(world));
 				indexBufferWrapper.AddRef();
 			}
 
-			palettes = new PaletteReference[map.MapSize.Width * map.MapSize.Height];
+			palettes = new PaletteReference[map.MapSize.X * map.MapSize.Y];
 			wr.PaletteInvalidated += UpdatePaletteIndices;
 
 			if (wr.TerrainLighting != null)
 			{
-				ignoreTint = new bool[vertexRowStride * map.MapSize.Height];
+				ignoreTint = new bool[vertexRowStride * map.MapSize.Y];
 				wr.TerrainLighting.CellChanged += UpdateTint;
 			}
 		}
@@ -80,7 +80,7 @@ namespace OpenRA.Graphics
 				vertices[i] = new Vertex(v.X, v.Y, v.Z, v.S, v.T, v.U, v.V, c, v.R, v.G, v.B, v.A);
 			}
 
-			for (var row = 0; row < map.MapSize.Height; row++)
+			for (var row = 0; row < map.MapSize.Y; row++)
 				dirtyRows.Add(row);
 		}
 
@@ -193,7 +193,7 @@ namespace OpenRA.Graphics
 
 			var offset = vertexRowStride * uv.V + 4 * uv.U;
 			Util.FastCreateQuad(vertices, pos, sprite, samplers, palette?.TextureIndex ?? 0, offset, scale * sprite.Size, alpha * float3.Ones, alpha);
-			palettes[uv.V * map.MapSize.Width + uv.U] = palette;
+			palettes[uv.V * map.MapSize.X + uv.U] = palette;
 
 			if (worldRenderer.TerrainLighting != null)
 			{
@@ -209,8 +209,8 @@ namespace OpenRA.Graphics
 			var cells = restrictToBounds ? viewport.VisibleCellsInsideBounds : viewport.AllVisibleCells;
 
 			// Only draw the rows that are visible.
-			var firstRow = cells.CandidateMapCoords.TopLeft.V.Clamp(0, map.MapSize.Height);
-			var lastRow = (cells.CandidateMapCoords.BottomRight.V + 1).Clamp(firstRow, map.MapSize.Height);
+			var firstRow = cells.CandidateMapCoords.TopLeft.V.Clamp(0, map.MapSize.Y);
+			var lastRow = (cells.CandidateMapCoords.BottomRight.V + 1).Clamp(firstRow, map.MapSize.Y);
 
 			Game.Renderer.Flush();
 
@@ -250,8 +250,7 @@ namespace OpenRA.Graphics
 
 			public IndexBufferRc(World world)
 			{
-				Buffer = Game.Renderer.Context.CreateIndexBuffer(
-					Util.CreateQuadIndices(world.Map.MapSize.Width * world.Map.MapSize.Height));
+				Buffer = Game.Renderer.Context.CreateIndexBuffer(Util.CreateQuadIndices(world.Map.MapSize.X * world.Map.MapSize.Y));
 			}
 
 			public void AddRef() { count++; }

OpenRA.Game/Graphics/Util.cs

@@ -19,12 +19,12 @@ namespace OpenRA.Graphics
 	public static class Util
 	{
 		// yes, our channel order is nuts.
-		static readonly int[] ChannelMasks = [2, 1, 0, 3];
+		static readonly int[] ChannelMasks = { 2, 1, 0, 3 };
 
 		public static uint[] CreateQuadIndices(int quads)
 		{
 			var indices = new uint[quads * 6];
-			ReadOnlySpan<uint> cornerVertexMap = [0, 1, 2, 2, 3, 0];
+			ReadOnlySpan<uint> cornerVertexMap = stackalloc uint[] { 0, 1, 2, 2, 3, 0 };
 			for (var i = 0; i < indices.Length; i++)
 				indices[i] = cornerVertexMap[i % 6] + (uint)(4 * (i / 6));
 
@@ -277,13 +277,13 @@ namespace OpenRA.Graphics
 				size.X * angleSin - size.Y * angleCos,
 				(size.X * angleSin - size.Y * angleCos) * size.Z / size.Y);
 
-			return
-			[
+			return new float3[]
+			{
 				center - ra,
 				center + rb,
 				center + ra,
 				center - rb
-			];
+			};
 		}
 
 		/// <summary>

OpenRA.Game/Graphics/Vertex.cs

@@ -53,12 +53,12 @@ namespace OpenRA.Graphics
 			: base("combined")
 		{ }
 
-		public override ShaderVertexAttribute[] Attributes { get; } =
-		[
+		public override ShaderVertexAttribute[] Attributes { get; } = new[]
+		{
 			new ShaderVertexAttribute("aVertexPosition", ShaderVertexAttributeType.Float, 3, 0),
 			new ShaderVertexAttribute("aVertexTexCoord", ShaderVertexAttributeType.Float, 4, 12),
 			new ShaderVertexAttribute("aVertexAttributes", ShaderVertexAttributeType.UInt, 1, 28),
 			new ShaderVertexAttribute("aVertexTint", ShaderVertexAttributeType.Float, 4, 32)
-		];
+		};
 	}
 }

OpenRA.Game/Graphics/Viewport.cs

@@ -11,7 +11,6 @@
 
 using System;
 using System.Collections.Generic;
-using System.Collections.Immutable;
 using System.Linq;
 using OpenRA.Primitives;
 
@@ -50,13 +49,14 @@ namespace OpenRA.Graphics
 		readonly Size tileSize;
 
 		// Viewport geometry (world-px)
-		public float2 CenterLocation { get; private set; }
+		public int2 CenterLocation { get; private set; }
 
-		public WPos CenterPosition => worldRenderer.ProjectedPosition(CenterLocation.ToInt2());
+		public WPos CenterPosition => worldRenderer.ProjectedPosition(CenterLocation);
 
-		public int2 TopLeft => CenterLocation.ToInt2() - ViewportSize.ToInt2() / 2;
-		public int2 BottomRight => CenterLocation.ToInt2() + ViewportSize.ToInt2() / 2;
-		public Size ViewportSize { get; private set; }
+		public Rectangle Rectangle => new(TopLeft, new Size(viewportSize.X, viewportSize.Y));
+		public int2 TopLeft => CenterLocation - viewportSize / 2;
+		public int2 BottomRight => CenterLocation + viewportSize / 2;
+		int2 viewportSize;
 		ProjectedCellRegion cells;
 		bool cellsDirty = true;
 
@@ -69,10 +69,6 @@ namespace OpenRA.Graphics
 		bool unlockMinZoom;
 		float unlockedMinZoomScale;
 		float unlockedMinZoom = 1f;
-		float defaultScale;
-		bool overrideUserScale;
-
-		public Func<float2> ViewportCenterProvider;
 
 		public float Zoom
 		{
@@ -81,7 +77,7 @@ namespace OpenRA.Graphics
 			private set
 			{
 				zoom = value;
-				ViewportSize = Size.FromInt2((1f / zoom * new float2(Game.Renderer.NativeResolution)).ToInt2());
+				viewportSize = (1f / zoom * new float2(Game.Renderer.NativeResolution)).ToInt2();
 				cellsDirty = true;
 				allCellsDirty = true;
 			}
@@ -90,13 +86,6 @@ namespace OpenRA.Graphics
 		public float MinZoom { get; private set; } = 1f;
 		public float MaxZoom { get; private set; } = 2f;
 
-		public void OverrideDefaultHeight(float height)
-		{
-			defaultScale = viewportSizes.DefaultScale * Game.Renderer.NativeResolution.Height / height;
-			overrideUserScale = true;
-			UpdateViewportZooms(false);
-		}
-
 		public void AdjustZoom(float dz)
 		{
 			// Exponential ensures that equal positive and negative steps have the same effect
@@ -108,9 +97,7 @@ namespace OpenRA.Graphics
 			var oldCenter = worldRenderer.Viewport.ViewToWorldPx(center);
 			AdjustZoom(dz);
 			var newCenter = worldRenderer.Viewport.ViewToWorldPx(center);
-
-			var candidateCenterLocation = CenterLocation + oldCenter - newCenter;
-			CenterLocation = candidateCenterLocation.Clamp(mapBounds);
+			CenterLocation += oldCenter - newCenter;
 		}
 
 		public void ToggleZoom()
@@ -150,17 +137,16 @@ namespace OpenRA.Graphics
 		public Viewport(WorldRenderer wr, Map map)
 		{
 			worldRenderer = wr;
-			tileSize = map.Rules.TerrainInfo.TileSize;
-			viewportSizes = Game.ModData.GetOrCreate<WorldViewportSizes>();
+			var grid = Game.ModData.Manifest.Get<MapGrid>();
+			viewportSizes = Game.ModData.Manifest.Get<WorldViewportSizes>();
 			graphicSettings = Game.Settings.Graphics;
-			defaultScale = viewportSizes.DefaultScale;
 
 			// Calculate map bounds in world-px
 			if (wr.World.Type == WorldType.Editor)
 			{
 				// The full map is visible in the editor
-				var width = map.MapSize.Width * tileSize.Width;
-				var height = map.MapSize.Height * tileSize.Height;
+				var width = map.MapSize.X * grid.TileSize.Width;
+				var height = map.MapSize.Y * grid.TileSize.Height;
 				if (wr.World.Map.Grid.Type == MapGridType.RectangularIsometric)
 					height /= 2;
 
@@ -175,6 +161,8 @@ namespace OpenRA.Graphics
 				CenterLocation = (tl + br) / 2;
 			}
 
+			tileSize = grid.TileSize;
+
 			UpdateViewportZooms();
 		}
 
@@ -182,9 +170,6 @@ namespace OpenRA.Graphics
 		{
 			if (lastViewportDistance != graphicSettings.ViewportDistance)
 				UpdateViewportZooms();
-
-			if (ViewportCenterProvider != null)
-				Center(ViewportCenterProvider());
 		}
 
 		static float CalculateMinimumZoom(float minHeight, float maxHeight)
@@ -222,17 +207,17 @@ namespace OpenRA.Graphics
 			lastViewportDistance = graphicSettings.ViewportDistance;
 
 			var vd = graphicSettings.ViewportDistance;
-			if (overrideUserScale || (viewportSizes.AllowNativeZoom && vd == WorldViewport.Native))
-				MinZoom = defaultScale;
+			if (viewportSizes.AllowNativeZoom && vd == WorldViewport.Native)
+				MinZoom = viewportSizes.DefaultScale;
 			else
 			{
 				var range = viewportSizes.GetSizeRange(vd);
-				MinZoom = CalculateMinimumZoom(range.X, range.Y) * defaultScale;
+				MinZoom = CalculateMinimumZoom(range.X, range.Y) * viewportSizes.DefaultScale;
 			}
 
 			MaxZoom = Math.Min(
 				MinZoom * viewportSizes.MaxZoomScale,
-				Game.Renderer.NativeResolution.Height * defaultScale / viewportSizes.MaxZoomWindowHeight);
+				Game.Renderer.NativeResolution.Height * viewportSizes.DefaultScale / viewportSizes.MaxZoomWindowHeight);
 
 			if (unlockMinZoom)
 			{
@@ -258,7 +243,7 @@ namespace OpenRA.Graphics
 
 		public CPos ViewToWorld(int2 view)
 		{
-			var world = ViewToWorldPx(view);
+			var world = worldRenderer.Viewport.ViewToWorldPx(view);
 			var map = worldRenderer.World.Map;
 			var candidates = CandidateMouseoverCells(world).ToList();
 
@@ -271,7 +256,7 @@ namespace OpenRA.Graphics
 				{
 					var ramp = map.Grid.Ramps[map.Ramp.Contains(uv) ? map.Ramp[uv] : 0];
 					var pos = map.CenterOfCell(uv.ToCPos(map)) - new WVec(0, 0, ramp.CenterHeightOffset);
-					var screen = ramp.Corners.Select(c => worldRenderer.ScreenPxPosition(pos + c)).ToImmutableArray();
+					var screen = ramp.Corners.Select(c => worldRenderer.ScreenPxPosition(pos + c)).ToArray();
 					if (screen.PolygonContains(world))
 						return uv.ToCPos(map);
 				}
@@ -323,9 +308,9 @@ namespace OpenRA.Graphics
 					yield return new MPos(u, v);
 		}
 
-		public int2 ViewToWorldPx(int2 view) => (graphicSettings.UIScale / Zoom * view.ToFloat2() + CenterLocation - ViewportSize.ToInt2() / 2).ToInt2();
-		public int2 WorldToViewPx(int2 world) => (Zoom / graphicSettings.UIScale * (world - CenterLocation + ViewportSize.ToInt2() / 2)).ToInt2();
-		public int2 WorldToViewPx(in float3 world) => (Zoom / graphicSettings.UIScale * (world - CenterLocation + ViewportSize.ToInt2() / 2).XY).ToInt2();
+		public int2 ViewToWorldPx(int2 view) { return (graphicSettings.UIScale / Zoom * view.ToFloat2()).ToInt2() + TopLeft; }
+		public int2 WorldToViewPx(int2 world) { return (Zoom / graphicSettings.UIScale * (world - TopLeft).ToFloat2()).ToInt2(); }
+		public int2 WorldToViewPx(in float3 world) { return (Zoom / graphicSettings.UIScale * (world - TopLeft).XY).ToInt2(); }
 
 		public void Center(IEnumerable<Actor> actors)
 		{
@@ -345,17 +330,10 @@ namespace OpenRA.Graphics
 			allCellsDirty = true;
 		}
 
-		public void Center(float2 pos)
-		{
-			CenterLocation = worldRenderer.ScreenPosition(pos).Clamp(mapBounds);
-			cellsDirty = true;
-			allCellsDirty = true;
-		}
-
 		public void Scroll(float2 delta, bool ignoreBorders)
 		{
 			// Convert scroll delta from world-px to viewport-px
-			CenterLocation += 1f / Zoom * delta;
+			CenterLocation += (1f / Zoom * delta).ToInt2();
 			cellsDirty = true;
 			allCellsDirty = true;
 

OpenRA.Game/Graphics/WorldRenderer.cs

@@ -12,7 +12,6 @@
 using System;
 using System.Collections.Generic;
 using System.Linq;
-using System.Runtime.InteropServices;
 using OpenRA.Effects;
 using OpenRA.Primitives;
 using OpenRA.Traits;
@@ -32,33 +31,32 @@ namespace OpenRA.Graphics
 
 		public event Action PaletteInvalidated = null;
 
-		readonly HashSet<Actor> onScreenActors = [];
+		readonly HashSet<Actor> onScreenActors = new();
 		readonly HardwarePalette palette = new();
-		readonly Dictionary<string, PaletteReference> palettes = [];
+		readonly Dictionary<string, PaletteReference> palettes = new();
 		readonly IRenderTerrain terrainRenderer;
 		readonly Lazy<DebugVisualizations> debugVis;
 		readonly Func<string, PaletteReference> createPaletteReference;
 		readonly bool enableDepthBuffer;
 
-		readonly List<IFinalizedRenderable> preparedRenderables = [];
-		readonly List<IFinalizedRenderable> preparedOverlayRenderables = [];
-		readonly List<IFinalizedRenderable> preparedAnnotationRenderables = [];
+		readonly List<IFinalizedRenderable> preparedRenderables = new();
+		readonly List<IFinalizedRenderable> preparedOverlayRenderables = new();
+		readonly List<IFinalizedRenderable> preparedAnnotationRenderables = new();
 
-		readonly List<IRenderable> renderablesBuffer = [];
+		readonly List<IRenderable> renderablesBuffer = new();
 		readonly IRenderer[] renderers;
 		readonly IRenderPostProcessPass[] postProcessPasses;
-		long[] renderablesKeysBuffer = [];
 
 		internal WorldRenderer(ModData modData, World world)
 		{
 			World = world;
-			TileSize = World.Map.Rules.TerrainInfo.TileSize;
+			TileSize = World.Map.Grid.TileSize;
 			TileScale = World.Map.Grid.TileScale;
 			Viewport = new Viewport(this, world.Map);
 
 			createPaletteReference = CreatePaletteReference;
 
-			var mapGrid = modData.GetOrCreate<MapGrid>();
+			var mapGrid = modData.Manifest.Get<MapGrid>();
 			enableDepthBuffer = mapGrid.EnableDepthBuffer;
 
 			foreach (var pal in world.TraitDict.ActorsWithTrait<ILoadsPalettes>())
@@ -72,7 +70,7 @@ namespace OpenRA.Graphics
 			renderers = world.WorldActor.TraitsImplementing<IRenderer>().ToArray();
 			terrainRenderer = world.WorldActor.TraitOrDefault<IRenderTerrain>();
 
-			debugVis = Exts.Lazy(world.WorldActor.TraitOrDefault<DebugVisualizations>);
+			debugVis = Exts.Lazy(() => world.WorldActor.TraitOrDefault<DebugVisualizations>());
 
 			postProcessPasses = world.WorldActor.TraitsImplementing<IRenderPostProcessPass>().ToArray();
 		}
@@ -159,14 +157,7 @@ namespace OpenRA.Graphics
 				renderablesBuffer.AddRange(e.Render(this));
 
 			// Renderables must be ordered using a stable sorting algorithm to avoid flickering artefacts
-			if (renderablesKeysBuffer.Length < renderablesBuffer.Count)
-				renderablesKeysBuffer = new long[Exts.NextPowerOf2(renderablesBuffer.Count)];
-			for (var i = 0; i < renderablesBuffer.Count; i++)
-				renderablesKeysBuffer[i] = ((long)RenderableZPositionComparisonKey(renderablesBuffer[i]) << 32) + i;
-			var keys = renderablesKeysBuffer.AsSpan(0, renderablesBuffer.Count);
-			keys.Sort(CollectionsMarshal.AsSpan(renderablesBuffer));
-
-			foreach (var renderable in renderablesBuffer)
+			foreach (var renderable in renderablesBuffer.OrderBy(RenderableZPositionComparisonKey))
 				preparedRenderables.Add(renderable.PrepareRender(this));
 
 			// PERF: Reuse collection to avoid allocations.
@@ -380,8 +371,6 @@ namespace OpenRA.Graphics
 				}
 			}
 
-			ApplyPostProcessing(PostProcessPassType.AfterAnnotations);
-
 			Game.Renderer.Flush();
 
 			preparedRenderables.Clear();
@@ -395,22 +384,12 @@ namespace OpenRA.Graphics
 			Game.Renderer.SetPalette(palette);
 		}
 
-		/// <summary>
-		/// Converts a world position to a screen position.
-		/// </summary>
+		// Conversion between world and screen coordinates
 		public float2 ScreenPosition(WPos pos)
 		{
 			return new float2((float)TileSize.Width * pos.X / TileScale, (float)TileSize.Height * (pos.Y - pos.Z) / TileScale);
 		}
 
-		/// <summary>
-		/// Converts a world position to a screen position.
-		/// </summary>
-		public float2 ScreenPosition(float2 pos)
-		{
-			return new float2(TileSize.Width * pos.X / TileScale, TileSize.Height * pos.Y / TileScale);
-		}
-
 		public float3 Screen3DPosition(WPos pos)
 		{
 			// The projection from world coordinates to screen coordinates has
@@ -450,7 +429,7 @@ namespace OpenRA.Graphics
 		public float[] ScreenVector(in WVec vec)
 		{
 			var xyz = ScreenVectorComponents(vec);
-			return [xyz.X, xyz.Y, xyz.Z, 1f];
+			return new[] { xyz.X, xyz.Y, xyz.Z, 1f };
 		}
 
 		public int2 ScreenPxOffset(in WVec vec)

OpenRA.Game/HotkeyDefinition.cs

@@ -9,8 +9,7 @@
  */
 #endregion
 
-using System.Collections.Frozen;
-using System.Collections.Immutable;
+using System.Collections.Generic;
 using System.Linq;
 
 namespace OpenRA
@@ -25,10 +24,10 @@ namespace OpenRA
 		[FluentReference]
 		public readonly string Description = "";
 
-		public readonly FrozenSet<string> Types = FrozenSet<string>.Empty;
+		public readonly HashSet<string> Types = new();
 
 		[FluentReference]
-		public readonly FrozenSet<string> Contexts = FrozenSet<string>.Empty;
+		public readonly HashSet<string> Contexts = new();
 
 		public readonly bool Readonly = false;
 		public bool HasDuplicates { get; internal set; }
@@ -46,11 +45,11 @@ namespace OpenRA
 				Description = descriptionYaml.Value;
 
 			if (nodeDict.TryGetValue("Types", out var typesYaml))
-				Types = FieldLoader.GetValue<FrozenSet<string>>("Types", typesYaml.Value);
+				Types = FieldLoader.GetValue<HashSet<string>>("Types", typesYaml.Value);
 
 			if (nodeDict.TryGetValue("Contexts", out var contextYaml))
-				Contexts = FieldLoader.GetValue<ImmutableArray<string>>("Contexts", contextYaml.Value)
-					.Select(c => ContextFluentPrefix + "." + c).ToFrozenSet();
+				Contexts = FieldLoader.GetValue<HashSet<string>>("Contexts", contextYaml.Value)
+					.Select(c => ContextFluentPrefix + "." + c).ToHashSet();
 
 			if (nodeDict.TryGetValue("Platform", out var platformYaml))
 			{

OpenRA.Game/HotkeyManager.cs

@@ -17,16 +17,13 @@ namespace OpenRA
 {
 	public sealed class HotkeyManager
 	{
-		[YamlNode("Keys", shared: true)]
-		sealed class HotkeySettings : SettingsModule { }
+		readonly Dictionary<string, Hotkey> settings;
+		readonly Dictionary<string, HotkeyDefinition> definitions = new();
+		readonly Dictionary<string, Hotkey> keys = new();
 
