Show internal name instead of crashing when buildable actor has no tooltip

But throw a lint error instead.

OpenRA.Mods.Common/Lint/CheckTooltips.cs

@@ -0,0 +1,35 @@
+#region Copyright & License Information
+/*
+ * Copyright 2007-2016 The OpenRA Developers (see AUTHORS)
+ * 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.Linq;
+using OpenRA.Mods.Common.Traits;
+using OpenRA.Traits;
+
+namespace OpenRA.Mods.Common.Lint
+{
+	class CheckTooltips : ILintRulesPass
+	{
+		public void Run(Action<string> emitError, Action<string> emitWarning, Ruleset rules)
+		{
+			foreach (var actorInfo in rules.Actors)
+			{
+				var buildable = actorInfo.Value.TraitInfoOrDefault<BuildableInfo>();
+				if (buildable == null)
+					continue;
+
+				var tooltip = actorInfo.Value.TraitInfos<TooltipInfo>().FirstOrDefault(Exts.IsTraitEnabled);
+				if (tooltip == null)
+					emitError("The following buildable actor has no (enabled) Tooltip: " + actorInfo.Key);
+			}
+		}
+	}
+}

OpenRA.Mods.Common/OpenRA.Mods.Common.csproj

@@ -176,6 +176,7 @@
     <Compile Include="Lint\CheckActorReferences.cs" />
     <Compile Include="Lint\CheckSyncAnnotations.cs" />
     <Compile Include="Lint\CheckTraitPrerequisites.cs" />
+    <Compile Include="Lint\CheckTooltips.cs" />
     <Compile Include="Lint\CheckDeathTypes.cs" />
     <Compile Include="Lint\CheckRangeLimit.cs" />
     <Compile Include="Lint\CheckVoiceReferences.cs" />

OpenRA.Mods.Common/Widgets/Logic/Ingame/ProductionTooltipLogic.cs

@@ -55,14 +55,15 @@ namespace OpenRA.Mods.Common.Widgets.Logic
 				if (actor == null || actor == lastActor)
 					return;
 
-				var tooltip = actor.TraitInfos<TooltipInfo>().First(Exts.IsTraitEnabled);
+				var tooltip = actor.TraitInfos<TooltipInfo>().FirstOrDefault(Exts.IsTraitEnabled);
+				var name = tooltip != null ? tooltip.Name : actor.Name;
 				var buildable = actor.TraitInfo<BuildableInfo>();
 				var cost = actor.TraitInfo<ValuedInfo>().Cost;
 
-				nameLabel.GetText = () => tooltip.Name;
+				nameLabel.GetText = () => name;
 
 				var hotkey = palette.TooltipIcon.Hotkey;
-				var nameWidth = font.Measure(tooltip.Name).X;
+				var nameWidth = font.Measure(name).X;
 				var hotkeyText = "({0})".F(hotkey.DisplayString());
 				var hotkeyWidth = hotkey.IsValid() ? font.Measure(hotkeyText).X + 2 * nameLabel.Bounds.X : 0;
 				hotkeyLabel.GetText = () => hotkeyText;
@@ -103,7 +104,7 @@ namespace OpenRA.Mods.Common.Widgets.Logic
 				timeLabel.Bounds.X = powerLabel.Bounds.X = costLabel.Bounds.X = timeIcon.Bounds.Right + iconMargin;
 				widget.Bounds.Width = leftWidth + rightWidth + 3 * nameLabel.Bounds.X + timeIcon.Bounds.Width + iconMargin;
 
-				var leftHeight = font.Measure(tooltip.Name).Y + requiresFont.Measure(requiresString).Y + descFont.Measure(descString).Y;
+				var leftHeight = font.Measure(name).Y + requiresFont.Measure(requiresString).Y + descFont.Measure(descString).Y;
 				var rightHeight = font.Measure(powerString).Y + font.Measure(timeString).Y + font.Measure(costString).Y;
 				widget.Bounds.Height = Math.Max(leftHeight, rightHeight) * 3 / 2 + 3 * nameLabel.Bounds.Y;