-		readonly Dictionary<string, HotkeyDefinition> definitions = [];
-		readonly Dictionary<string, Hotkey> keys = [];
-		readonly HotkeySettings hotkeySettings;
-
-		public HotkeyManager(IReadOnlyFileSystem fileSystem, ObjectCreator objectCreator, Manifest manifest)
+		public HotkeyManager(IReadOnlyFileSystem fileSystem, Dictionary<string, Hotkey> settings, Manifest manifest)
 		{
-			hotkeySettings = Game.Settings.GetOrCreate<HotkeySettings>(objectCreator, manifest.Id);
+			this.settings = settings;
 
 			var keyDefinitions = MiniYaml.Load(fileSystem, manifest.Hotkeys, null);
 			foreach (var kd in keyDefinitions)
@@ -36,9 +33,11 @@ namespace OpenRA
 				keys[kd.Key] = definition.Default;
 			}
 
-			foreach (var node in hotkeySettings.Yaml.Nodes)
-				if (definitions.TryGetValue(node.Key, out var definition) && !definition.Readonly)
-					keys[node.Key] = FieldLoader.GetValue<Hotkey>(node.Key, node.Value.Value);
+			foreach (var kv in settings)
+			{
+				if (definitions.TryGetValue(kv.Key, out var definition) && !definition.Readonly)
+					keys[kv.Key] = kv.Value;
+			}
 
 			foreach (var hd in definitions)
 				hd.Value.HasDuplicates = GetFirstDuplicate(hd.Value, this[hd.Value.Name].GetValue()) != null;
@@ -69,9 +68,10 @@ namespace OpenRA
 				return;
 
 			keys[name] = value;
-			hotkeySettings.Yaml.Nodes.RemoveAll(n => n.Key == name);
 			if (value != definition.Default)
-				hotkeySettings.Yaml.Nodes.Add(new MiniYamlNodeBuilder(name, FieldSaver.FormatValue(value)));
+				settings[name] = value;
+			else
+				settings.Remove(name);
 
 			var hadDuplicates = definition.HasDuplicates;
 			definition.HasDuplicates = GetFirstDuplicate(definition, this[definition.Name].GetValue()) != null;
@@ -108,10 +108,5 @@ namespace OpenRA
 		public HotkeyReference this[string name] => new(GetHotkeyReference(name));
 
 		public IEnumerable<HotkeyDefinition> Definitions => definitions.Values;
-
-		public void Save()
-		{
-			hotkeySettings.Save();
-		}
 	}
 }

OpenRA.Game/HttpExtension.cs

@@ -26,7 +26,11 @@ namespace OpenRA
 			var total = response.Content.Headers.ContentLength ?? -1;
 			var canReportProgress = total > 0;
 
-			await using (var contentStream = await response.Content.ReadAsStreamAsync(token))
+#if NET5_0_OR_GREATER
+			using (var contentStream = await response.Content.ReadAsStreamAsync(token))
+#else
+			using (var contentStream = await response.Content.ReadAsStreamAsync())
+#endif
 			{
 				var totalRead = 0L;
 				var buffer = new byte[8192];

OpenRA.Game/Input/Hotkey.cs

@@ -27,21 +27,25 @@ namespace OpenRA
 		public static bool TryParse(string s, out Hotkey result)
 		{
 			result = Invalid;
-			if (s == null)
+			if (string.IsNullOrWhiteSpace(s))
 				return false;
 
-			Span<Range> ranges = stackalloc Range[2];
-			var span = s.AsSpan();
-			var count = span.Split(ranges, ' ');
-			if (count == 0)
-				return false;
+			var parts = s.Split(' ');
 
-			if (!Enum.TryParse(span[ranges[0]], true, out Keycode key))
+			if (!Enum<Keycode>.TryParse(parts[0], true, out var key))
+			{
+				if (!int.TryParse(parts[0], out var c))
 					return false;
+				key = (Keycode)c;
+			}
 
 			var mods = Modifiers.None;
-			if (count == 2 && !Enum.TryParse(span[ranges[1]], true, out mods))
+			if (parts.Length >= 2)
+			{
+				var modString = s[s.IndexOf(' ')..];
+				if (!Enum<Modifiers>.TryParse(modString, true, out mods))
 					return false;
+			}
 
 			result = new Hotkey(key, mods);
 			return true;

OpenRA.Game/Input/IInputHandler.cs

@@ -23,7 +23,25 @@ namespace OpenRA
 	}
 
 	public enum MouseInputEvent { Down, Move, Up, Scroll }
-	public record struct MouseInput(MouseInputEvent Event, MouseButton Button, int2 Location, int2 Delta, Modifiers Modifiers, int MultiTapCount);
+	public struct MouseInput
+	{
+		public MouseInputEvent Event;
+		public MouseButton Button;
+		public int2 Location;
+		public int2 Delta;
+		public Modifiers Modifiers;
+		public int MultiTapCount;
+
+		public MouseInput(MouseInputEvent ev, MouseButton button, int2 location, int2 delta, Modifiers mods, int multiTapCount)
+		{
+			Event = ev;
+			Button = button;
+			Location = location;
+			Delta = delta;
+			Modifiers = mods;
+			MultiTapCount = multiTapCount;
+		}
+	}
 
 	[Flags]
 	public enum MouseButton
@@ -47,7 +65,7 @@ namespace OpenRA
 	public static class ModifiersExts
 	{
 		[FluentReference]
-		const string Cmd = "keycode-modifier.cmd";
+		public const string Cmd = "keycode-modifier.cmd";
 
 		[FluentReference(Traits.LintDictionaryReference.Values)]
 		public static readonly IReadOnlyDictionary<Modifiers, string> ModifierFluentKeys = new Dictionary<Modifiers, string>()

OpenRA.Game/Input/InputHandler.cs

@@ -50,4 +50,11 @@ namespace OpenRA
 			Sync.RunUnsynced(world, () => Ui.HandleInput(input));
 		}
 	}
+
+	public class MouseButtonPreference
+	{
+		public MouseButton Action => Game.Settings.Game.UseClassicMouseStyle ? MouseButton.Left : MouseButton.Right;
+
+		public MouseButton Cancel => Game.Settings.Game.UseClassicMouseStyle ? MouseButton.Right : MouseButton.Left;
+	}
 }

OpenRA.Game/MPos.cs

@@ -56,7 +56,8 @@ namespace OpenRA
 			// (b) Therefore:
 			//  - au + 2bv adds (a + b) to (x, y)
 			//  - a correction factor is added if v is odd
-			var y = (V - (V & 1)) / 2 - U;
+			var offset = (V & 1) == 1 ? 1 : 0;
+			var y = (V - offset) / 2 - U;
 			var x = V - y;
 			return new CPos(x, y);
 		}

OpenRA.Game/Manifest.cs

@@ -9,27 +9,51 @@
  */
 #endregion
 
-using System.Collections.Frozen;
+using System;
 using System.Collections.Generic;
-using System.Collections.Immutable;
+using System.Collections.ObjectModel;
 using System.IO;
 using System.Linq;
 using OpenRA.FileSystem;
+using OpenRA.Primitives;
 
 namespace OpenRA
 {
+	public interface IGlobalModData { }
+
+	public sealed class TerrainFormat : IGlobalModData
+	{
+		public readonly string Type;
+		public readonly IReadOnlyDictionary<string, MiniYaml> Metadata;
+		public TerrainFormat(MiniYaml yaml)
+		{
+			Type = yaml.Value;
+			Metadata = new ReadOnlyDictionary<string, MiniYaml>(yaml.ToDictionary());
+		}
+	}
+
+	public sealed class SpriteSequenceFormat : IGlobalModData
+	{
+		public readonly string Type;
+		public readonly IReadOnlyDictionary<string, MiniYaml> Metadata;
+		public SpriteSequenceFormat(MiniYaml yaml)
+		{
+			Type = yaml.Value;
+			Metadata = new ReadOnlyDictionary<string, MiniYaml>(yaml.ToDictionary());
+		}
+	}
+
 	public class ModMetadata
 	{
 		// FieldLoader used here, must matching naming in YAML.
 #pragma warning disable IDE1006 // Naming Styles
 		[FluentReference]
-		public readonly string Title;
+		readonly string Title;
 		public readonly string Version;
 		public readonly string Website;
 		public readonly string WebIcon32;
-
-		[FluentReference(optional: true)]
-		public readonly string WindowTitle;
+		[FluentReference]
+		readonly string WindowTitle;
 		public readonly bool Hidden;
 #pragma warning restore IDE1006 // Naming Styles
 
@@ -37,56 +61,48 @@ namespace OpenRA
 		public string WindowTitleTranslated => WindowTitle != null ? FluentProvider.GetMessage(WindowTitle) : null;
 	}
 
-	public class RendererConstants
-	{
-		public readonly int FontSheetSize = 512;
-		public readonly int CursorSheetSize = 512;
-		public readonly int MapPreviewSheetSize = 2048;
-		public readonly int SequenceBgraSheetSize = 2048;
-		public readonly int SequenceIndexedSheetSize = 2048;
-		public readonly int VertexBatchSize = 8192;
-	}
-
 	/// <summary>Describes what is to be loaded in order to run a mod.</summary>
-	public sealed class Manifest
+	public sealed class Manifest : IDisposable
 	{
 		public readonly string Id;
 		public readonly IReadOnlyPackage Package;
 		public readonly ModMetadata Metadata;
-		public readonly ImmutableArray<string>
+		public readonly string[]
 			Rules, ServerTraits,
 			Sequences, ModelSequences, Cursors, Chrome, ChromeLayout,
 			Weapons, Voices, Notifications, Music, FluentMessages, TileSets,
 			ChromeMetrics, MapCompatibility, Missions, Hotkeys;
 
-		public readonly FrozenDictionary<string, string> MapFolders;
+		public readonly IReadOnlyDictionary<string, string> MapFolders;
 		public readonly MiniYaml FileSystem;
 		public readonly MiniYaml LoadScreen;
 		public readonly string DefaultOrderGenerator;
-		public readonly RendererConstants RendererConstants;
 
-		public readonly ImmutableArray<string> Assemblies = [];
-		public readonly ImmutableArray<string> SoundFormats = [];
-		public readonly ImmutableArray<string> SpriteFormats = [];
-		public readonly ImmutableArray<string> PackageFormats = [];
-		public readonly ImmutableArray<string> VideoFormats = [];
-		public readonly string SpriteSequenceFormat;
-		public readonly string TerrainFormat;
+		public readonly string[] Assemblies = Array.Empty<string>();
+		public readonly string[] SoundFormats = Array.Empty<string>();
+		public readonly string[] SpriteFormats = Array.Empty<string>();
+		public readonly string[] PackageFormats = Array.Empty<string>();
+		public readonly string[] VideoFormats = Array.Empty<string>();
+		public readonly int FontSheetSize = 512;
+		public readonly int CursorSheetSize = 512;
 
 		// TODO: This should be controlled by a user-selected translation bundle!
 		public readonly string FluentCulture = "en";
 		public readonly bool AllowUnusedFluentMessagesInExternalPackages = true;
 
-		static readonly FrozenSet<string> ReservedModuleNames = new HashSet<string>
+		readonly string[] reservedModuleNames =
 		{
 			"Include", "Metadata", "FileSystem", "MapFolders", "Rules",
 			"Sequences", "ModelSequences", "Cursors", "Chrome", "Assemblies", "ChromeLayout", "Weapons",
 			"Voices", "Notifications", "Music", "FluentMessages", "TileSets", "ChromeMetrics", "Missions", "Hotkeys",
 			"ServerTraits", "LoadScreen", "DefaultOrderGenerator", "SupportsMapsFrom", "SoundFormats", "SpriteFormats", "VideoFormats",
-			"SpriteSequenceFormat", "TerrainFormat", "RequiresMods", "PackageFormats", "AllowUnusedFluentMessagesInExternalPackages", "RendererConstants"
-		}.ToFrozenSet();
+			"RequiresMods", "PackageFormats", "AllowUnusedFluentMessagesInExternalPackages", "FontSheetSize", "CursorSheetSize"
+		};
 
-		public readonly FrozenDictionary<string, MiniYaml> GlobalModData;
+		readonly TypeDictionary modules = new();
+		readonly Dictionary<string, MiniYaml> yaml;
+
+		bool customDataLoaded;
 
 		public Manifest(string modId, IReadOnlyPackage package)
 		{
@@ -94,7 +110,7 @@ namespace OpenRA
 			Package = package;
 
 			var stringPool = new HashSet<string>(); // Reuse common strings in YAML
-			var nodes = MiniYaml.FromStream(package.GetStream("mod.yaml"), $"{package.Name}:mod.yaml", stringPool: stringPool).ToList();
+			var nodes = MiniYaml.FromStream(package.GetStream("mod.yaml"), $"{package.Name}:mod.yaml", stringPool: stringPool);
 			for (var i = nodes.Count - 1; i >= 0; i--)
 			{
 				if (nodes[i].Key != "Include")
@@ -111,7 +127,7 @@ namespace OpenRA
 			}
 
 			// Merge inherited overrides
-			var yaml = new MiniYaml(null, MiniYaml.Merge([nodes])).ToDictionary();
+			yaml = new MiniYaml(null, MiniYaml.Merge(new[] { nodes })).ToDictionary();
 
 			Metadata = FieldLoader.Load<ModMetadata>(yaml["Metadata"]);
 
@@ -148,59 +164,144 @@ namespace OpenRA
 			if (yaml.TryGetValue("SupportsMapsFrom", out var entry))
 				compat.AddRange(entry.Value.Split(',').Select(c => c.Trim()));
 
-			MapCompatibility = compat.ToImmutableArray();
+			MapCompatibility = compat.ToArray();
 
 			if (yaml.TryGetValue("DefaultOrderGenerator", out entry))
 				DefaultOrderGenerator = entry.Value;
 
 			if (yaml.TryGetValue("Assemblies", out entry))
-				Assemblies = FieldLoader.GetValue<ImmutableArray<string>>("Assemblies", entry.Value);
+				Assemblies = FieldLoader.GetValue<string[]>("Assemblies", entry.Value);
 
 			if (yaml.TryGetValue("PackageFormats", out entry))
-				PackageFormats = FieldLoader.GetValue<ImmutableArray<string>>("PackageFormats", entry.Value);
+				PackageFormats = FieldLoader.GetValue<string[]>("PackageFormats", entry.Value);
 
 			if (yaml.TryGetValue("SoundFormats", out entry))
-				SoundFormats = FieldLoader.GetValue<ImmutableArray<string>>("SoundFormats", entry.Value);
+				SoundFormats = FieldLoader.GetValue<string[]>("SoundFormats", entry.Value);
 
 			if (yaml.TryGetValue("SpriteFormats", out entry))
-				SpriteFormats = FieldLoader.GetValue<ImmutableArray<string>>("SpriteFormats", entry.Value);
+				SpriteFormats = FieldLoader.GetValue<string[]>("SpriteFormats", entry.Value);
 
 			if (yaml.TryGetValue("VideoFormats", out entry))
-				VideoFormats = FieldLoader.GetValue<ImmutableArray<string>>("VideoFormats", entry.Value);
-
-			if (yaml.TryGetValue("SpriteSequenceFormat", out entry))
-				SpriteSequenceFormat = entry.Value;
-
-			if (yaml.TryGetValue("TerrainFormat", out entry))
-				TerrainFormat = entry.Value;
+				VideoFormats = FieldLoader.GetValue<string[]>("VideoFormats", entry.Value);
 
 			if (yaml.TryGetValue("AllowUnusedFluentMessagesInExternalPackages", out entry))
 				AllowUnusedFluentMessagesInExternalPackages =
 					FieldLoader.GetValue<bool>("AllowUnusedFluentMessagesInExternalPackages", entry.Value);
 
-			if (yaml.TryGetValue("RendererConstants", out entry))
-				RendererConstants = FieldLoader.Load<RendererConstants>(entry);
+			if (yaml.TryGetValue("FontSheetSize", out entry))
+				FontSheetSize = FieldLoader.GetValue<int>("FontSheetSize", entry.Value);
+
+			if (yaml.TryGetValue("CursorSheetSize", out entry))
+				CursorSheetSize = FieldLoader.GetValue<int>("CursorSheetSize", entry.Value);
+		}
+
+		public void LoadCustomData(ObjectCreator oc)
+		{
+			foreach (var kv in yaml)
+			{
+				if (reservedModuleNames.Contains(kv.Key))
+					continue;
+
+				var t = oc.FindType(kv.Key);
+				if (t == null || !typeof(IGlobalModData).IsAssignableFrom(t))
+					throw new InvalidDataException($"`{kv.Key}` is not a valid mod manifest entry.");
+
+				IGlobalModData module;
+				var ctor = t.GetConstructor(new[] { typeof(MiniYaml) });
+				if (ctor != null)
+				{
+					// Class has opted-in to DIY initialization
+					module = (IGlobalModData)ctor.Invoke(new object[] { kv.Value });
+				}
 				else
-				RendererConstants = new RendererConstants();
-
-			GlobalModData = yaml.Where(n => !ReservedModuleNames.Contains(n.Key))
-				.ToFrozenDictionary(n => n.Key, n => n.Value);
+				{
+					// Automatically load the child nodes using FieldLoader
+					module = oc.CreateObject<IGlobalModData>(kv.Key);
+					FieldLoader.Load(module, kv.Value);
 				}
 
-		static ImmutableArray<string> YamlList(Dictionary<string, MiniYaml> yaml, string key)
+				modules.Add(module);
+			}
+
+			customDataLoaded = true;
+		}
+
+		static string[] YamlList(Dictionary<string, MiniYaml> yaml, string key)
 		{
 			if (!yaml.TryGetValue(key, out var value))
-				return [];
+				return Array.Empty<string>();
 
-			return value.Nodes.Select(n => n.Key).ToImmutableArray();
+			return value.Nodes.Select(n => n.Key).ToArray();
 		}
 
-		static FrozenDictionary<string, string> YamlDictionary(Dictionary<string, MiniYaml> yaml, string key)
+		static IReadOnlyDictionary<string, string> YamlDictionary(Dictionary<string, MiniYaml> yaml, string key)
 		{
 			if (!yaml.TryGetValue(key, out var value))
-				return FrozenDictionary<string, string>.Empty;
+				return new Dictionary<string, string>();
 
-			return value.ToDictionary(my => my.Value).ToFrozenDictionary();
+			return value.ToDictionary(my => my.Value);
+		}
+
+		public bool Contains<T>() where T : IGlobalModData
+		{
+			return modules.Contains<T>();
+		}
+
+		/// <summary>Load a cached IGlobalModData instance.</summary>
+		public T Get<T>() where T : IGlobalModData
+		{
+			if (!customDataLoaded)
+				throw new InvalidOperationException("Attempted to call Manifest.Get() before loading custom data!");
+
+			var module = modules.GetOrDefault<T>();
+
+			// Lazily create the default values if not explicitly defined.
+			if (module == null)
+			{
+				module = (T)Game.ModData.ObjectCreator.CreateBasic(typeof(T));
+				modules.Add(module);
+			}
+
+			return module;
+		}
+
+		/// <summary>
+		/// Load an uncached IGlobalModData instance directly from the manifest yaml.
+		/// This should only be used by external mods that want to query data from this mod.
+		/// </summary>
+		public T Get<T>(ObjectCreator oc) where T : IGlobalModData
+		{
+			var t = typeof(T);
+			if (!yaml.TryGetValue(t.Name, out var data))
+			{
+				// Lazily create the default values if not explicitly defined.
+				return (T)oc.CreateBasic(t);
+			}
+
+			IGlobalModData module;
+			var ctor = t.GetConstructor(new[] { typeof(MiniYaml) });
+			if (ctor != null)
+			{
+				// Class has opted-in to DIY initialization
+				module = (IGlobalModData)ctor.Invoke(new object[] { data.Value });
+			}
+			else
+			{
+				// Automatically load the child nodes using FieldLoader
+				module = oc.CreateObject<IGlobalModData>(t.Name);
+				FieldLoader.Load(module, data);
+			}
+
+			return (T)module;
+		}
+
+		public void Dispose()
+		{
+			foreach (var module in modules)
+			{
+				var disposableModule = module as IDisposable;
+				disposableModule?.Dispose();
+			}
 		}
 	}
 }

OpenRA.Game/Map/ActorInitializer.cs

@@ -216,8 +216,10 @@ namespace OpenRA
 		}
 	}
 
-	public class LocationInit(CPos value) : ValueActorInit<CPos>(value), ISingleInstanceInit
+	public class LocationInit : ValueActorInit<CPos>, ISingleInstanceInit
 	{
+		public LocationInit(CPos value)
+			: base(value) { }
 	}
 
 	public class OwnerInit : ActorInit, ISingleInstanceInit

OpenRA.Game/Map/ActorReference.cs

@@ -14,7 +14,7 @@ using System.Collections;
 using System.Collections.Generic;
 using System.IO;
 using System.Linq;
-using System.Runtime.CompilerServices;
+using System.Runtime.Serialization;
 using OpenRA.Primitives;
 using OpenRA.Traits;
 
@@ -30,15 +30,15 @@ namespace OpenRA
 		internal TypeDictionary InitDict => initDict.Value;
 
 		public ActorReference(string type)
-			: this(type, new MiniYaml("")) { }
+			: this(type, new Dictionary<string, MiniYaml>()) { }
 
-		public ActorReference(string type, MiniYaml inits)
+		public ActorReference(string type, Dictionary<string, MiniYaml> inits)
 		{
 			Type = type;
 			initDict = Exts.Lazy(() =>
 			{
 				var dict = new TypeDictionary();
-				foreach (var i in inits.Nodes)
+				foreach (var i in inits)
 				{
 					var init = LoadInit(i.Key, i.Value);
 					if (init is ISingleInstanceInit && dict.Contains(init.GetType()))
@@ -54,8 +54,13 @@ namespace OpenRA
 		public ActorReference(string type, TypeDictionary inits)
 		{
 			Type = type;
-			var initsClone = new TypeDictionary(inits);
-			initDict = Exts.Lazy(() => initsClone);
+			initDict = new Lazy<TypeDictionary>(() =>
+			{
+				var dict = new TypeDictionary();
+				foreach (var i in inits)
+					dict.Add(i);
+				return dict;
+			});
 		}
 
 		static ActorInit LoadInit(string initName, MiniYaml initYaml)
@@ -65,15 +70,15 @@ namespace OpenRA
 			if (type == null)
 				throw new InvalidDataException($"Unknown initializer type '{initInstance[0]}Init'");
 
-			var init = (ActorInit)RuntimeHelpers.GetUninitializedObject(type);
+			var init = (ActorInit)FormatterServices.GetUninitializedObject(type);
 			if (initInstance.Length > 1)
 				type.GetField(nameof(ActorInit.InstanceName)).SetValue(init, initInstance[1]);
 
-			var loader = type.GetMethod("Initialize", [typeof(MiniYaml)]);
+			var loader = type.GetMethod("Initialize", new[] { typeof(MiniYaml) });
 			if (loader == null)
 				throw new InvalidDataException($"{initInstance[0]}Init does not define a yaml-assignable type.");
 
-			loader.Invoke(init, [initYaml]);
+			loader.Invoke(init, new[] { initYaml });
 			return init;
 		}
 
@@ -105,7 +110,11 @@ namespace OpenRA
 
 		public ActorReference Clone()
 		{
-			return new ActorReference(Type, initDict.Value);
+			var clone = new ActorReference(Type);
+			foreach (var init in initDict.Value)
+				clone.initDict.Value.Add(init);
+
+			return clone;
 		}
 
 		public void Add(ActorInit init)
@@ -116,15 +125,6 @@ namespace OpenRA
 			InitDict.Add(init);
 		}
 
-		public void Replace<T>(T init) where T : ActorInit, ISingleInstanceInit
-		{
-			var original = GetOrDefault<T>();
-			if (original != null)
-				Remove(original);
-
-			Add(init);
-		}
-
 		public void Remove(ActorInit o) { initDict.Value.Remove(o); }
 
 		public int RemoveAll<T>() where T : ActorInit

OpenRA.Game/Map/CellCoordsRegion.cs

@@ -9,7 +9,6 @@
  */
 #endregion
 
-using System;
 using System.Collections;
 using System.Collections.Generic;
 
@@ -90,31 +89,6 @@ namespace OpenRA
 			return GetEnumerator();
 		}
 
-		/// <summary>Returns the minimal region that covers at least the specified cells.</summary>
-		public static CellCoordsRegion BoundingRegion(IReadOnlyCollection<CPos> cells)
-		{
-			if (cells == null || cells.Count == 0)
-				throw new ArgumentException("cells must not be null or empty.", nameof(cells));
-
-			var minX = int.MaxValue;
-			var minY = int.MaxValue;
-			var maxX = int.MinValue;
-			var maxY = int.MinValue;
-			foreach (var cell in cells)
-			{
-				if (minX > cell.X)
-					minX = cell.X;
-				if (maxX < cell.X)
-					maxX = cell.X;
-				if (minY > cell.Y)
-					minY = cell.Y;
-				if (maxY < cell.Y)
-					maxY = cell.Y;
-			}
-
-			return new CellCoordsRegion(new CPos(minX, minY), new CPos(maxX, maxY));
-		}
-
 		public CPos TopLeft { get; }
 		public CPos BottomRight { get; }
 	}

OpenRA.Game/Map/CellLayer.cs

@@ -63,16 +63,12 @@ namespace OpenRA
 
 			var u = (x - y) / 2;
 			var v = x + y;
-			if (!Bounds.Contains(u, v))
-				throw new IndexOutOfRangeException();
 			return v * Size.Width + u;
 		}
 
 		// Resolve an array index from map coordinates
 		int Index(MPos uv)
 		{
-			if (!Bounds.Contains(uv.U, uv.V))
-				throw new IndexOutOfRangeException();
 			return uv.V * Size.Width + uv.U;
 		}
 
@@ -149,9 +145,6 @@ namespace OpenRA
 		{
 			return uv.Clamp(new Rectangle(0, 0, Size.Width - 1, Size.Height - 1));
 		}
-
-		public CellRegion CellRegion =>
-			new(GridType, new MPos(0, 0), new MPos(Size.Width - 1, Size.Height - 1));
 	}
 
 	// Helper functions

OpenRA.Game/Map/CellLayerBase.cs

@@ -25,7 +25,7 @@ namespace OpenRA
 		protected readonly Rectangle Bounds;
 
 		protected CellLayerBase(Map map)
-			: this(map.Grid.Type, map.MapSize) { }
+			: this(map.Grid.Type, new Size(map.MapSize.X, map.MapSize.Y)) { }
 
 		protected CellLayerBase(MapGridType gridType, Size size)
 		{
@@ -40,19 +40,19 @@ namespace OpenRA
 			if (Size != anotherLayer.Size || GridType != anotherLayer.GridType)
 				throw new ArgumentException("Layers must have a matching size and shape (grid type).", nameof(anotherLayer));
 
-			anotherLayer.Entries.AsSpan().CopyTo(Entries);
+			Array.Copy(anotherLayer.Entries, Entries, Entries.Length);
 		}
 
 		/// <summary>Clears the layer contents with their default value.</summary>
 		public virtual void Clear()
 		{
-			Entries.AsSpan().Clear();
+			Array.Clear(Entries, 0, Entries.Length);
 		}
 
 		/// <summary>Clears the layer contents with a known value.</summary>
 		public virtual void Clear(T clearValue)
 		{
-			Entries.AsSpan().Fill(clearValue);
+			Array.Fill(Entries, clearValue);
 		}
 
 		public IEnumerator<T> GetEnumerator()
@@ -64,15 +64,5 @@ namespace OpenRA
 		{
 			return GetEnumerator();
 		}
-
-		public ReadOnlyMemory<T> AsReadOnlyMemory()
-		{
-			return Entries.AsMemory();
-		}
-
-		public Memory<T> AsMemory()
-		{
-			return Entries.AsMemory();
-		}
 	}
 }

OpenRA.Game/Map/Map.cs

@@ -33,12 +33,12 @@ namespace OpenRA
 		public readonly uint HeightsOffset;
 		public readonly uint ResourcesOffset;
 
-		public BinaryDataHeader(Stream s, Size expectedSize)
+		public BinaryDataHeader(Stream s, int2 expectedSize)
 		{
 			Format = s.ReadUInt8();
 			var width = s.ReadUInt16();
 			var height = s.ReadUInt16();
-			if (width != expectedSize.Width || height != expectedSize.Height)
+			if (width != expectedSize.X || height != expectedSize.Y)
 				throw new InvalidDataException("Invalid tile data");
 
 			if (Format == 1)
@@ -112,7 +112,7 @@ namespace OpenRA
 				else if (type == Type.MiniYaml)
 					field.SetValue(map, node.Value);
 				else
-					FieldLoader.LoadFieldOrProperty(map, fieldName, node.Value.Value);
+					FieldLoader.LoadField(map, fieldName, node.Value.Value);
 			}
 
 			if (property != null)
@@ -122,7 +122,7 @@ namespace OpenRA
 				else if (type == Type.MiniYaml)
 					property.SetValue(map, node.Value, null);
 				else
-					FieldLoader.LoadFieldOrProperty(map, fieldName, node.Value.Value);
+					FieldLoader.LoadField(map, fieldName, node.Value.Value);
 			}
 		}
 
@@ -158,7 +158,7 @@ namespace OpenRA
 
 		/// <summary>Defines the order of the fields in map.yaml.</summary>
 		static readonly MapField[] YamlFields =
-		[
+		{
 			new("MapFormat"),
 			new("RequiresMod"),
 			new("Title"),
@@ -179,7 +179,7 @@ namespace OpenRA
 			new("Voices", nameof(VoiceDefinitions), required: false),
 			new("Music", nameof(MusicDefinitions), required: false),
 			new("Notifications", nameof(NotificationDefinitions), required: false),
-		];
+		};
 
 		// Format versions
 		public int MapFormat { get; private set; }
@@ -193,13 +193,13 @@ namespace OpenRA
 		public bool LockPreview;
 		public Rectangle Bounds;
 		public MapVisibility Visibility = MapVisibility.Lobby;
-		public ImmutableArray<string> Categories = ["Conquest"];
+		public string[] Categories = { "Conquest" };
 
-		public Size MapSize { get; private set; }
+		public int2 MapSize { get; private set; }
 
 		// Player and actor yaml. Public for access by the map importers and lint checks.
-		public IReadOnlyCollection<MiniYamlNode> PlayerDefinitions = [];
-		public IReadOnlyCollection<MiniYamlNode> ActorDefinitions = [];
+		public IReadOnlyCollection<MiniYamlNode> PlayerDefinitions = ImmutableArray<MiniYamlNode>.Empty;
+		public IReadOnlyCollection<MiniYamlNode> ActorDefinitions = ImmutableArray<MiniYamlNode>.Empty;
 
 		// Custom map yaml. Public for access by the map importers and lint checks
 		public MiniYaml RuleDefinitions;
@@ -211,7 +211,7 @@ namespace OpenRA
 		public MiniYaml MusicDefinitions;
 		public MiniYaml NotificationDefinitions;
 
-		public readonly Dictionary<CPos, TerrainTile> ReplacedInvalidTerrainTiles = [];
+		public readonly Dictionary<CPos, TerrainTile> ReplacedInvalidTerrainTiles = new();
 
 		// Generated data
 		public readonly MapGrid Grid;
@@ -283,7 +283,7 @@ namespace OpenRA
 
 				// Take the SHA1
 				if (streams.Count == 0)
-					return CryptoUtil.SHA1Hash([]);
+					return CryptoUtil.SHA1Hash(Array.Empty<byte>());
 
 				var merged = streams[0];
 				for (var i = 1; i < streams.Count; i++)
@@ -321,25 +321,26 @@ namespace OpenRA
 		/// Initializes a new map created by the editor or importer.
 		/// The map will not receive a valid UID until after it has been saved and reloaded.
 		/// </summary>
-		public Map(ModData modData, ITerrainInfo terrainInfo, Size size)
+		public Map(ModData modData, ITerrainInfo terrainInfo, int width, int height)
 		{
 			this.modData = modData;
-			MapSize = size;
-			Grid = modData.GetOrCreate<MapGrid>();
+			var size = new Size(width, height);
+			Grid = modData.Manifest.Get<MapGrid>();
 
 			Title = "Name your map here";
 			Author = "Your name here";
 
+			MapSize = new int2(size);
 			Tileset = terrainInfo.Id;
 
 			// Empty rules that can be added to by the importers.
 			// Will be dropped on save if nothing is added to it
 			RuleDefinitions = new MiniYaml("");
 
-			Tiles = new CellLayer<TerrainTile>(Grid.Type, MapSize);
-			Resources = new CellLayer<ResourceTile>(Grid.Type, MapSize);
-			Height = new CellLayer<byte>(Grid.Type, MapSize);
-			Ramp = new CellLayer<byte>(Grid.Type, MapSize);
+			Tiles = new CellLayer<TerrainTile>(Grid.Type, size);
+			Resources = new CellLayer<ResourceTile>(Grid.Type, size);
+			Height = new CellLayer<byte>(Grid.Type, size);
+			Ramp = new CellLayer<byte>(Grid.Type, size);
 			Tiles.Clear(terrainInfo.DefaultTerrainTile);
 
 			if (Grid.MaximumTerrainHeight > 0)
@@ -367,15 +368,16 @@ namespace OpenRA
 			if (MapFormat < SupportedMapFormat)
 				throw new InvalidDataException($"Map format {MapFormat} is not supported.\n File: {package.Name}");
 
-			PlayerDefinitions = yaml.NodeWithKeyOrDefault("Players")?.Value.Nodes ?? [];
-			ActorDefinitions = yaml.NodeWithKeyOrDefault("Actors")?.Value.Nodes ?? [];
+			PlayerDefinitions = yaml.NodeWithKeyOrDefault("Players")?.Value.Nodes ?? ImmutableArray<MiniYamlNode>.Empty;
+			ActorDefinitions = yaml.NodeWithKeyOrDefault("Actors")?.Value.Nodes ?? ImmutableArray<MiniYamlNode>.Empty;
 
-			Grid = modData.GetOrCreate<MapGrid>();
+			Grid = modData.Manifest.Get<MapGrid>();
 
-			Tiles = new CellLayer<TerrainTile>(Grid.Type, MapSize);
-			Resources = new CellLayer<ResourceTile>(Grid.Type, MapSize);
-			Height = new CellLayer<byte>(Grid.Type, MapSize);
-			Ramp = new CellLayer<byte>(Grid.Type, MapSize);
+			var size = new Size(MapSize.X, MapSize.Y);
+			Tiles = new CellLayer<TerrainTile>(Grid.Type, size);
+			Resources = new CellLayer<ResourceTile>(Grid.Type, size);
+			Height = new CellLayer<byte>(Grid.Type, size);
+			Ramp = new CellLayer<byte>(Grid.Type, size);
 
 			using (var s = Package.GetStream("map.bin"))
 			{
@@ -383,9 +385,9 @@ namespace OpenRA
 				if (header.TilesOffset > 0)
 				{
 					s.Position = header.TilesOffset;
-					for (var i = 0; i < MapSize.Width; i++)
+					for (var i = 0; i < MapSize.X; i++)
 					{
-						for (var j = 0; j < MapSize.Height; j++)
+						for (var j = 0; j < MapSize.Y; j++)
 						{
 							var tile = s.ReadUInt16();
 							var index = s.ReadUInt8();
@@ -402,9 +404,9 @@ namespace OpenRA
 				if (header.ResourcesOffset > 0)
 				{
 					s.Position = header.ResourcesOffset;
-					for (var i = 0; i < MapSize.Width; i++)
+					for (var i = 0; i < MapSize.X; i++)
 					{
-						for (var j = 0; j < MapSize.Height; j++)
+						for (var j = 0; j < MapSize.Y; j++)
 						{
 							var type = s.ReadUInt8();
 							var density = s.ReadUInt8();
@@ -416,8 +418,8 @@ namespace OpenRA
 				if (header.HeightsOffset > 0)
 				{
 					s.Position = header.HeightsOffset;
-					for (var i = 0; i < MapSize.Width; i++)
-						for (var j = 0; j < MapSize.Height; j++)
+					for (var i = 0; i < MapSize.X; i++)
+						for (var j = 0; j < MapSize.Y; j++)
 							Height[new MPos(i, j)] = s.ReadUInt8().Clamp((byte)0, Grid.MaximumTerrainHeight);
 				}
 			}
@@ -453,7 +455,7 @@ namespace OpenRA
 			Sequences = new SequenceSet(this, modData, Tileset, SequenceDefinitions);
 
 			var tl = new MPos(0, 0).ToCPos(this);
-			var br = new MPos(MapSize.Width - 1, MapSize.Height - 1).ToCPos(this);
+			var br = new MPos(MapSize.X - 1, MapSize.Y - 1).ToCPos(this);
 			AllCells = new CellRegion(Grid.Type, tl, br);
 
 			var btl = new PPos(Bounds.Left, Bounds.Top);
@@ -514,7 +516,7 @@ namespace OpenRA
 			foreach (var cell in AllCells)
 			{
 				var uv = cell.ToMPos(Grid.Type);
-				cellProjection[uv] = [];
+				cellProjection[uv] = Array.Empty<PPos>();
 				inverseCellProjection[uv] = new List<MPos>(1);
 			}
 
@@ -530,7 +532,7 @@ namespace OpenRA
 			if (Grid.MaximumTerrainHeight == 0)
 			{
 				uv = cell.ToMPos(Grid.Type);
-				cellProjection[cell] = [(PPos)uv];
+				cellProjection[cell] = new[] { (PPos)uv };
 				var inverse = inverseCellProjection[uv];
 				inverse.Clear();
 				inverse.Add(uv);
@@ -605,7 +607,7 @@ namespace OpenRA
 			// Any changes to this function should be reflected when setting projectionSafeBounds.
 			var height = mapHeight[uv];
 			if (height == 0)
-				return [(PPos)uv];
+				return new[] { (PPos)uv };
 
 			// Odd-height ramps get bumped up a level to the next even height layer
 			if ((height & 1) == 1 && Ramp[uv] != 0)
@@ -682,13 +684,13 @@ namespace OpenRA
 				writer.Write(TileFormat);
 
 				// Size
-				writer.Write((ushort)MapSize.Width);
-				writer.Write((ushort)MapSize.Height);
+				writer.Write((ushort)MapSize.X);
+				writer.Write((ushort)MapSize.Y);
 
 				// Data offsets
 				const int TilesOffset = 17;
-				var heightsOffset = Grid.MaximumTerrainHeight > 0 ? 3 * MapSize.Width * MapSize.Height + 17 : 0;
-				var resourcesOffset = (Grid.MaximumTerrainHeight > 0 ? 4 : 3) * MapSize.Width * MapSize.Height + 17;
+				var heightsOffset = Grid.MaximumTerrainHeight > 0 ? 3 * MapSize.X * MapSize.Y + 17 : 0;
+				var resourcesOffset = (Grid.MaximumTerrainHeight > 0 ? 4 : 3) * MapSize.X * MapSize.Y + 17;
 
 				writer.Write((uint)TilesOffset);
 				writer.Write((uint)heightsOffset);
@@ -697,9 +699,9 @@ namespace OpenRA
 				// Tile data
 				if (TilesOffset != 0)
 				{
-					for (var i = 0; i < MapSize.Width; i++)
+					for (var i = 0; i < MapSize.X; i++)
 					{
-						for (var j = 0; j < MapSize.Height; j++)
+						for (var j = 0; j < MapSize.Y; j++)
 						{
 							var tile = Tiles[new MPos(i, j)];
 							writer.Write(tile.Type);
@@ -710,16 +712,16 @@ namespace OpenRA
 
 				// Height data
 				if (heightsOffset != 0)
-					for (var i = 0; i < MapSize.Width; i++)
-						for (var j = 0; j < MapSize.Height; j++)
+					for (var i = 0; i < MapSize.X; i++)
+						for (var j = 0; j < MapSize.Y; j++)
 							writer.Write(Height[new MPos(i, j)]);
 
 				// Resource data
 				if (resourcesOffset != 0)
 				{
-					for (var i = 0; i < MapSize.Width; i++)
+					for (var i = 0; i < MapSize.X; i++)
 					{
-						for (var j = 0; j < MapSize.Height; j++)
+						for (var j = 0; j < MapSize.Y; j++)
 						{
 							var tile = Resources[new MPos(i, j)];
 							writer.Write(tile.Type);
@@ -756,7 +758,7 @@ namespace OpenRA
 			var positions = new List<(MPos Uv, Color Color)>();
 			foreach (var actor in actors)
 			{
-				var s = new ActorReference(actor.Value.Value, actor.Value);
+				var s = new ActorReference(actor.Value.Value, actor.Value.ToDictionary());
 
 				var ai = Rules.Actors[actor.Value.Value];
 				var impsis = ai.TraitInfos<IMapPreviewSignatureInfo>();
@@ -1042,7 +1044,7 @@ namespace OpenRA
 			return (PPos)CellContaining(projectedPos).ToMPos(Grid.Type);
 		}
 
-		static readonly PPos[] NoProjectedCells = [];
+		static readonly PPos[] NoProjectedCells = Array.Empty<PPos>();
 		public PPos[] ProjectedCellsCovering(MPos uv)
 		{
 			if (!initializedCellProjection)
@@ -1062,7 +1064,7 @@ namespace OpenRA
 				InitializeCellProjection();
 
 			if (!inverseCellProjection.Contains(uv))
-				return [];
+				return new List<MPos>();
 
 			return inverseCellProjection[uv];
 		}
@@ -1087,15 +1089,16 @@ namespace OpenRA
 			var oldMapResources = Resources;
 			var oldMapHeight = Height;
 			var oldMapRamp = Ramp;
+			var newSize = new Size(width, height);
 
-			MapSize = new Size(width, height);
-			Tiles = CellLayer.Resize(oldMapTiles, MapSize, oldMapTiles[MPos.Zero]);
-			Resources = CellLayer.Resize(oldMapResources, MapSize, oldMapResources[MPos.Zero]);
-			Height = CellLayer.Resize(oldMapHeight, MapSize, oldMapHeight[MPos.Zero]);
-			Ramp = CellLayer.Resize(oldMapRamp, MapSize, oldMapRamp[MPos.Zero]);
+			Tiles = CellLayer.Resize(oldMapTiles, newSize, oldMapTiles[MPos.Zero]);
+			Resources = CellLayer.Resize(oldMapResources, newSize, oldMapResources[MPos.Zero]);
+			Height = CellLayer.Resize(oldMapHeight, newSize, oldMapHeight[MPos.Zero]);
+			Ramp = CellLayer.Resize(oldMapRamp, newSize, oldMapRamp[MPos.Zero]);
+			MapSize = new int2(newSize);
 
 			var tl = new MPos(0, 0);
-			var br = new MPos(MapSize.Width - 1, MapSize.Height - 1);
+			var br = new MPos(MapSize.X - 1, MapSize.Y - 1);
 			AllCells = new CellRegion(Grid.Type, tl.ToCPos(this), br.ToCPos(this));
 			SetBounds(new PPos(tl.U + 1, tl.V + 1), new PPos(br.U - 1, br.V - 1));
 		}
@@ -1142,11 +1145,6 @@ namespace OpenRA
 		}
 
 		public byte GetTerrainIndex(CPos cell)
-		{
-			return GetTerrainIndex(cell.ToMPos(this));
-		}
-
-		public byte GetTerrainIndex(MPos uv)
 		{
 			// Lazily initialize a cache for terrain indexes.
 			if (cachedTerrainIndexes == null)
@@ -1155,6 +1153,7 @@ namespace OpenRA
 				cachedTerrainIndexes.Clear(InvalidCachedTerrainIndex);
 			}
 
+			var uv = cell.ToMPos(this);
 			var terrainIndex = cachedTerrainIndexes[uv];
 
 			// PERF: Cache terrain indexes per cell on demand.
@@ -1169,12 +1168,7 @@ namespace OpenRA
 
 		public TerrainTypeInfo GetTerrainInfo(CPos cell)
 		{
-			return GetTerrainInfo(cell.ToMPos(this));
-		}
-
-		public TerrainTypeInfo GetTerrainInfo(MPos uv)
-		{
-			return Rules.TerrainInfo.TerrainTypes[GetTerrainIndex(uv)];
+			return Rules.TerrainInfo.TerrainTypes[GetTerrainIndex(cell)];
 		}
 
 		public CPos Clamp(CPos cell)

OpenRA.Game/Map/MapCache.cs

@@ -14,13 +14,13 @@ using System.Collections;
 using System.Collections.Generic;
 using System.IO;
 using System.Linq;
+using System.Text;
 using System.Threading;
 using System.Threading.Tasks;
 using OpenRA.FileSystem;
 using OpenRA.Graphics;
 using OpenRA.Primitives;
 using OpenRA.Support;
-using FS = OpenRA.FileSystem.FileSystem;
 
 namespace OpenRA
 {
@@ -28,27 +28,26 @@ namespace OpenRA
 	{
 		public static readonly MapPreview UnknownMap = new(null, null, MapGridType.Rectangular, null);
 		public IReadOnlyDictionary<IReadOnlyPackage, MapClassification> MapLocations => mapLocations;
-		readonly Dictionary<IReadOnlyPackage, MapClassification> mapLocations = [];
+		readonly Dictionary<IReadOnlyPackage, MapClassification> mapLocations = new();
 		public bool LoadPreviewImages = true;
 
-		readonly Manifest manifest;
-		readonly FS modFiles;
-		Cache<string, MapPreview> previews;
+		readonly Cache<string, MapPreview> previews;
+		readonly ModData modData;
 		readonly SheetBuilder sheetBuilder;
 		Thread previewLoaderThread;
 		bool previewLoaderThreadShutDown = true;
 		readonly object syncRoot = new();
-		readonly Queue<MapPreview> generateMinimap = [];
+		readonly Queue<MapPreview> generateMinimap = new();
 
-		public HashSet<string> StringPool { get; } = [];
+		public HashSet<string> StringPool { get; } = new();
 
-		readonly List<MapDirectoryTracker> mapDirectoryTrackers = [];
+		readonly List<MapDirectoryTracker> mapDirectoryTrackers = new();
 
 		/// <summary>
 		/// The most recently modified or loaded map at runtime.
 		/// </summary>
 		public string LastModifiedMap { get; private set; } = null;
-		readonly Dictionary<string, string> mapUpdates = [];
+		readonly Dictionary<string, string> mapUpdates = new();
 
 		string lastLoadedLastModifiedMap;
 
@@ -68,11 +67,13 @@ namespace OpenRA
 			return null;
 		}
 
-		public MapCache(Manifest manifest, FS modFiles)
+		public MapCache(ModData modData)
 		{
-			this.manifest = manifest;
-			this.modFiles = modFiles;
-			sheetBuilder = new SheetBuilder(SheetType.BGRA, manifest.RendererConstants.MapPreviewSheetSize);
+			this.modData = modData;
+
+			var gridType = Exts.Lazy(() => modData.Manifest.Get<MapGrid>().Type);
+			previews = new Cache<string, MapPreview>(uid => new MapPreview(modData, uid, gridType.Value, this));
+			sheetBuilder = new SheetBuilder(SheetType.BGRA);
 		}
 
 		public void UpdateMaps()
@@ -81,21 +82,20 @@ namespace OpenRA
 				tracker.UpdateMaps(this);
 		}
 
-		public void LoadMaps(ModData modData)
+		public void LoadMaps()
 		{
 			// Utility mod that does not support maps
-			if (manifest.MapFolders.Count == 0)
+			if (!modData.Manifest.Contains<MapGrid>())
 				return;
 
-			var gridType = modData.GetOrCreate<MapGrid>().Type;
-			previews = new Cache<string, MapPreview>(uid => new MapPreview(modData, uid, gridType, this));
+			var mapGrid = modData.Manifest.Get<MapGrid>();
 
 			// Enumerate map directories
-			foreach (var kv in manifest.MapFolders)
+			foreach (var kv in modData.Manifest.MapFolders)
 			{
 				var name = kv.Key;
 				var classification = string.IsNullOrEmpty(kv.Value)
-					? MapClassification.Unknown : Enum.Parse<MapClassification>(kv.Value);
+					? MapClassification.Unknown : Enum<MapClassification>.Parse(kv.Value);
 
 				IReadOnlyPackage package;
 				var optional = name.StartsWith('~');
@@ -110,7 +110,7 @@ namespace OpenRA
 					if (resolved.StartsWith(Platform.SupportDir, StringComparison.Ordinal) && !File.Exists(resolved))
 						Directory.CreateDirectory(resolved);
 
-					package = modFiles.OpenPackage(name);
+					package = modData.ModFiles.OpenPackage(name);
 				}
 				catch
 				{
@@ -121,38 +121,42 @@ namespace OpenRA
 				}
 
 				mapLocations.Add(package, classification);
-				mapDirectoryTrackers.Add(new MapDirectoryTracker(package, classification));
+				mapDirectoryTrackers.Add(new MapDirectoryTracker(mapGrid, package, classification));
 			}
 
 			// PERF: Load the mod YAML once outside the loop, and reuse it when resolving each maps custom YAML.
 			var modDataRules = modData.GetRulesYaml();
 			foreach (var kv in MapLocations)
+			{
 				foreach (var map in kv.Key.Contents)
-					LoadMapInternal(map, kv.Key, kv.Value, null, gridType, modDataRules);
+					LoadMapInternal(map, kv.Key, kv.Value, mapGrid, null, modDataRules);
+			}
 
 			// We only want to track maps in runtime, not at loadtime
 			LastModifiedMap = null;
 		}
 
-		public void LoadMap(string map, IReadOnlyPackage package, MapClassification classification, string oldMap)
+		public void LoadMap(string map, IReadOnlyPackage package, MapClassification classification, MapGrid mapGrid, string oldMap)
 		{
-			LoadMapInternal(map, package, classification, oldMap);
+			LoadMapInternal(map, package, classification, mapGrid, oldMap, null);
 		}
 
-		void LoadMapInternal(string map, IReadOnlyPackage package, MapClassification classification, string oldMap,
-			MapGridType? gridType = null, MiniYamlNode[][] modDataRules = null)
+		void LoadMapInternal(string map, IReadOnlyPackage package, MapClassification classification, MapGrid mapGrid, string oldMap,
+			IEnumerable<List<MiniYamlNode>> modDataRules)
 		{
 			IReadOnlyPackage mapPackage = null;
 			try
 			{
 				using (new PerfTimer(map))
 				{
-					mapPackage = package.OpenPackage(map, modFiles);
+					mapPackage = package.OpenPackage(map, modData.ModFiles);
 					if (mapPackage != null)
 					{
 						var uid = Map.ComputeUID(mapPackage);
-						previews[uid].UpdateFromMapWithoutOwningPackage(mapPackage, package, classification, gridType, modDataRules);
-						mapPackage.Dispose();
+						previews[uid].UpdateFromMap(mapPackage, package, classification, modData.Manifest.MapCompatibility, mapGrid.Type, modDataRules);
+
+						// Freeing the package to save memory if there is a lot of Maps
+						previews[uid].DisposePackage();
 
 						if (oldMap != uid)
 						{
@@ -177,8 +181,12 @@ namespace OpenRA
 
 		public IEnumerable<IReadWritePackage> EnumerateMapDirPackages(MapClassification classification = MapClassification.System)
 		{
+			// Utility mod that does not support maps
+			if (!modData.Manifest.Contains<MapGrid>())
+				yield break;
+
 			// Enumerate map directories
-			foreach (var kv in manifest.MapFolders)
+			foreach (var kv in modData.Manifest.MapFolders)
 			{
 				if (!Enum.TryParse(kv.Value, out MapClassification packageClassification))
 					continue;
@@ -196,7 +204,7 @@ namespace OpenRA
 				if (resolved.StartsWith(Platform.SupportDir, StringComparison.Ordinal) && (!Directory.Exists(resolved) || !File.Exists(resolved)))
 					continue;
 
-				using (var package = (IReadWritePackage)modFiles.OpenPackage(name))
+				using (var package = (IReadWritePackage)modData.ModFiles.OpenPackage(name))
 					yield return package;
 			}
 		}
@@ -216,7 +224,7 @@ namespace OpenRA
 
 			foreach (var mapDirPackage in mapDirPackages)
 				foreach (var map in mapDirPackage.Contents)
-					if (mapDirPackage.OpenPackage(map, modFiles) is IReadWritePackage mapPackage)
+					if (mapDirPackage.OpenPackage(map, modData.ModFiles) is IReadWritePackage mapPackage)
 						yield return mapPackage;
 		}
 
@@ -231,37 +239,67 @@ namespace OpenRA
 				.ToList();
 
 			foreach (var uid in queryUids)
-				previews[uid].BeginRemoteSearch();
+				previews[uid].UpdateRemoteSearch(MapStatus.Searching, null, null);
 
 			Task.Run(async () =>
 			{
 				var client = HttpClientFactory.Create();
 				var stringPool = new HashSet<string>(); // Reuse common strings in YAML
+				var buffer = new StringBuilder();
 
 				// Limit each query to 50 maps at a time to avoid request size limits
-				foreach (var batchUids in queryUids.Chunk(50))
+				for (var i = 0; i < queryUids.Count; i += 50)
 				{
+					var batchUids = queryUids.Skip(i).Take(50).ToList();
 					var url = repositoryUrl + "hash/" + string.Join(",", batchUids) + "/yaml";
+
 					using (new PerfTimer("RemoteMapDetails"))
 					{
 						try
 						{
-							var result = await client.GetStreamAsync(url);
-							foreach (var kv in MiniYaml.FromStream(result, url, stringPool: stringPool))
-								previews[kv.Key].CompleteRemoteSearch(kv.Value, mapDetailsReceived);
+							await using (var resultStream = await client.GetStreamAsync(url))
+							{
+								using (var resultReader = new StreamReader(resultStream))
+								{
+									while (true)
+									{
+										var line = await resultReader.ReadLineAsync();
+										if (line == null || !line.StartsWith('\t'))
+										{
+											var yaml = MiniYaml.FromString(buffer.ToString(), url, stringPool: stringPool);
+											buffer.Clear();
+											foreach (var kv in yaml)
+												previews[kv.Key].UpdateRemoteSearch(MapStatus.DownloadAvailable, kv.Value, modData.Manifest.MapCompatibility, mapDetailsReceived);
+
+											if (line == null)
+												break;
+										}
+
+										buffer.Append(line);
+										buffer.Append('\n');
+									}
+								}
+							}
+
+							foreach (var uid in batchUids)
+							{
+								var p = previews[uid];
+								if (p.Status != MapStatus.DownloadAvailable)
+									p.UpdateRemoteSearch(MapStatus.Unavailable, null, null);
+							}
 						}
 						catch (Exception e)
 						{
 							Log.Write("debug", "Remote map query failed with error:");
 							Log.Write("debug", e);
 							Log.Write("debug", $"URL was: {url}");
-						}
 
 							foreach (var uid in batchUids)
 							{
 								var p = previews[uid];
-							if (p.Status == MapStatus.Searching)
-								p.CompleteRemoteSearch(null, mapQueryFailed);
+								p.UpdateRemoteSearch(MapStatus.Unavailable, null, null);
+								mapQueryFailed?.Invoke(p);
+							}
 						}
 					}
 				}
@@ -328,9 +366,7 @@ namespace OpenRA
 			}
 
 			// Release the buffer by forcing changes to be written out to the texture, allowing the buffer to be reclaimed by GC.
-			if (sheetBuilder.Current != null)
 			Game.RunAfterTick(sheetBuilder.Current.ReleaseBuffer);
-
 			Log.Write("debug", "MapCache.LoadAsyncInternal ended");
 		}
 

OpenRA.Game/Map/MapDirectoryTracker.cs

@@ -20,24 +20,26 @@ namespace OpenRA
 	public sealed class MapDirectoryTracker : IDisposable
 	{
 		readonly FileSystemWatcher watcher;
+		readonly MapGrid mapGrid;
 		readonly IReadOnlyPackage package;
 		readonly MapClassification classification;
 
 		enum MapAction { Add, Delete, Update }
-		readonly Dictionary<string, MapAction> mapActionQueue = [];
+		readonly Dictionary<string, MapAction> mapActionQueue = new();
 
 		bool dirty = false;
 
-		public MapDirectoryTracker(IReadOnlyPackage package, MapClassification classification)
+		public MapDirectoryTracker(MapGrid mapGrid, IReadOnlyPackage package, MapClassification classification)
 		{
+			this.mapGrid = mapGrid;
 			this.package = package;
 			this.classification = classification;
 
 			watcher = new FileSystemWatcher(package.Name);
-			watcher.Changed += (_, e) => AddMapAction(MapAction.Update, e.FullPath);
-			watcher.Created += (_, e) => AddMapAction(MapAction.Add, e.FullPath);
-			watcher.Deleted += (_, e) => AddMapAction(MapAction.Delete, e.FullPath);
-			watcher.Renamed += (_, e) => AddMapAction(MapAction.Add, e.FullPath, e.OldFullPath);
+			watcher.Changed += (object sender, FileSystemEventArgs e) => AddMapAction(MapAction.Update, e.FullPath);
+			watcher.Created += (object sender, FileSystemEventArgs e) => AddMapAction(MapAction.Add, e.FullPath);
+			watcher.Deleted += (object sender, FileSystemEventArgs e) => AddMapAction(MapAction.Delete, e.FullPath);
+			watcher.Renamed += (object sender, RenamedEventArgs e) => AddMapAction(MapAction.Add, e.FullPath, e.OldFullPath);
 
 			watcher.IncludeSubdirectories = true;
 			watcher.EnableRaisingEvents = true;
@@ -84,7 +86,7 @@ namespace OpenRA
 				dirty = false;
 				foreach (var mapAction in mapActionQueue)
 				{
-					var map = mapcache.FirstOrDefault(x => x.Path == mapAction.Key && x.Status == MapStatus.Available);
+					var map = mapcache.FirstOrDefault(x => x.PackageName == mapAction.Key && x.Status == MapStatus.Available);
 					if (map != null)
 					{
 						if (mapAction.Value == MapAction.Delete)
@@ -96,7 +98,7 @@ namespace OpenRA
 						{
 							Console.WriteLine(mapAction.Key + " was updated");
 							map.Invalidate();
-							mapcache.LoadMap(mapAction.Key.Replace(package.Name + Path.DirectorySeparatorChar, ""), package, classification, map.Uid);
+							mapcache.LoadMap(mapAction.Key.Replace(package.Name + Path.DirectorySeparatorChar, ""), package, classification, mapGrid, map.Uid);
 						}
 					}
 					else
@@ -104,7 +106,7 @@ namespace OpenRA
 						if (mapAction.Value != MapAction.Delete)
 						{
 							Console.WriteLine(mapAction.Key + " was added");
-							mapcache.LoadMap(mapAction.Key.Replace(package?.Name + Path.DirectorySeparatorChar, ""), package, classification, null);
+							mapcache.LoadMap(mapAction.Key.Replace(package?.Name + Path.DirectorySeparatorChar, ""), package, classification, mapGrid, null);
 						}
 					}
 				}

OpenRA.Game/Map/MapGenerationArgs.cs

@@ -1,58 +0,0 @@
-#region Copyright & License Information
-/*
- * Copyright (c) The OpenRA Developers and Contributors
- * This file is part of OpenRA, which is free software. It is made
- * available to you under the terms of the GNU General Public License
- * as published by the Free Software Foundation, either version 3 of
- * the License, or (at your option) any later version. For more
- * information, see COPYING.
- */
-#endregion
-
-using System.Collections.Generic;
-using OpenRA.Primitives;
-
-namespace OpenRA
-{
-	public class MapGenerationArgs
-	{
-		[FieldLoader.Require]
-		public string Uid = null;
-
-		[FieldLoader.Require]
-		public string Generator = null;
-
-		[FieldLoader.Require]
-		public string Tileset = null;
-
-		[FieldLoader.Require]
-		public Size Size = default;
-
-		[FieldLoader.Require]
-		public string Title = null;
-
-		[FieldLoader.Require]
-		public string Author = null;
-
-		[FieldLoader.LoadUsing(nameof(LoadSettings))]
-		public MiniYaml Settings = null;
-		static MiniYaml LoadSettings(MiniYaml yaml)
-		{
-			return yaml.NodeWithKey("Settings").Value;
-		}
-
-		public List<MiniYamlNode> Serialize()
-		{
-			return
-			[
-				new("Uid", Uid),
-				new("Generator", Generator),
-				new("Tileset", Tileset),
-				new("Size", FieldSaver.FormatValue(Size)),
-				new("Settings", Settings),
-				new("Title", Title),
-				new("Author", Author)
-			];
-		}
-	}
-}

OpenRA.Game/Map/MapGrid.cs

@@ -10,9 +10,9 @@
 #endregion
 
 using System.Collections.Generic;
-using System.Collections.Immutable;
 using System.IO;
 using System.Linq;
+using OpenRA.Primitives;
 using OpenRA.Traits;
 
 namespace OpenRA
@@ -25,8 +25,8 @@ namespace OpenRA
 	public readonly struct CellRamp
 	{
 		public readonly int CenterHeightOffset;
-		public readonly ImmutableArray<WVec> Corners;
-		public readonly ImmutableArray<ImmutableArray<WVec>> Polygons;
+		public readonly WVec[] Corners;
+		public readonly WVec[][] Polygons;
 		public readonly WRot Orientation;
 
 		public CellRamp(MapGridType type, WRot orientation,
@@ -37,43 +37,43 @@ namespace OpenRA
 			Orientation = orientation;
 			if (type == MapGridType.RectangularIsometric)
 			{
-				Corners =
-				[
+				Corners = new[]
+				{
 					new WVec(0, -724, 724 * (int)tl),
 					new WVec(724, 0, 724 * (int)tr),
 					new WVec(0, 724, 724 * (int)br),
 					new WVec(-724, 0, 724 * (int)bl),
-				];
+				};
 			}
 			else
 			{
-				Corners =
-				[
+				Corners = new[]
+				{
 					new WVec(-512, -512, 512 * (int)tl),
 					new WVec(512, -512, 512 * (int)tr),
 					new WVec(512, 512, 512 * (int)br),
 					new WVec(-512, 512, 512 * (int)bl)
-				];
+				};
 			}
 
 			if (split == RampSplit.X)
 			{
-				Polygons =
-				[
-					[Corners[0], Corners[1], Corners[3]],
-					[Corners[1], Corners[2], Corners[3]]
-				];
+				Polygons = new[]
+				{
+					new[] { Corners[0], Corners[1], Corners[3] },
+					new[] { Corners[1], Corners[2], Corners[3] }
+				};
 			}
 			else if (split == RampSplit.Y)
 			{
-				Polygons =
-				[
-					[Corners[0], Corners[1], Corners[2]],
-					[Corners[0], Corners[2], Corners[3]]
-				];
+				Polygons = new[]
+				{
+					new[] { Corners[0], Corners[1], Corners[2] },
+					new[] { Corners[0], Corners[2], Corners[3] }
+				};
 			}
 			else
-				Polygons = [Corners];
+				Polygons = new[] { Corners };
 
 			// Initial value must be assigned before HeightOffset can be called
 			CenterHeightOffset = 0;
@@ -84,11 +84,10 @@ namespace OpenRA
 		{
 			// Enumerate over the polygons, assuming that they are triangles
 			// If the ramp is not split we will take the first three vertices of the corners as a valid triangle
-			int u;
-			int v;
-			ImmutableArray<WVec> p;
-			var i = 0;
-			do
+			WVec[] p = null;
+			var u = 0;
+			var v = 0;
+			for (var i = 0; i < Polygons.Length; i++)
 			{
 				p = Polygons[i];
 				u = ((p[1].Y - p[2].Y) * (dX - p[2].X) - (p[1].X - p[2].X) * (dY - p[2].Y)) / 1024;
@@ -97,10 +96,7 @@ namespace OpenRA
 				// Point is within the triangle if 0 <= u,v <= 1024
 				if (u >= 0 && u <= 1024 && v >= 0 && v <= 1024)
 					break;
-
-				i++;
 			}
-			while (i < Polygons.Length);
 
 			// Calculate w from u,v and interpolate height
 			return (u * p[0].Z + v * p[1].Z + (1024 - u - v) * p[2].Z) / 1024;
@@ -110,6 +106,7 @@ namespace OpenRA
 	public class MapGrid : IGlobalModData
 	{
 		public readonly MapGridType Type = MapGridType.Rectangular;
+		public readonly Size TileSize = new(24, 24);
 		public readonly byte MaximumTerrainHeight = 0;
 		public readonly SubCell DefaultSubCell = (SubCell)byte.MaxValue;
 
@@ -117,19 +114,19 @@ namespace OpenRA
 
 		public readonly bool EnableDepthBuffer = false;
 
-		public readonly ImmutableArray<WVec> SubCellOffsets =
-		[
+		public readonly WVec[] SubCellOffsets =
+		{
 			new(0, 0, 0),       // full cell - index 0
 			new(-299, -256, 0), // top left - index 1
 			new(256, -256, 0),  // top right - index 2
 			new(0, 0, 0),       // center - index 3
 			new(-299, 256, 0),  // bottom left - index 4
 			new(256, 256, 0),   // bottom right - index 5
-		];
+		};
 
-		public ImmutableArray<CellRamp> Ramps { get; }
+		public CellRamp[] Ramps { get; }
 
-		internal readonly ImmutableArray<ImmutableArray<CVec>> TilesByDistance;
+		internal readonly CVec[][] TilesByDistance;
 
 		public int TileScale { get; }
 
@@ -162,9 +159,8 @@ namespace OpenRA
 			var halfBackward = -halfForward;
 
 			// Slope types are hardcoded following the convention from the TS and RA2 map format
-			Ramps =
-			[
-
+			Ramps = new[]
+			{
 				// Flat
 				new CellRamp(Type, WRot.None),
 
@@ -197,16 +193,16 @@ namespace OpenRA
 				new CellRamp(Type, WRot.None, tl: RampCornerHeight.Half, br: RampCornerHeight.Half, split: RampSplit.Y),
 				new CellRamp(Type, WRot.None, tr: RampCornerHeight.Half, bl: RampCornerHeight.Half, split: RampSplit.X),
 				new CellRamp(Type, WRot.None, tl: RampCornerHeight.Half, br: RampCornerHeight.Half, split: RampSplit.X),
-			];
+			};
 
 			TilesByDistance = CreateTilesByDistance();
 		}
 
-		ImmutableArray<ImmutableArray<CVec>> CreateTilesByDistance()
+		CVec[][] CreateTilesByDistance()
 		{
 			var ts = new List<CVec>[MaximumTileSearchRange + 1];
 			for (var i = 0; i < MaximumTileSearchRange + 1; i++)
-				ts[i] = [];
+				ts[i] = new List<CVec>();
 
 			for (var j = -MaximumTileSearchRange; j <= MaximumTileSearchRange; j++)
 				for (var i = -MaximumTileSearchRange; i <= MaximumTileSearchRange; i++)
@@ -238,7 +234,7 @@ namespace OpenRA
 				});
 			}
 
-			return ts.Select(list => list.ToImmutableArray()).ToImmutableArray();
+			return ts.Select(list => list.ToArray()).ToArray();
 		}
 
 		public WVec OffsetOfSubCell(SubCell subCell)

OpenRA.Game/Map/MapPlayers.cs

@@ -10,7 +10,6 @@
 #endregion
 
 using System.Collections.Generic;
-using System.Collections.Immutable;
 using System.Linq;
 using OpenRA.Traits;
 
@@ -25,7 +24,7 @@ namespace OpenRA
 		public readonly Dictionary<string, PlayerReference> Players;
 
 		public MapPlayers()
-			: this([]) { }
+			: this(new List<MiniYamlNode>()) { }
 
 		public MapPlayers(IEnumerable<MiniYamlNode> playerDefinitions)
 		{
@@ -55,7 +54,7 @@ namespace OpenRA
 						Name = "Creeps",
 						Faction = firstFaction,
 						NonCombatant = true,
-						Enemies = Exts.MakeArray(playerCount, i => $"Multi{i}").ToImmutableArray()
+						Enemies = Exts.MakeArray(playerCount, i => $"Multi{i}")
 					}
 				}
 			};
@@ -67,7 +66,7 @@ namespace OpenRA
 					Name = $"Multi{index}",
 					Faction = "Random",
 					Playable = true,
-					Enemies = ["Creeps"]
+					Enemies = new[] { "Creeps" }
 				};
 				Players.Add(p.Name, p);
 			}

OpenRA.Game/Map/MapPreview.cs

@@ -11,7 +11,6 @@
 
 using System;
 using System.Collections.Generic;
-using System.Collections.Immutable;
 using System.Diagnostics.CodeAnalysis;
 using System.IO;
 using System.Linq;
@@ -24,11 +23,10 @@ using OpenRA.FileSystem;
 using OpenRA.Graphics;
 using OpenRA.Primitives;
 using OpenRA.Support;
-using OpenRA.Traits;
 
 namespace OpenRA
 {
-	public enum MapStatus { Available, Unavailable, Searching, DownloadAvailable, Downloading, DownloadError, Generatable, Generating }
+	public enum MapStatus { Available, Unavailable, Searching, DownloadAvailable, Downloading, DownloadError }
 
 	// Used for grouping maps in the UI
 	[Flags]
@@ -37,8 +35,7 @@ namespace OpenRA
 		Unknown = 0,
 		System = 1,
 		User = 2,
-		Remote = 4,
-		Generated = 8
+		Remote = 4
 	}
 
 	[SuppressMessage("StyleCop.CSharp.NamingRules",
@@ -51,10 +48,10 @@ namespace OpenRA
 	{
 		public readonly string title;
 		public readonly string author;
-		public readonly ImmutableArray<string> categories;
+		public readonly string[] categories;
 		public readonly int players;
 		public readonly Rectangle bounds;
-		public readonly ImmutableArray<short> spawnpoints = [];
+		public readonly short[] spawnpoints = Array.Empty<short>();
 		public readonly MapGridType map_grid_type;
 		public readonly string minimap;
 		public readonly bool downloading;
@@ -72,12 +69,12 @@ namespace OpenRA
 		{
 			public int MapFormat;
 			public string Title;
-			public ImmutableArray<string> Categories;
+			public string[] Categories;
 			public string Author;
 			public string TileSet;
 			public MapPlayers Players;
 			public int PlayerCount;
-			public ImmutableArray<CPos> SpawnPoints;
+			public CPos[] SpawnPoints;
 			public MapGridType GridType;
 			public Rectangle Bounds;
 			public Png Preview;
@@ -85,7 +82,6 @@ namespace OpenRA
 			public MapClassification Class;
 			public MapVisibility Visibility;
 			public DateTime ModifiedDate;
-			public MapGenerationArgs GenerationArgs;
 
 			public MiniYaml RuleDefinitions;
 			public MiniYaml WeaponDefinitions;
@@ -117,7 +113,7 @@ namespace OpenRA
 				return key == "world" || key == "player";
 			}
 
-			public void SetCustomRules(ModData modData, IReadOnlyFileSystem fileSystem, Dictionary<string, MiniYaml> yaml, MiniYamlNode[][] modDataRules)
+			public void SetCustomRules(ModData modData, IReadOnlyFileSystem fileSystem, Dictionary<string, MiniYaml> yaml, IEnumerable<List<MiniYamlNode>> modDataRules)
 			{
 				RuleDefinitions = LoadRuleSection(yaml, "Rules");
 				WeaponDefinitions = LoadRuleSection(yaml, "Weapons");
@@ -132,9 +128,9 @@ namespace OpenRA
 				{
 					if (FluentMessageDefinitions != null)
 					{
-						var files = ImmutableArray<string>.Empty;
+						var files = Array.Empty<string>();
 						if (FluentMessageDefinitions.Value != null)
-							files = FieldLoader.GetValue<ImmutableArray<string>>("value", FluentMessageDefinitions.Value);
+							files = FieldLoader.GetValue<string[]>("value", FluentMessageDefinitions.Value);
 
 						string text = null;
 						if (FluentMessageDefinitions.Nodes.Length > 0)
@@ -160,8 +156,8 @@ namespace OpenRA
 						var files = Enumerable.Empty<string>();
 						if (RuleDefinitions.Value != null)
 						{
-							var mapFiles = FieldLoader.GetValue<ImmutableArray<string>>("value", RuleDefinitions.Value);
-							files = files.Concat(mapFiles);
+							var mapFiles = FieldLoader.GetValue<string[]>("value", RuleDefinitions.Value);
+							files = files.Append(mapFiles);
 						}
 
 						var stringPool = new HashSet<string>(); // Reuse common strings in YAML
@@ -199,26 +195,22 @@ namespace OpenRA
 			}
 		}
 
-		readonly object syncRoot = new();
+		static readonly CPos[] NoSpawns = Array.Empty<CPos>();
 		readonly MapCache cache;
 		readonly ModData modData;
-		IReadOnlyPackage package;
 
 		public readonly string Uid;
-
-		public string Path { get; private set; }
-
-		void LoadPackage()
+		public string PackageName { get; private set; }
+		IReadOnlyPackage package;
+		public IReadOnlyPackage Package
 		{
-			if (package == null && parentPackage != null)
-				package = parentPackage.OpenPackage(Path, modData.ModFiles);
+			get
+			{
+				package ??= parentPackage.OpenPackage(PackageName, modData.ModFiles);
+				return package;
 			}
 
-		public Map ToMap()
-		{
-			LoadPackage();
-			using (new PerfTimer("Map"))
-				return new Map(modData, package);
+			private set => package = value;
 		}
 
 		IReadOnlyPackage parentPackage;
@@ -227,12 +219,12 @@ namespace OpenRA
 
 		public int MapFormat => innerData.MapFormat;
 		public string Title => innerData.Title;
-		public ImmutableArray<string> Categories => innerData.Categories;
+		public string[] Categories => innerData.Categories;
 		public string Author => innerData.Author;
 		public string TileSet => innerData.TileSet;
 		public MapPlayers Players => innerData.Players;
 		public int PlayerCount => innerData.PlayerCount;
-		public ImmutableArray<CPos> SpawnPoints => innerData.SpawnPoints;
+		public CPos[] SpawnPoints => innerData.SpawnPoints;
 		public MapGridType GridType => innerData.GridType;
 		public Rectangle Bounds => innerData.Bounds;
 		public Png Preview => innerData.Preview;
@@ -248,8 +240,6 @@ namespace OpenRA
 		public ActorInfo PlayerActorInfo => innerData.PlayerActorInfo;
 		public DateTime ModifiedDate => innerData.ModifiedDate;
 
-		public MapGenerationArgs GenerationArgs => innerData.GenerationArgs;
-
 		public long DownloadBytes { get; private set; }
 		public int DownloadPercentage { get; private set; }
 
@@ -327,12 +317,12 @@ namespace OpenRA
 			{
 				MapFormat = 0,
 				Title = "Unknown Map",
-				Categories = ["Unknown"],
+				Categories = new[] { "Unknown" },
 				Author = "Unknown Author",
 				TileSet = "unknown",
 				Players = null,
 				PlayerCount = 0,
-				SpawnPoints = [],
+				SpawnPoints = NoSpawns,
 				GridType = gridType,
 				Bounds = Rectangle.Empty,
 				Preview = null,
@@ -342,28 +332,57 @@ namespace OpenRA
 			};
 		}
 
-		/// <summary>
-		/// Updates internal state from a map without taking ownership of its package.
-		/// A new copy of the map package will be opened lazily when needed.
-		/// </summary>
-		public void UpdateFromMapWithoutOwningPackage(IReadOnlyPackage p, IReadOnlyPackage parent, MapClassification classification,
-			MapGridType? gridType = null, MiniYamlNode[][] modDataRules = null)
+		// For linting purposes only!
+		public MapPreview(Map map, ModData modData)
 		{
-			UpdateFromMap(p, classification, gridType, modDataRules);
-			parentPackage = parent;
-			package = null;
+			this.modData = modData;
+			cache = modData.MapCache;
+
+			Uid = map.Uid;
+			PackageName = map.Package.Name;
+
+			var mapPlayers = new MapPlayers(map.PlayerDefinitions);
+			var spawns = new List<CPos>();
+			foreach (var kv in map.ActorDefinitions.Where(d => d.Value.Value == "mpspawn"))
+			{
+				var s = new ActorReference(kv.Value.Value, kv.Value.ToDictionary());
+				spawns.Add(s.Get<LocationInit>().Value);
 			}
 
-		/// <summary>
-		/// Updates internal state from a map and takes ownership of its package.
-		/// The package remains in memory and must not be disposed.
-		/// </summary>
-		public void UpdateFromMap(IReadOnlyPackage p, MapClassification classification,
-			MapGridType? gridType = null, MiniYamlNode[][] modDataRules = null)
+			innerData = new InnerData
 			{
-			Path = p.Name;
-			package = p;
+				MapFormat = map.MapFormat,
+				Title = map.Title,
+				Categories = map.Categories,
+				Author = map.Author,
+				TileSet = map.Tileset,
+				Players = mapPlayers,
+				PlayerCount = mapPlayers.Players.Count(x => x.Value.Playable),
+				SpawnPoints = spawns.ToArray(),
+				GridType = map.Grid.Type,
+				Bounds = map.Bounds,
+				Preview = null,
+				Status = MapStatus.Available,
+				Class = MapClassification.Unknown,
+				Visibility = map.Visibility,
+			};
 
+			innerData.SetCustomRules(modData, this, new Dictionary<string, MiniYaml>()
+			{
+				{ "Rules", map.RuleDefinitions },
+				{ "FluentMessages", map.FluentMessageDefinitions },
+				{ "Weapons", map.WeaponDefinitions },
+				{ "Voices", map.VoiceDefinitions },
+				{ "Music", map.MusicDefinitions },
+				{ "Notifications", map.NotificationDefinitions },
+				{ "Sequences", map.SequenceDefinitions },
+				{ "ModelSequences", map.ModelSequenceDefinitions }
+			}, null);
+		}
+
+		public void UpdateFromMap(IReadOnlyPackage p, IReadOnlyPackage parent, MapClassification classification,
+			string[] mapCompatibility, MapGridType gridType, IEnumerable<List<MiniYamlNode>> modDataRules)
+		{
 			Dictionary<string, MiniYaml> yaml;
 			using (var yamlStream = p.GetStream("map.yaml"))
 			{
@@ -373,9 +392,12 @@ namespace OpenRA
 				yaml = new MiniYaml(null, MiniYaml.FromStream(yamlStream, $"{p.Name}:map.yaml", stringPool: cache.StringPool)).ToDictionary();
 			}
 
+			PackageName = p.Name;
+			parentPackage = parent;
+
 			var newData = innerData.Clone();
+			newData.GridType = gridType;
 			newData.Class = classification;
-			newData.GridType = gridType ?? modData.GetOrCreate<MapGrid>().Type;
 
 			if (yaml.TryGetValue("MapFormat", out var temp))
 			{
@@ -388,7 +410,7 @@ namespace OpenRA
 				newData.Title = temp.Value;
 
 			if (yaml.TryGetValue("Categories", out temp))
-				newData.Categories = FieldLoader.GetValue<ImmutableArray<string>>("Categories", temp.Value);
+				newData.Categories = FieldLoader.GetValue<string[]>("Categories", temp.Value);
 
 			if (yaml.TryGetValue("Tileset", out temp))
 				newData.TileSet = temp.Value;
@@ -409,7 +431,7 @@ namespace OpenRA
 			if (yaml.TryGetValue("MapFormat", out temp))
 				newData.MapFormat = FieldLoader.GetValue<int>("MapFormat", temp.Value);
 
-			newData.Status = modData.Manifest.MapCompatibility.Contains(requiresMod) ?
+			newData.Status = mapCompatibility == null || mapCompatibility.Contains(requiresMod) ?
 				MapStatus.Available : MapStatus.Unavailable;
 
 			try
@@ -420,18 +442,18 @@ namespace OpenRA
 					var spawns = new List<CPos>();
 					foreach (var kv in actorDefinitions.Nodes.Where(d => d.Value.Value == "mpspawn"))
 					{
-						var s = new ActorReference(kv.Value.Value, kv.Value);
+						var s = new ActorReference(kv.Value.Value, kv.Value.ToDictionary());
 						spawns.Add(s.Get<LocationInit>().Value);
 					}
 
-					newData.SpawnPoints = spawns.ToImmutableArray();
+					newData.SpawnPoints = spawns.ToArray();
 				}
 				else
-					newData.SpawnPoints = [];
+					newData.SpawnPoints = Array.Empty<CPos>();
 			}
 			catch (Exception)
 			{
-				newData.SpawnPoints = [];
+				newData.SpawnPoints = Array.Empty<CPos>();
 				newData.Status = MapStatus.Unavailable;
 			}
 
@@ -455,122 +477,31 @@ namespace OpenRA
 				using (var dataStream = p.GetStream("map.png"))
 					newData.Preview = new Png(dataStream);
 
-			newData.ModifiedDate = p.Name != null ? File.GetLastWriteTime(p.Name) : DateTime.Now;
+			newData.ModifiedDate = File.GetLastWriteTime(p.Name);
 
 			// Assign the new data atomically
-			// Local maps have higher precedence than remote/generated maps,
-			// so should always replace their metadata
-			lock (syncRoot)
 			innerData = newData;
 		}
 
-		public void UpdateFromGenerationArgs(MapGenerationArgs args)
-		{
-			var newData = innerData.Clone();
-			newData.Class = MapClassification.Generated;
-			newData.Status = MapStatus.Generatable;
-			newData.Title = args.Title;
-			newData.Author = args.Author;
-			newData.TileSet = args.Tileset;
-			newData.GenerationArgs = args;
-			newData.MapFormat = Map.CurrentMapFormat;
-
-			try
-			{
-				var generator = modData.DefaultRules.Actors[SystemActors.EditorWorld]
-					.TraitInfos<IMapGeneratorInfo>()
-					.FirstOrDefault(info => info.Type == args.Generator);
-
-				if (generator == null)
-					throw new Exception($"Unknown map generator type {args.Generator}");
-
-				if (!generator.TryGenerateMetadata(modData, args, out var players, out var ruleDefinitions))
-					throw new Exception("Failed to generate map metadata");
-
-				newData.Players = players;
-				newData.PlayerCount = newData.Players.Players.Count(x => x.Value.Playable);
-				newData.SetCustomRules(modData, this, ruleDefinitions, null);
-
-				// Placeholder to satisfy server-side lint checks
-				newData.SpawnPoints = Exts.MakeArray(newData.PlayerCount, i => new CPos(i, i)).ToImmutableArray();
-			}
-			catch (Exception e)
-			{
-				Log.Write("debug", "Map generation failed with error:");
-				Log.Write("debug", e);
-
-				newData.Status = MapStatus.Unavailable;
-			}
-
-			lock (syncRoot)
-				innerData = newData;
-		}
-
-		public void Generate()
-		{
-			if (Class != MapClassification.Generated || Status != MapStatus.Generatable)
-				return;
-
-			lock (syncRoot)
-				innerData.Status = MapStatus.Generating;
-
-			Task.Run(() =>
-			{
-				try
-				{
-					var generator = modData.DefaultRules.Actors[SystemActors.EditorWorld]
-						.TraitInfos<IMapGeneratorInfo>()
-						.FirstOrDefault(info => info.Type == GenerationArgs.Generator);
-
-					if (generator == null)
-						throw new Exception($"Unknown map generator type {GenerationArgs.Generator}");
-
-					var map = generator.Generate(modData, GenerationArgs);
-
-					// Uid is generated when the map is saved
-					map.Save(new ZipFileLoader.ReadWriteZipFile());
-
-					if (map.Uid != GenerationArgs.Uid)
-						throw new InvalidOperationException("Map generation UID mismatch");
-
-					Game.RunAfterTick(() => UpdateFromMap(map.Package, MapClassification.Generated));
-				}
-				catch (Exception e)
-				{
-					Log.Write("debug", "Map generation failed with error:");
-					Log.Write("debug", e);
-
-					lock (syncRoot)
-						innerData.Status = MapStatus.Unavailable;
-				}
-			});
-		}
-
-		public void BeginRemoteSearch()
+		public void UpdateRemoteSearch(MapStatus status, MiniYaml yaml, string[] mapCompatibility, Action<MapPreview> parseMetadata = null)
 		{
 			var newData = innerData.Clone();
+			newData.Status = status;
 			newData.Class = MapClassification.Remote;
-			newData.Status = MapStatus.Searching;
 
-			// We may have been resolved to a local/generated map by another
-			// async task. Make sure we don't stomp over their state!
-			lock (syncRoot)
-				if (innerData.Class == MapClassification.Unknown || innerData.Class == MapClassification.Remote)
-					innerData = newData;
-		}
-
-		public void CompleteRemoteSearch(MiniYaml yaml, Action<MapPreview> parseMetadata = null)
-		{
-			var newData = innerData.Clone();
-			newData.Class = MapClassification.Remote;
-			newData.Status = MapStatus.Unavailable;
-
-			if (yaml != null)
+			if (status == MapStatus.DownloadAvailable)
 			{
 				try
 				{
 					var r = FieldLoader.Load<RemoteMapData>(yaml);
-					newData.Status = r.downloading ? MapStatus.DownloadAvailable : MapStatus.Unavailable;
+
+					// Map download has been disabled server side
+					if (!r.downloading)
+					{
+						newData.Status = MapStatus.Unavailable;
+						return;
+					}
+
 					newData.Title = r.title;
 					newData.Categories = r.categories;
 					newData.Author = r.author;
@@ -582,7 +513,7 @@ namespace OpenRA
 					var spawns = new CPos[r.spawnpoints.Length / 2];
 					for (var j = 0; j < r.spawnpoints.Length; j += 2)
 						spawns[j / 2] = new CPos(r.spawnpoints[j], r.spawnpoints[j + 1]);
-					newData.SpawnPoints = spawns.ToImmutableArray();
+					newData.SpawnPoints = spawns;
 					newData.GridType = r.map_grid_type;
 					if (cache.LoadPreviewImages)
 					{
@@ -610,37 +541,29 @@ namespace OpenRA
 					// Map is for a different mod: update its information so it can be displayed
 					// in the cross-mod server browser UI, but mark it as unavailable so it can't
 					// be selected in a server for the current mod.
-					if (!modData.Manifest.MapCompatibility.Contains(r.game_mod))
+					if (!mapCompatibility.Contains(r.game_mod))
 						newData.Status = MapStatus.Unavailable;
 				}
 				catch (Exception e)
 				{
 					Log.Write("debug", "Failed parsing mapserver response:");
 					Log.Write("debug", e);
-					newData.Status = MapStatus.Unavailable;
-				}
 				}
 
-			// We may have been resolved to a local/generated map by another
-			// async task. Make sure we don't stomp over their state!
-			MapClassification mapClassification;
-			lock (syncRoot)
-			{
-				mapClassification = innerData.Class;
-				if (mapClassification == MapClassification.Remote)
+				// Commit updated data before running the callbacks
 				innerData = newData;
-			}
 
-			if (mapClassification == MapClassification.Remote)
-			{
 				if (innerData.Preview != null)
 					cache.CacheMinimap(this);
 
 				parseMetadata?.Invoke(this);
 			}
+
+			// Update the status and class unconditionally
+			innerData = newData;
 		}
 
-		public void Install(string mapRepositoryUrl)
+		public void Install(string mapRepositoryUrl, Action onSuccess)
 		{
 			if ((Status != MapStatus.DownloadError && Status != MapStatus.DownloadAvailable) || !Game.Settings.Game.AllowDownloading)
 				return;
@@ -693,11 +616,14 @@ namespace OpenRA
 					mapInstallPackage.Update(mapFilename, fileStream.ToArray());
 					Log.Write("debug", $"Downloaded map to '{mapFilename}'");
 
-					var p = mapInstallPackage.OpenPackage(mapFilename, modData.ModFiles);
-					if (p == null)
+					var package = mapInstallPackage.OpenPackage(mapFilename, modData.ModFiles);
+					if (package == null)
 						innerData.Status = MapStatus.DownloadError;
 					else
-						UpdateFromMapWithoutOwningPackage(p, mapInstallPackage, MapClassification.User, GridType);
+					{
+						UpdateFromMap(package, mapInstallPackage, MapClassification.User, null, GridType, null);
+						Game.RunAfterTick(onSuccess);
+					}
 				}
 				catch (Exception e)
 				{
@@ -710,31 +636,34 @@ namespace OpenRA
 
 		public void Invalidate()
 		{
-			lock (syncRoot)
-			{
-				innerData.Class = MapClassification.Unknown;
 			innerData.Status = MapStatus.Unavailable;
 		}
-		}
 
 		public void Dispose()
 		{
-			package?.Dispose();
+			DisposePackage();
+		}
+
+		public void DisposePackage()
+		{
+			if (package != null)
+			{
+				package.Dispose();
 				package = null;
 			}
+		}
 
 		public void Delete()
 		{
 			Invalidate();
-			(parentPackage as IReadWritePackage)?.Delete(Path);
+			(parentPackage as IReadWritePackage)?.Delete(Package.Name);
 		}
 
 		Stream IReadOnlyFileSystem.Open(string filename)
 		{
 			// Explicit package paths never refer to a map
-			LoadPackage();
-			if (!filename.Contains('|') && package.Contains(filename))
-				return package.GetStream(filename);
+			if (!filename.Contains('|') && Package.Contains(filename))
+				return Package.GetStream(filename);
 
 			return modData.DefaultFileSystem.Open(filename);
 		}
@@ -750,8 +679,7 @@ namespace OpenRA
 			// Explicit package paths never refer to a map
 			if (!filename.Contains('|'))
 			{
-				LoadPackage();
-				s = package.GetStream(filename);
+				s = Package.GetStream(filename);
 				if (s != null)
 					return true;
 			}
@@ -762,8 +690,7 @@ namespace OpenRA
 		bool IReadOnlyFileSystem.Exists(string filename)
 		{
 			// Explicit package paths never refer to a map
-			LoadPackage();
-			if (!filename.Contains('|') && package.Contains(filename))
+			if (!filename.Contains('|') && Package.Contains(filename))
 				return true;
 
 			return modData.DefaultFileSystem.Exists(filename);

OpenRA.Game/Map/PlayerReference.cs

@@ -9,7 +9,7 @@
  */
 #endregion
 
-using System.Collections.Immutable;
+using System;
 using OpenRA.Primitives;
 
 namespace OpenRA
@@ -31,7 +31,7 @@ namespace OpenRA
 		public string Faction;
 
 		public bool LockColor = false;
-		public Color Color = Game.ModData.GetOrCreate<DefaultPlayer>().Color;
+		public Color Color = Game.ModData.Manifest.Get<DefaultPlayer>().Color;
 
 		/// <summary>
 		/// Sets the "Home" location, which can be used by traits and scripts to e.g. set the initial camera
@@ -54,8 +54,8 @@ namespace OpenRA
 		public bool LockHandicap = false;
 		public int Handicap = 0;
 
-		public ImmutableArray<string> Allies = [];
-		public ImmutableArray<string> Enemies = [];
+		public string[] Allies = Array.Empty<string>();
+		public string[] Enemies = Array.Empty<string>();
 
 		public PlayerReference() { }
 		public PlayerReference(MiniYaml my) { FieldLoader.Load(this, my); }

OpenRA.Game/Map/ProjectedCellLayer.cs

@@ -55,9 +55,14 @@ namespace OpenRA
 			return Bounds.Contains(uv.U, uv.V);
 		}
 
+		public int IndexOf(T value, int startIndex)
+		{
+			return Array.IndexOf(Entries, value, startIndex);
+		}
+
 		public void SetAll(T value)
 		{
-			Entries.AsSpan().Fill(value);
+			Array.Fill(Entries, value);
 		}
 	}
 }

OpenRA.Game/Map/TerrainInfo.cs

@@ -10,7 +10,6 @@
 #endregion
 
 using System.Collections.Generic;
-using System.Collections.Immutable;
 using OpenRA.FileSystem;
 using OpenRA.Primitives;
 using OpenRA.Support;
@@ -26,16 +25,14 @@ namespace OpenRA
 	public interface ITerrainInfo
 	{
 		string Id { get; }
-		string Name { get; }
-		Size TileSize { get; }
-		ImmutableArray<TerrainTypeInfo> TerrainTypes { get; }
+		TerrainTypeInfo[] TerrainTypes { get; }
 		TerrainTileInfo GetTerrainInfo(TerrainTile r);
 		bool TryGetTerrainInfo(TerrainTile r, out TerrainTileInfo info);
 		byte GetTerrainIndex(string type);
 		byte GetTerrainIndex(TerrainTile r);
 		TerrainTile DefaultTerrainTile { get; }
 
-		ImmutableArray<Color> HeightDebugColors { get; }
+		Color[] HeightDebugColors { get; }
 		IEnumerable<Color> RestrictedPlayerColors { get; }
 		float MinHeightColorBrightness { get; }
 		float MaxHeightColorBrightness { get; }
@@ -63,7 +60,7 @@ namespace OpenRA
 	{
 		public readonly string Type;
 		public readonly BitSet<TargetableType> TargetTypes;
-		public readonly ImmutableArray<string> AcceptsSmudgeType = [];
+		public readonly HashSet<string> AcceptsSmudgeType = new();
 		public readonly Color Color;
 		public readonly bool RestrictPlayerColor = false;
 

OpenRA.Game/Map/TileReference.cs

@@ -11,35 +11,32 @@
 
 namespace OpenRA
 {
-	public readonly struct TerrainTile(ushort type, byte index)
+	public readonly struct TerrainTile
 	{
-		public readonly ushort Type = type;
-		public readonly byte Index = index;
+		public readonly ushort Type;
+		public readonly byte Index;
+
+		public TerrainTile(ushort type, byte index)
+		{
+			Type = type;
+			Index = index;
+		}
 
 		public override int GetHashCode() { return Type.GetHashCode() ^ Index.GetHashCode(); }
 
 		public override string ToString() { return Type + "," + Index; }
-
-		public static bool TryParse(string s, out TerrainTile tt)
-		{
-			var split = s.Split(',');
-			if (split.Length == 2 &&
-				Exts.TryParseUshortInvariant(split[0], out var type) &&
-				Exts.TryParseByteInvariant(split[1], out var index))
-			{
-				tt = new TerrainTile(type, index);
-				return true;
 	}
 
-			tt = default;
-			return false;
-		}
-	}
-
-	public readonly struct ResourceTile(byte type, byte index)
+	public readonly struct ResourceTile
 	{
-		public readonly byte Type = type;
-		public readonly byte Index = index;
+		public readonly byte Type;
+		public readonly byte Index;
+
+		public ResourceTile(byte type, byte index)
+		{
+			Type = type;
+			Index = index;
+		}
 
 		public override int GetHashCode() { return Type.GetHashCode() ^ Index.GetHashCode(); }
 	}

OpenRA.Game/MiniYaml.cs

@@ -59,10 +59,16 @@ namespace OpenRA
 
 	public sealed class MiniYamlNode
 	{
-		public readonly struct SourceLocation(string name, int line)
+		public readonly struct SourceLocation
 		{
-			public readonly string Name = name;
-			public readonly int Line = line;
+			public readonly string Name;
+			public readonly int Line;
+
+			public SourceLocation(string name, int line)
+			{
+				Name = name;
+				Line = line;
+			}
 
 			public override string ToString() { return $"{Name}:{Line}"; }
 		}
@@ -93,7 +99,7 @@ namespace OpenRA
 		}
 
 		public MiniYamlNode(string k, string v, string c = null)
-			: this(k, new MiniYaml(v, []), c) { }
+			: this(k, new MiniYaml(v, Enumerable.Empty<MiniYamlNode>()), c) { }
 
 		public MiniYamlNode(string k, string v, IEnumerable<MiniYamlNode> n)
 			: this(k, new MiniYaml(v, n), null) { }
@@ -109,7 +115,7 @@ namespace OpenRA
 		const int SpacesPerLevel = 4;
 		static readonly Func<string, string> StringIdentity = s => s;
 		static readonly Func<MiniYaml, MiniYaml> MiniYamlIdentity = my => my;
-		static readonly Dictionary<string, MiniYamlNode> ConflictScratch = [];
+		static readonly Dictionary<string, MiniYamlNode> ConflictScratch = new();
 
 		public readonly string Value;
 		public readonly ImmutableArray<MiniYamlNode> Nodes;
@@ -190,22 +196,21 @@ namespace OpenRA
 		}
 
 		public MiniYaml(string value)
-			: this(value, []) { }
+			: this(value, Enumerable.Empty<MiniYamlNode>()) { }
 
 		public MiniYaml(string value, IEnumerable<MiniYamlNode> nodes)
 		{
 			Value = value;
-			Nodes = nodes.ToImmutableArray();
+			Nodes = ImmutableArray.CreateRange(nodes);
 		}
 
-		static IEnumerable<MiniYamlNode> FromLines(
-			IEnumerable<ReadOnlyMemory<char>> lines, string name, bool discardCommentsAndWhitespace, HashSet<string> stringPool)
+		static List<MiniYamlNode> FromLines(IEnumerable<ReadOnlyMemory<char>> lines, string name, bool discardCommentsAndWhitespace, HashSet<string> stringPool)
 		{
 			// YAML config often contains repeated strings for key, values, comments.
 			// Pool these strings so we only need one copy of each unique string.
 			// This saves on long-term memory usage as parsed values can often live a long time.
 			// A caller can also provide a pool as input, allowing de-duplication across multiple parses.
-			stringPool ??= [];
+			stringPool ??= new HashSet<string>();
 
 			var result = new List<List<MiniYamlNode>>
 			{
@@ -336,25 +341,18 @@ namespace OpenRA
 
 					parsedLines.Add((level, keyString, valueString, commentString, location));
 				}
-
-				foreach (var topLevelNode in result[0])
-					yield return topLevelNode;
-				result[0].Clear();
 			}
 
 			if (parsedLines.Count > 0)
-			{
 				BuildCompletedSubNode(0);
-				foreach (var topLevelNode in result[0])
-					yield return topLevelNode;
-				result[0].Clear();
-			}
+
+			return result[0];
 
 			void BuildCompletedSubNode(int level)
 			{
 				var lastLevel = parsedLines[^1].Level;
 				while (lastLevel >= result.Count)
-					result.Add([]);
+					result.Add(new List<MiniYamlNode>());
 
 				while (parsedLines.Count > 0 && parsedLines[^1].Level >= level)
 				{
@@ -383,30 +381,29 @@ namespace OpenRA
 			}
 		}
 
-		public static IEnumerable<MiniYamlNode> FromFile(string path, bool discardCommentsAndWhitespace = true, HashSet<string> stringPool = null)
+		public static List<MiniYamlNode> FromFile(string path, bool discardCommentsAndWhitespace = true, HashSet<string> stringPool = null)
 		{
 			return FromStream(File.OpenRead(path), path, discardCommentsAndWhitespace, stringPool);
 		}
 
-		public static IEnumerable<MiniYamlNode> FromStream(Stream s, string name, bool discardCommentsAndWhitespace = true, HashSet<string> stringPool = null)
+		public static List<MiniYamlNode> FromStream(Stream s, string name, bool discardCommentsAndWhitespace = true, HashSet<string> stringPool = null)
 		{
 			return FromLines(s.ReadAllLinesAsMemory(), name, discardCommentsAndWhitespace, stringPool);
 		}
 
-		public static IEnumerable<MiniYamlNode> FromString(string text, string name, bool discardCommentsAndWhitespace = true, HashSet<string> stringPool = null)
+		public static List<MiniYamlNode> FromString(string text, string name, bool discardCommentsAndWhitespace = true, HashSet<string> stringPool = null)
 		{
-			return FromLines(text.Split(["\r\n", "\n"], StringSplitOptions.None).Select(s => s.AsMemory()), name, discardCommentsAndWhitespace, stringPool);
+			return FromLines(text.Split(new[] { "\r\n", "\n" }, StringSplitOptions.None).Select(s => s.AsMemory()), name, discardCommentsAndWhitespace, stringPool);
 		}
 
-		public static List<MiniYamlNode> Merge(IEnumerable<IEnumerable<MiniYamlNode>> sources)
+		public static List<MiniYamlNode> Merge(IEnumerable<IReadOnlyCollection<MiniYamlNode>> sources)
 		{
 			var sourcesList = sources.ToList();
 			if (sourcesList.Count == 0)
-				return [];
+				return new List<MiniYamlNode>();
 
 			var tree = sourcesList
 				.Where(s => s != null)
-				.Select(s => s as IReadOnlyCollection<MiniYamlNode> ?? s.ToList())
 				.Select(MergeSelfPartial)
 				.Aggregate(MergePartial)
 				.Where(n => n.Key != null)
@@ -506,9 +503,6 @@ namespace OpenRA
 			var ret = new List<MiniYamlNode>(existingNodes.Count);
 			foreach (var n in existingNodes)
 			{
-				if (n.Key == null)
-					continue;
-
 				if (keys.Add(n.Key))
 					ret.Add(n);
 				else
@@ -523,60 +517,17 @@ namespace OpenRA
 			return ret;
 		}
 
-		static IReadOnlyList<MiniYamlNode> WeakResolveRemovals(IReadOnlyList<MiniYamlNode> nodes)
-		{
-			if (nodes == null || nodes.Count == 0)
-				return nodes;
-
-			List<MiniYamlNode> ret = null;
-			for (var i = 0; i < nodes.Count; i++)
-			{
-				var node = nodes[i];
-				if (node.Key == null)
-					continue;
-
-				if (node.Key.StartsWith('-'))
-				{
-					if (ret == null)
-					{
-						ret ??= new List<MiniYamlNode>(nodes.Count);
-						ret.AddRange(nodes.Take(i));
-					}
-
-					// Apply the removal node - but "weakly" - don't throw if there is no prior node to remove.
-					var removed = node.Key[1..];
-					ret.RemoveAll(r => r.Key == removed);
-				}
-				else
-				{
-					ret?.Add(node);
-				}
-			}
-
-			return ret ?? nodes;
-		}
-
 		static MiniYaml MergePartial(MiniYaml existingNodes, MiniYaml overrideNodes)
 		{
-			var resolvedExistingNodes = WeakResolveRemovals(existingNodes?.Nodes);
-			var resolvedOverrideNodes = WeakResolveRemovals(overrideNodes?.Nodes);
-
 			lock (ConflictScratch)
-			{
-				try
 			{
 				// PERF: Reuse ConflictScratch for all conflict checks to avoid allocations.
-					resolvedExistingNodes?.IntoDictionaryWithConflictLog(
+				existingNodes?.Nodes.IntoDictionaryWithConflictLog(
 					n => n.Key, n => n, "MiniYaml.Merge", ConflictScratch, k => k, n => $"{n.Key} (at {n.Location})");
-					resolvedOverrideNodes?.IntoDictionaryWithConflictLog(
+				overrideNodes?.Nodes.IntoDictionaryWithConflictLog(
 					n => n.Key, n => n, "MiniYaml.Merge", ConflictScratch, k => k, n => $"{n.Key} (at {n.Location})");
 				ConflictScratch.Clear();
 			}
-				catch (ArgumentException ex)
-				{
-					throw new YamlException(ex.Message);
-				}
-			}
 
 			if (existingNodes == null)
 				return overrideNodes;
@@ -605,9 +556,6 @@ namespace OpenRA
 
 			void MergeNode(MiniYamlNode node)
 			{
-				if (node.Key == null)
-					return;
-
 				// Append Removal nodes to the result.
 				// Therefore: we know the remainder of the method deals with a plain node.
 				if (node.Key.StartsWith('-'))
@@ -678,12 +626,12 @@ namespace OpenRA
 		{
 			if (mapRules != null && mapRules.Value != null)
 			{
-				var mapFiles = FieldLoader.GetValue<ImmutableArray<string>>("value", mapRules.Value);
-				files = files.Concat(mapFiles);
+				var mapFiles = FieldLoader.GetValue<string[]>("value", mapRules.Value);
+				files = files.Append(mapFiles);
 			}
 
 			var stringPool = new HashSet<string>(); // Reuse common strings in YAML
-			var yaml = files.Select(s => FromStream(fileSystem.Open(s), s, stringPool: stringPool));
+			IEnumerable<IReadOnlyCollection<MiniYamlNode>> yaml = files.Select(s => FromStream(fileSystem.Open(s), s, stringPool: stringPool));
 			if (mapRules != null && mapRules.Nodes.Length > 0)
 				yaml = yaml.Append(mapRules.Nodes);
 
@@ -748,7 +696,7 @@ namespace OpenRA
 		public MiniYamlBuilder(string value, List<MiniYamlNode> nodes)
 		{
 			Value = value;
-			Nodes = nodes == null ? [] : nodes.ConvertAll(x => new MiniYamlNodeBuilder(x));
+			Nodes = nodes == null ? new List<MiniYamlNodeBuilder>() : nodes.ConvertAll(x => new MiniYamlNodeBuilder(x));
 		}
 
 		public MiniYaml Build()
@@ -776,6 +724,7 @@ namespace OpenRA
 		}
 	}
 
+	[Serializable]
 	public class YamlException : Exception
 	{
 		public YamlException(string s)

OpenRA.Game/ModData.cs

@@ -10,22 +10,18 @@
 #endregion
 
 using System;
-using System.Collections.Frozen;
 using System.Collections.Generic;
 using System.Collections.ObjectModel;
 using System.IO;
 using System.Linq;
 using OpenRA.FileSystem;
 using OpenRA.Graphics;
-using OpenRA.Primitives;
 using OpenRA.Video;
 using OpenRA.Widgets;
 using FS = OpenRA.FileSystem.FileSystem;
 
 namespace OpenRA
 {
-	public interface IGlobalModData { }
-
 	public sealed class ModData : IDisposable
 	{
 		public readonly Manifest Manifest;
@@ -35,13 +31,14 @@ namespace OpenRA
 		public readonly IPackageLoader[] PackageLoaders;
 		public readonly ISoundLoader[] SoundLoaders;
 		public readonly ISpriteLoader[] SpriteLoaders;
+		public readonly ITerrainLoader TerrainLoader;
 		public readonly ISpriteSequenceLoader SpriteSequenceLoader;
 		public readonly IVideoLoader[] VideoLoaders;
 		public readonly HotkeyManager Hotkeys;
 		public readonly IFileSystemLoader FileSystemLoader;
-		public readonly FrozenDictionary<string, CursorSequence> Cursors;
 
 		public ILoadScreen LoadScreen { get; }
+		public CursorProvider CursorProvider { get; private set; }
 		public FS ModFiles;
 		public IReadOnlyFileSystem DefaultFileSystem => ModFiles;
 
@@ -51,11 +48,9 @@ namespace OpenRA
 		readonly Lazy<IReadOnlyDictionary<string, ITerrainInfo>> defaultTerrainInfo;
 		public IReadOnlyDictionary<string, ITerrainInfo> DefaultTerrainInfo => defaultTerrainInfo.Value;
 
-		readonly TypeDictionary modules = [];
-
 		public ModData(Manifest mod, InstalledMods mods, bool useLoadScreen = false)
 		{
-			Languages = [];
+			Languages = Array.Empty<string>();
 
 			// Take a local copy of the manifest
 			Manifest = new Manifest(mod.Id, mod.Package);
@@ -65,64 +60,53 @@ namespace OpenRA
 
 			FileSystemLoader = ObjectCreator.GetLoader<IFileSystemLoader>(Manifest.FileSystem.Value, "filesystem");
 			FieldLoader.Load(FileSystemLoader, Manifest.FileSystem);
-			FileSystemLoader.Mount(Manifest, ModFiles, ObjectCreator);
+			FileSystemLoader.Mount(ModFiles, ObjectCreator);
 			ModFiles.TrimExcess();
 
-			foreach (var kv in Manifest.GlobalModData)
-			{
-				var t = ObjectCreator.FindType(kv.Key);
-				if (t == null || !typeof(IGlobalModData).IsAssignableFrom(t))
-					throw new InvalidDataException($"`{kv.Key}` is not a valid mod manifest entry.");
+			Manifest.LoadCustomData(ObjectCreator);
 
-				IGlobalModData module;
-				var ctor = t.GetConstructor([typeof(MiniYaml)]);
-				if (ctor != null)
-				{
-					// Class has opted-in to DIY initialization
-					module = (IGlobalModData)ctor.Invoke([kv.Value]);
-				}
-				else
-				{
-					// Automatically load the child nodes using FieldLoader
-					module = ObjectCreator.CreateObject<IGlobalModData>(kv.Key);
-					FieldLoader.Load(module, kv.Value);
-				}
-
-				modules.Add(module);
-			}
-
-			FluentProvider.Initialize(Manifest, DefaultFileSystem);
+			FluentProvider.Initialize(this, DefaultFileSystem);
 
 			if (useLoadScreen)
 			{
 				LoadScreen = ObjectCreator.CreateObject<ILoadScreen>(Manifest.LoadScreen.Value);
-				LoadScreen.Init(Manifest, DefaultFileSystem);
+				LoadScreen.Init(this, Manifest.LoadScreen.ToDictionary(my => my.Value));
 				LoadScreen.Display();
 			}
 
-			WidgetLoader = new WidgetLoader(Manifest, DefaultFileSystem);
-			MapCache = new MapCache(Manifest, ModFiles);
+			WidgetLoader = new WidgetLoader(this);
+			MapCache = new MapCache(this);
 
 			SoundLoaders = ObjectCreator.GetLoaders<ISoundLoader>(Manifest.SoundFormats, "sound");
 			SpriteLoaders = ObjectCreator.GetLoaders<ISpriteLoader>(Manifest.SpriteFormats, "sprite");
 			VideoLoaders = ObjectCreator.GetLoaders<IVideoLoader>(Manifest.VideoFormats, "video");
-			SpriteSequenceLoader = ObjectCreator.GetLoader<ISpriteSequenceLoader>(Manifest.SpriteSequenceFormat, "sequence");
-			Hotkeys = new HotkeyManager(ModFiles, ObjectCreator, Manifest);
-			Cursors = ParseCursors(Manifest, DefaultFileSystem);
+
+			var terrainFormat = Manifest.Get<TerrainFormat>();
+			var terrainLoader = ObjectCreator.FindType(terrainFormat.Type + "Loader");
+			var terrainCtor = terrainLoader?.GetConstructor(new[] { typeof(ModData) });
+			if (terrainLoader == null || !terrainLoader.GetInterfaces().Contains(typeof(ITerrainLoader)) || terrainCtor == null)
+				throw new InvalidOperationException($"Unable to find a terrain loader for type '{terrainFormat.Type}'.");
+
+			TerrainLoader = (ITerrainLoader)terrainCtor.Invoke(new[] { this });
+
+			var sequenceFormat = Manifest.Get<SpriteSequenceFormat>();
+			var sequenceLoader = ObjectCreator.FindType(sequenceFormat.Type + "Loader");
+			var sequenceCtor = sequenceLoader?.GetConstructor(new[] { typeof(ModData) });
+			if (sequenceLoader == null || !sequenceLoader.GetInterfaces().Contains(typeof(ISpriteSequenceLoader)) || sequenceCtor == null)
+				throw new InvalidOperationException($"Unable to find a sequence loader for type '{sequenceFormat.Type}'.");
+
+			SpriteSequenceLoader = (ISpriteSequenceLoader)sequenceCtor.Invoke(new[] { this });
+
+			Hotkeys = new HotkeyManager(ModFiles, Game.Settings.Keys, Manifest);
 
 			defaultRules = Exts.Lazy(() => Ruleset.LoadDefaults(this));
 			defaultTerrainInfo = Exts.Lazy(() =>
 			{
-				var terrainType = ObjectCreator.FindType(Manifest.TerrainFormat + "Loader");
-				var terrainCtor = terrainType?.GetConstructor([typeof(ModData)]);
-				if (terrainType == null || !terrainType.GetInterfaces().Contains(typeof(ITerrainLoader)) || terrainCtor == null)
-					throw new InvalidOperationException($"Unable to find a terrain loader for type '{Manifest.TerrainFormat}'.");
-
 				var items = new Dictionary<string, ITerrainInfo>();
-				var terrainLoader = (ITerrainLoader)terrainCtor.Invoke([this]);
+
 				foreach (var file in Manifest.TileSets)
 				{
-					var t = terrainLoader.ParseTerrain(DefaultFileSystem, file);
+					var t = TerrainLoader.ParseTerrain(DefaultFileSystem, file);
 					items.Add(t.Id, t);
 				}
 
@@ -132,23 +116,6 @@ namespace OpenRA
 			initialThreadId = Environment.CurrentManagedThreadId;
 		}
 
-		static FrozenDictionary<string, CursorSequence> ParseCursors(Manifest manifest, IReadOnlyFileSystem fileSystem)
-		{
-			var stringPool = new HashSet<string>(); // Reuse common strings in YAML
-			var sequenceYaml = MiniYaml.Merge(manifest.Cursors.Select(
-				s => MiniYaml.FromStream(fileSystem.Open(s), s, stringPool: stringPool)));
-
-			var cursors = new Dictionary<string, CursorSequence>();
-			foreach (var node in sequenceYaml)
-				if (node.Key == "Cursors")
-					foreach (var fileNode in node.Value.Nodes)
-						foreach (var sequenceNode in fileNode.Value.Nodes)
-							cursors.Add(sequenceNode.Key, new CursorSequence(
-								sequenceNode.Key, fileNode.Key, fileNode.Value.Value, sequenceNode.Value));
-
-			return cursors.ToFrozenDictionary();
-		}
-
 		// HACK: Only update the loading screen if we're in the main thread.
 		readonly int initialThreadId;
 		internal void HandleLoadingProgress()
@@ -165,18 +132,26 @@ namespace OpenRA
 			// horribly when you use ModData in unexpected ways.
 			ChromeMetrics.Initialize(this);
 			ChromeProvider.Initialize(this);
-			Ui.Initialize(this);
-			FluentProvider.Initialize(Manifest, fileSystem);
+			FluentProvider.Initialize(this, fileSystem);
 
 			Game.Sound.Initialize(SoundLoaders, fileSystem);
+
+			CursorProvider = new CursorProvider(this);
 		}
 
 		public IEnumerable<string> Languages { get; }
 
-		public void PrepareMap(Map map)
+		public Map PrepareMap(string uid)
 		{
 			LoadScreen?.Display();
 
+			if (MapCache[uid].Status != MapStatus.Available)
+				throw new InvalidDataException($"Invalid map uid: {uid}");
+
+			Map map;
+			using (new Support.PerfTimer("Map"))
+				map = new Map(this, MapCache[uid].Package);
+
 			// Reinitialize all our assets
 			InitializeLoaders(map);
 			map.Sequences.LoadSprites();
@@ -185,37 +160,14 @@ namespace OpenRA
 			using (new Support.PerfTimer("Map.Music"))
 				foreach (var entry in map.Rules.Music)
 					entry.Value.Load(map);
+
+			return map;
 		}
 
-		public MiniYamlNode[][] GetRulesYaml()
+		public List<MiniYamlNode>[] GetRulesYaml()
 		{
 			var stringPool = new HashSet<string>(); // Reuse common strings in YAML
-			return Manifest.Rules.Select(s => MiniYaml.FromStream(DefaultFileSystem.Open(s), s, stringPool: stringPool).ToArray()).ToArray();
-		}
-
-		/// <summary>Load a cached IGlobalModData instance.</summary>
-		public T GetOrCreate<T>() where T : IGlobalModData
-		{
-			var module = modules.GetOrDefault<T>();
-
-			// Lazily create the default values if not explicitly defined.
-			if (module == null)
-			{
-				module = (T)ObjectCreator.CreateBasic(typeof(T));
-				modules.Add(module);
-			}
-
-			return module;
-		}
-
-		public T GetOrNull<T>() where T : IGlobalModData
-		{
-			return modules.GetOrDefault<T>();
-		}
-
-		public T GetSettings<T>() where T : SettingsModule
-		{
-			return Game.Settings.GetOrCreate<T>(ObjectCreator, Manifest.Id);
+			return Manifest.Rules.Select(s => MiniYaml.FromStream(DefaultFileSystem.Open(s), s, stringPool: stringPool)).ToArray();
 		}
 
 		public void Dispose()
@@ -225,18 +177,14 @@ namespace OpenRA
 
 			ObjectCreator?.Dispose();
 
-			foreach (var module in modules)
-			{
-				var disposableModule = module as IDisposable;
-				disposableModule?.Dispose();
-			}
+			Manifest.Dispose();
 		}
 	}
 
 	public interface ILoadScreen : IDisposable
 	{
 		/// <summary>Initializes the loadscreen with yaml data from the LoadScreen block in mod.yaml.</summary>
-		void Init(Manifest manifest, IReadOnlyFileSystem fileSystem);
+		void Init(ModData m, Dictionary<string, string> info);
 
 		/// <summary>Called at arbitrary times during mod load to rerender the loadscreen.</summary>
 		void Display();
@@ -245,7 +193,7 @@ namespace OpenRA
 		/// Called before loading the mod assets.
 		/// Returns false if mod loading should be aborted (e.g. switching to another mod instead).
 		/// </summary>
-		bool BeforeLoad(ModData modData);
+		bool BeforeLoad();
 
 		/// <summary>Called when the engine expects to connect to a server/replay or load the shellmap.</summary>
 		void StartGame(Arguments args);
@@ -253,6 +201,6 @@ namespace OpenRA
 
 	public interface IFileSystemLoader
 	{
-		void Mount(Manifest manifest, FS fileSystem, ObjectCreator objectCreator);
+		void Mount(FS fileSystem, ObjectCreator objectCreator);
 	}
 }

OpenRA.Game/Network/Connection.cs

@@ -42,9 +42,9 @@ namespace OpenRA.Network
 	public sealed class EchoConnection : IConnection
 	{
 		const int LocalClientId = 1;
-		readonly Queue<(int Frame, int SyncHash, ulong DefeatState)> sync = [];
-		readonly Queue<(int Frame, OrderPacket Orders)> orders = [];
-		readonly Queue<OrderPacket> immediateOrders = [];
+		readonly Queue<(int Frame, int SyncHash, ulong DefeatState)> sync = new();
+		readonly Queue<(int Frame, OrderPacket Orders)> orders = new();
+		readonly Queue<OrderPacket> immediateOrders = new();
 		bool disposed;
 
 		int IConnection.LocalClientId => LocalClientId;
@@ -52,7 +52,7 @@ namespace OpenRA.Network
 		void IConnection.StartGame()
 		{
 			// Inject an empty frame to fill the gap we are making by projecting forward orders
-			orders.Enqueue((0, new OrderPacket([])));
+			orders.Enqueue((0, new OrderPacket(Array.Empty<Order>())));
 		}
 
 		void IConnection.Send(int frame, IEnumerable<Order> o)
@@ -100,12 +100,12 @@ namespace OpenRA.Network
 	{
 		public readonly ConnectionTarget Target;
 		internal ReplayRecorder Recorder { get; private set; }
-		readonly Queue<(int Frame, int SyncHash, ulong DefeatState)> sentSync = [];
-		readonly Queue<(int Frame, int SyncHash, ulong DefeatState)> queuedSyncPackets = [];
+		readonly Queue<(int Frame, int SyncHash, ulong DefeatState)> sentSync = new();
+		readonly Queue<(int Frame, int SyncHash, ulong DefeatState)> queuedSyncPackets = new();
 
-		readonly Queue<(int Frame, OrderPacket Orders)> sentOrders = [];
-		readonly Queue<OrderPacket> sentImmediateOrders = [];
-		readonly ConcurrentQueue<(int FromClient, byte[] Data)> receivedPackets = [];
+		readonly Queue<(int Frame, OrderPacket Orders)> sentOrders = new();
+		readonly Queue<OrderPacket> sentImmediateOrders = new();
+		readonly ConcurrentQueue<(int FromClient, byte[] Data)> receivedPackets = new();
 		TcpClient tcp;
 		volatile ConnectionState connectionState = ConnectionState.Connecting;
 		volatile int clientId;

OpenRA.Game/Network/ConnectionTarget.cs

@@ -22,12 +22,12 @@ namespace OpenRA.Network
 
 		public ConnectionTarget()
 		{
-			endpoints = [new DnsEndPoint("invalid", 0)];
+			endpoints = new[] { new DnsEndPoint("invalid", 0) };
 		}
 
 		public ConnectionTarget(string host, int port)
 		{
-			endpoints = [new DnsEndPoint(host, port)];
+			endpoints = new[] { new DnsEndPoint(host, port) };
 		}
 
 		public ConnectionTarget(IEnumerable<DnsEndPoint> endpoints)
@@ -48,7 +48,7 @@ namespace OpenRA.Network
 				}
 				catch (Exception)
 				{
-					return [];
+					return Enumerable.Empty<IPEndPoint>();
 				}
 			}).ToList();
 		}

OpenRA.Game/Network/FluentMessage.cs

@@ -11,7 +11,6 @@
 
 using System;
 using System.Collections.Generic;
-using System.Collections.Immutable;
 using Linguini.Shared.Types.Bundle;
 
 namespace OpenRA.Network
@@ -56,16 +55,14 @@ namespace OpenRA.Network
 		public readonly string Key = string.Empty;
 
 		[FieldLoader.LoadUsing(nameof(LoadArguments))]
-		public readonly ImmutableArray<object> Arguments;
+		public readonly object[] Arguments;
 
 		static object LoadArguments(MiniYaml yaml)
 		{
+			var arguments = new List<object>();
 			var argumentsNode = yaml.NodeWithKeyOrDefault("Arguments");
-
-			if (argumentsNode == null)
-				return ImmutableArray<object>.Empty;
-
-			var arguments = new List<object>(argumentsNode.Value.Nodes.Length * 2);
+			if (argumentsNode != null)
+			{
 				foreach (var argumentNode in argumentsNode.Value.Nodes)
 				{
 					var argument = FieldLoader.Load<FluentArgument>(argumentNode.Value);
@@ -80,8 +77,9 @@ namespace OpenRA.Network
 					else
 						arguments.Add(argument.Value);
 				}
+			}
 
-			return arguments.ToImmutableArray();
+			return arguments.ToArray();
 		}
 
 		public FluentMessage(MiniYaml yaml)

OpenRA.Game/Network/GameSave.cs

@@ -86,23 +86,22 @@ namespace OpenRA.Network
 		// Loaded from file and updated during gameplay
 		public int LastOrdersFrame { get; private set; }
 		public int LastSyncFrame { get; private set; }
-		byte[] lastSyncPacket = [];
+		byte[] lastSyncPacket = Array.Empty<byte>();
 
 		// Loaded from file or set on game start
 		public Session.Global GlobalSettings { get; private set; }
 		public Dictionary<string, Session.Slot> Slots { get; private set; }
 		public Dictionary<string, SlotClient> SlotClients { get; private set; }
-		public Dictionary<int, MiniYaml> TraitData = [];
-		public MapGenerationArgs MapGenerationArgs;
+		public Dictionary<int, MiniYaml> TraitData = new();
 
 		// Set on game start
-		int[] clientsBySlotIndex = [];
+		int[] clientsBySlotIndex = Array.Empty<int>();
 		int firstBotSlotIndex = -1;
 
 		public GameSave()
 		{
 			LastOrdersFrame = -1;
-			Slots = [];
+			Slots = new Dictionary<string, Session.Slot>();
 		}
 
 		public GameSave(string filepath)
@@ -124,10 +123,10 @@ namespace OpenRA.Network
 				lastSyncPacket = rs.ReadBytes(Order.SyncHashOrderLength);
 
 				var globalSettings = MiniYaml.FromString(rs.ReadLengthPrefixedString(Encoding.UTF8, Connection.MaxOrderLength), $"{filepath}:globalSettings");
-				GlobalSettings = Session.Global.Deserialize(globalSettings.First().Value);
+				GlobalSettings = Session.Global.Deserialize(globalSettings[0].Value);
 
 				var slots = MiniYaml.FromString(rs.ReadLengthPrefixedString(Encoding.UTF8, Connection.MaxOrderLength), $"{filepath}:slots");
-				Slots = [];
+				Slots = new Dictionary<string, Session.Slot>();
 				foreach (var s in slots)
 				{
 					var slot = Session.Slot.Deserialize(s.Value);
@@ -135,17 +134,13 @@ namespace OpenRA.Network
 				}
 
 				var slotClients = MiniYaml.FromString(rs.ReadLengthPrefixedString(Encoding.UTF8, Connection.MaxOrderLength), $"{filepath}:slotClients");
-				SlotClients = [];
+				SlotClients = new Dictionary<string, SlotClient>();
 				foreach (var s in slotClients)
 				{
 					var slotClient = SlotClient.Deserialize(s.Value);
 					SlotClients.Add(slotClient.Slot, slotClient);
 				}
 
-				var mapGenerationArgs = rs.ReadLengthPrefixedString(Encoding.UTF8, Connection.MaxOrderLength);
-				if (!string.IsNullOrEmpty(mapGenerationArgs))
-					MapGenerationArgs = FieldLoader.Load<MapGenerationArgs>(new MiniYaml("", MiniYaml.FromString(mapGenerationArgs, $"{filepath}:mapGenerationArgs")));
-
 				if (rs.Position != traitDataOffset || rs.ReadInt32() != TraitDataMarker)
 					throw new InvalidDataException("Invalid orasav file");
 
@@ -160,9 +155,6 @@ namespace OpenRA.Network
 
 		public void StartGame(Session lobbyInfo, MapPreview map)
 		{
-			if (map.Class == MapClassification.Generated)
-				MapGenerationArgs = map.GenerationArgs;
-
 			// Game orders are mapped from a client index to the slot that they occupy
 			// Orders from spectators are ignored, which is not a problem in practice
 			// because all immediate orders are also ignored
@@ -174,8 +166,8 @@ namespace OpenRA.Network
 
 			// Perform a deep clone by round-tripping the data
 			GlobalSettings = Session.Global.Deserialize(lobbyInfo.GlobalSettings.Serialize().Value);
-			Slots = [];
-			SlotClients = [];
+			Slots = new Dictionary<string, Session.Slot>();
+			SlotClients = new Dictionary<string, SlotClient>();
 			foreach (var s in lobbyInfo.Slots)
 			{
 				Slots[s.Key] = Session.Slot.Deserialize(s.Value.Serialize().Value);
@@ -314,8 +306,6 @@ namespace OpenRA.Network
 					.ToList();
 				file.WriteLengthPrefixedString(Encoding.UTF8, slotClientNodes.WriteToString());
 
-				file.WriteLengthPrefixedString(Encoding.UTF8, MapGenerationArgs?.Serialize().WriteToString() ?? string.Empty);
-
 				var traitDataOffset = file.Length;
 				file.Write(TraitDataMarker);
 

OpenRA.Game/Network/GameServer.cs

@@ -10,9 +10,7 @@
 #endregion
 
 using System;
-using System.Collections.Frozen;
 using System.Collections.Generic;
-using System.Collections.Immutable;
 using System.Linq;
 using System.Text.RegularExpressions;
 using OpenRA.Primitives;
@@ -49,9 +47,8 @@ namespace OpenRA.Network
 
 	public class GameServer
 	{
-		static readonly ImmutableArray<string> SerializeFields =
-		[
-
+		static readonly string[] SerializeFields =
+		{
 			// Server information
 			"Name", "Address",
 
@@ -60,7 +57,7 @@ namespace OpenRA.Network
 
 			// Current server state
 			"Map", "State", "MaxPlayers", "Protected", "Authentication", "DisabledSpawnPoints"
-		];
+		};
 
 		public const int ProtocolVersion = 2;
 
@@ -133,10 +130,10 @@ namespace OpenRA.Network
 		public readonly bool IsJoinable = false;
 
 		[FieldLoader.LoadUsing(nameof(LoadClients))]
-		public readonly ImmutableArray<GameClient> Clients;
+		public readonly GameClient[] Clients;
 
 		/// <summary>The list of spawnpoints that are disabled for this game.</summary>
-		public readonly FrozenSet<int> DisabledSpawnPoints = FrozenSet<int>.Empty;
+		public readonly int[] DisabledSpawnPoints = Array.Empty<int>();
 
 		public string ModLabel => $"{ModTitle} ({Version})";
 
@@ -152,7 +149,7 @@ namespace OpenRA.Network
 						clients.Add(FieldLoader.Load<GameClient>(client.Value));
 			}
 
-			return clients.ToImmutableArray();
+			return clients.ToArray();
 		}
 
 		public GameServer(MiniYaml yaml)
@@ -229,9 +226,9 @@ namespace OpenRA.Network
 			ModWebsite = manifest.Metadata.Website;
 			ModIcon32 = manifest.Metadata.WebIcon32;
 			Protected = !string.IsNullOrEmpty(server.Settings.Password);
-			Authentication = server.Settings.RequireAuthentication || server.Settings.ProfileIDWhitelist.Count > 0;
-			Clients = server.LobbyInfo.Clients.Select(c => new GameClient(c)).ToImmutableArray();
-			DisabledSpawnPoints = server.LobbyInfo.DisabledSpawnPoints?.ToFrozenSet() ?? FrozenSet<int>.Empty;
+			Authentication = server.Settings.RequireAuthentication || server.Settings.ProfileIDWhitelist.Length > 0;
+			Clients = server.LobbyInfo.Clients.Select(c => new GameClient(c)).ToArray();
+			DisabledSpawnPoints = server.LobbyInfo.DisabledSpawnPoints?.ToArray() ?? Array.Empty<int>();
 		}
 
 		public string ToPOSTData(bool lanGame)

OpenRA.Game/Network/Order.cs

@@ -269,11 +269,6 @@ namespace OpenRA
 			return new Order(order, null, false) { IsImmediate = isImmediate, TargetString = targetString };
 		}
 
-		public static Order FromTargetString(string order, string targetString, bool isImmediate, uint extraData)
-		{
-			return new Order(order, null, false) { IsImmediate = isImmediate, TargetString = targetString, ExtraData = extraData };
-		}
-
 		public static Order FromGroupedOrder(Order grouped, Actor subject)
 		{
 			return new Order(

OpenRA.Game/Network/OrderIO.cs

@@ -78,7 +78,7 @@ namespace OpenRA.Network
 
 	public static class OrderIO
 	{
-		static readonly OrderPacket NoOrders = new([]);
+		static readonly OrderPacket NoOrders = new(Array.Empty<Order>());
 
 		public static byte[] SerializeSync((int Frame, int SyncHash, ulong DefeatState) data)
 		{

OpenRA.Game/Network/OrderManager.cs

@@ -10,7 +10,6 @@
 #endregion
 
 using System;
-using System.Collections.Frozen;
 using System.Collections.Generic;
 using System.IO;
 using System.Linq;
@@ -27,8 +26,8 @@ namespace OpenRA.Network
 		const string DesyncCompareLogs = "notification-desync-compare-logs";
 
 		readonly SyncReport syncReport;
-		readonly Dictionary<int, Queue<(int Frame, OrderPacket Orders)>> pendingOrders = [];
-		readonly Dictionary<int, (int SyncHash, ulong DefeatState)> syncForFrame = [];
+		readonly Dictionary<int, Queue<(int Frame, OrderPacket Orders)>> pendingOrders = new();
+		readonly Dictionary<int, (int SyncHash, ulong DefeatState)> syncForFrame = new();
 
 		public Session LobbyInfo = new();
 
@@ -41,7 +40,7 @@ namespace OpenRA.Network
 		public bool AuthenticationFailed = false;
 
 		// The default null means "no map restriction" while an empty set means "all maps restricted"
-		public FrozenSet<string> ServerMapPool = null;
+		public HashSet<string> ServerMapPool = null;
 
 		public int NetFrameNumber { get; private set; }
 		public int LocalFrameNumber;
@@ -54,11 +53,11 @@ namespace OpenRA.Network
 		internal int GameSaveLastFrame = -1;
 		internal int GameSaveLastSyncFrame = -1;
 
-		readonly List<Order> localOrders = [];
-		readonly List<Order> localImmediateOrders = [];
+		readonly List<Order> localOrders = new();
+		readonly List<Order> localImmediateOrders = new();
 
-		readonly List<ClientOrder> processClientOrders = [];
-		readonly List<int> processClientsToRemove = [];
+		readonly List<ClientOrder> processClientOrders = new();
+		readonly List<int> processClientsToRemove = new();
 
 		bool disposed;
 		bool generateSyncReport = false;

OpenRA.Game/Network/ReplayConnection.cs

@@ -24,8 +24,8 @@ namespace OpenRA.Network
 			public (int ClientId, byte[] Packet)[] Packets;
 		}
 
-		readonly Queue<Chunk> chunks = [];
-		readonly Queue<(int Frame, int SyncHash, ulong DefeatState)> sync = [];
+		readonly Queue<Chunk> chunks = new();
+		readonly Queue<(int Frame, int SyncHash, ulong DefeatState)> sync = new();
 		readonly int orderLatency;
 
 		public readonly int TickCount;
@@ -87,7 +87,7 @@ namespace OpenRA.Network
 				}
 			}
 
-			var gameSpeeds = Game.ModData.GetOrCreate<GameSpeeds>();
+			var gameSpeeds = Game.ModData.Manifest.Get<GameSpeeds>();
 			var gameSpeedName = LobbyInfo.GlobalSettings.OptionOrDefault("gamespeed", gameSpeeds.DefaultSpeed);
 			orderLatency = gameSpeeds.Speeds[gameSpeedName].OrderLatency;
 		}

OpenRA.Game/Network/Session.cs

@@ -20,12 +20,12 @@ namespace OpenRA.Network
 {
 	public class Session
 	{
-		public List<Client> Clients = [];
+		public List<Client> Clients = new();
 
 		// Keyed by the PlayerReference id that the slot corresponds to
-		public Dictionary<string, Slot> Slots = [];
+		public Dictionary<string, Slot> Slots = new();
 
-		public HashSet<int> DisabledSpawnPoints = [];
+		public HashSet<int> DisabledSpawnPoints = new();
 
 		public Global GlobalSettings = new();
 
@@ -213,16 +213,15 @@ namespace OpenRA.Network
 			public bool AllowSpectators = true;
 			public string GameUid;
 			public bool EnableSingleplayer;
-			public bool EnableMapGeneration;
-			public bool EnableGameSaves;
 			public bool EnableSyncReports;
 			public bool Dedicated;
+			public bool GameSavesEnabled;
 
 			// 120ms network frame interval for 40ms local tick
 			public int NetFrameInterval = 3;
 
 			[FieldLoader.Ignore]
-			public Dictionary<string, LobbyOptionState> LobbyOptions = [];
+			public Dictionary<string, LobbyOptionState> LobbyOptions = new();
 
 			public static Global Deserialize(MiniYaml data)
 			{
@@ -241,7 +240,7 @@ namespace OpenRA.Network
 				var data = new MiniYamlNode("GlobalSettings", FieldSaver.Save(this));
 				var options = LobbyOptions.Select(kv => new MiniYamlNode(kv.Key, FieldSaver.Save(kv.Value)));
 				data = data.WithValue(data.Value.WithNodesAppended(
-					[new MiniYamlNode("Options", new MiniYaml(null, options))]));
+					new[] { new MiniYamlNode("Options", new MiniYaml(null, options)) }));
 				return data;
 			}
 

OpenRA.Game/Network/SyncReport.cs

@@ -166,9 +166,9 @@ namespace OpenRA.Network
 			public int Frame;
 			public int SyncedRandom;
 			public int TotalCount;
-			public readonly List<TraitReport> Traits = [];
-			public readonly List<EffectReport> Effects = [];
-			public readonly List<OrderManager.ClientOrder> Orders = [];
+			public readonly List<TraitReport> Traits = new();
+			public readonly List<EffectReport> Effects = new();
+			public readonly List<OrderManager.ClientOrder> Orders = new();
 		}
 
 		struct TraitReport
@@ -202,10 +202,10 @@ namespace OpenRA.Network
 			{
 				const BindingFlags Flags = BindingFlags.Public | BindingFlags.NonPublic | BindingFlags.Instance;
 				var fields = type.GetFields(Flags)
-					.Where(fi => !fi.IsLiteral && !fi.IsStatic && fi.HasAttribute<VerifySyncAttribute>())
+					.Where(fi => !fi.IsLiteral && !fi.IsStatic && fi.HasAttribute<SyncAttribute>())
 					.ToList();
 				var properties = type.GetProperties(Flags)
-					.Where(pi => pi.HasAttribute<VerifySyncAttribute>())
+					.Where(pi => pi.HasAttribute<SyncAttribute>())
 					.ToList();
 
 				foreach (var prop in properties)
@@ -238,11 +238,11 @@ namespace OpenRA.Network
 						// PERF: If the member is a Boolean, we can also avoid the allocation caused by boxing it.
 						// Instead, we can just return the resulting strings directly.
 						var getBoolString = Expression.Condition(getMember, TrueString, FalseString);
-						return Expression.Lambda<Func<ISync, string>>(getBoolString, name, [SyncParam]).Compile();
+						return Expression.Lambda<Func<ISync, string>>(getBoolString, name, new[] { SyncParam }).Compile();
 					}
 
 					var boxedCopy = Expression.Convert(getMember, typeof(object));
-					return Expression.Lambda<Func<ISync, object>>(boxedCopy, name, [SyncParam]).Compile();
+					return Expression.Lambda<Func<ISync, object>>(boxedCopy, name, new[] { SyncParam }).Compile();
 				}
 
 				// For reference types, we have to call ToString right away to get a snapshot of the value. We cannot
@@ -266,13 +266,13 @@ namespace OpenRA.Network
 					// (ISync sync) => { var foo = ((TSync)sync).Foo; return foo == null ? null : foo.ToString(); }
 					var memberVariable = Expression.Variable(memberType, getMember.Member.Name);
 					var assignMemberVariable = Expression.Assign(memberVariable, getMember);
-					var member = Expression.Block([memberVariable], assignMemberVariable);
+					var member = Expression.Block(new[] { memberVariable }, assignMemberVariable);
 					getString = Expression.Call(member, toString);
 					var nullMember = Expression.Constant(null, memberType);
 					getString = Expression.Condition(Expression.Equal(member, nullMember), NullString, getString);
 				}
 
-				return Expression.Lambda<Func<ISync, string>>(getString, name, [SyncParam]).Compile();
+				return Expression.Lambda<Func<ISync, string>>(getString, name, new[] { SyncParam }).Compile();
 			}
 		}
 

OpenRA.Game/Network/UnitOrders.cs

@@ -9,7 +9,6 @@
  */
 #endregion
 
-using System.Collections.Frozen;
 using System.Collections.Generic;
 using System.Linq;
 using OpenRA.Server;
@@ -30,6 +29,9 @@ namespace OpenRA.Network
 		[FluentReference]
 		const string GameStarted = "notification-game-has-started";
 
+		[FluentReference]
+		const string GameSaved = "notification-game-saved";
+
 		[FluentReference("player")]
 		const string GamePaused = "notification-game-paused";
 
@@ -65,11 +67,11 @@ namespace OpenRA.Network
 					{
 						var message = new FluentMessage(node.Value);
 						if (message.Key == Joined)
-							TextNotificationsManager.AddPlayerJoinedLine(message.Key, message.Arguments.ToArray());
+							TextNotificationsManager.AddPlayerJoinedLine(message.Key, message.Arguments);
 						else if (message.Key == Left)
-							TextNotificationsManager.AddPlayerLeftLine(message.Key, message.Arguments.ToArray());
+							TextNotificationsManager.AddPlayerLeftLine(message.Key, message.Arguments);
 						else
-							TextNotificationsManager.AddSystemLine(message.Key, message.Arguments.ToArray());
+							TextNotificationsManager.AddSystemLine(message.Key, message.Arguments);
 					}
 
 					break;
@@ -181,7 +183,7 @@ namespace OpenRA.Network
 
 					if (!string.IsNullOrEmpty(order.TargetString))
 					{
-						var data = MiniYaml.FromString(order.TargetString, order.OrderString).ToList();
+						var data = MiniYaml.FromString(order.TargetString, order.OrderString);
 						var saveLastOrdersFrame = data.FirstOrDefault(n => n.Key == "SaveLastOrdersFrame");
 						if (saveLastOrdersFrame != null)
 							orderManager.GameSaveLastFrame =
@@ -201,7 +203,7 @@ namespace OpenRA.Network
 
 				case "SaveTraitData":
 				{
-					var data = MiniYaml.FromString(order.TargetString, order.OrderString).First();
+					var data = MiniYaml.FromString(order.TargetString, order.OrderString)[0];
 					var traitIndex = Exts.ParseInt32Invariant(data.Key);
 
 					world?.AddGameSaveTraitData(traitIndex, data.Value);
@@ -210,8 +212,11 @@ namespace OpenRA.Network
 				}
 
 				case "GameSaved":
+					if (!orderManager.World.IsReplay)
+						TextNotificationsManager.AddSystemLine(GameSaved);
+
 					foreach (var nsr in orderManager.World.WorldActor.TraitsImplementing<INotifyGameSaved>())
-						nsr.GameSaved(orderManager.World, order.ExtraData != 0);
+						nsr.GameSaved(orderManager.World);
 					break;
 
 				case "PauseGame":
@@ -380,21 +385,7 @@ namespace OpenRA.Network
 
 				case "SyncMapPool":
 				{
-					orderManager.ServerMapPool = FieldLoader.GetValue<FrozenSet<string>>("SyncMapPool", order.TargetString);
-					break;
-				}
-
-				case "GenerateMap":
-				{
-					var yaml = new MiniYaml(order.OrderString, MiniYaml.FromString(order.TargetString, order.OrderString));
-					var args = FieldLoader.Load<MapGenerationArgs>(yaml);
-					var preview = Game.ModData.MapCache[args.Uid];
-					if (preview.Status != MapStatus.Available && preview.Class != MapClassification.Generated)
-					{
-						preview.UpdateFromGenerationArgs(args);
-						preview.Generate();
-					}
-
+					orderManager.ServerMapPool = FieldLoader.GetValue<HashSet<string>>("SyncMapPool", order.TargetString);
 					break;
 				}
 

OpenRA.Game/ObjectCreator.cs

@@ -22,7 +22,7 @@ namespace OpenRA
 	{
 		// .NET does not support unloading assemblies, so mod libraries will leak across mod changes.
 		// This tracks the assemblies that have been loaded since game start so that we don't load multiple copies
-		static readonly Dictionary<string, Assembly> ResolvedAssemblies = [];
+		static readonly Dictionary<string, Assembly> ResolvedAssemblies = new();
 
 		readonly Cache<string, Type> typeCache;
 		readonly Cache<Type, ConstructorInfo> ctorCache;
@@ -55,9 +55,26 @@ namespace OpenRA
 
 			if (!ResolvedAssemblies.TryGetValue(hash, out var assembly))
 			{
+#if NET5_0_OR_GREATER
 				var loader = new Support.AssemblyLoader(resolvedPath);
 				assembly = loader.LoadDefaultAssembly();
 				ResolvedAssemblies.Add(hash, assembly);
+#else
+				assembly = Assembly.LoadFile(resolvedPath);
+				ResolvedAssemblies.Add(hash, assembly);
+
+				// Allow mods to use libraries.
+				var assemblyPath = Path.GetDirectoryName(resolvedPath);
+				if (assemblyPath != null)
+				{
+					foreach (var referencedAssembly in assembly.GetReferencedAssemblies())
+					{
+						var depedencyPath = Path.Combine(assemblyPath, referencedAssembly.Name + ".dll");
+						if (File.Exists(depedencyPath))
+							LoadAssembly(assemblyList, depedencyPath);
+					}
+				}
+#endif
 			}
 
 			assemblyList.Add(assembly);
@@ -77,7 +94,7 @@ namespace OpenRA
 
 		public T CreateObject<T>(string className)
 		{
-			return CreateObject<T>(className, []);
+			return CreateObject<T>(className, new Dictionary<string, object>());
 		}
 
 		public T CreateObject<T>(string className, Dictionary<string, object> args)
@@ -119,7 +136,7 @@ namespace OpenRA
 
 		public object CreateBasic(Type type)
 		{
-			return type.GetConstructor([]).Invoke([]);
+			return type.GetConstructor(Array.Empty<Type>()).Invoke(Array.Empty<object>());
 		}
 
 		public object CreateUsingArgs(ConstructorInfo ctor, Dictionary<string, object> args)

OpenRA.Game/OpenRA.Game.csproj

@@ -2,13 +2,18 @@
   <PropertyGroup>
     <RootNamespace>OpenRA</RootNamespace>
   </PropertyGroup>
-	<ItemGroup>
-		<PackageReference Include="Microsoft.Extensions.DependencyModel" Version="9.0.0" />
+  <ItemGroup Condition="'$(MSBuildRuntimeType)'!='Mono'">
+    <PackageReference Include="Microsoft.Extensions.DependencyModel" Version="6.0.2" />
     <PackageReference Include="System.Runtime.Loader" Version="4.3.0" />
+  </ItemGroup>
+  <ItemGroup Condition="'$(MSBuildRuntimeType)'=='Mono'">
+    <PackageReference Include="System.Collections.Immutable" Version="6.0.0" />
+  </ItemGroup>
+  <ItemGroup>
     <PackageReference Include="Linguini.Bundle" Version="0.8.1" />
     <PackageReference Include="OpenRA-Eluant" Version="1.0.22" />
     <PackageReference Include="Mono.NAT" Version="3.0.4" />
     <PackageReference Include="SharpZipLib" Version="1.4.2" />
-		<PackageReference Include="System.Threading.Channels" Version="9.0.0" />
+    <PackageReference Include="System.Threading.Channels" Version="6.0.0" />
   </ItemGroup>
 </Project>