Throw early when Lua function parameters are null.

OpenRA.Game/Scripting/ScriptMemberWrapper.cs

@@ -50,7 +50,7 @@ namespace OpenRA.Scripting
 			try
 			{
 				if (!IsMethod)
-					throw new LuaException("Trying to invoke a ScriptMemberWrapper that isn't a method!");
+					throw new LuaException($"Trying to invoke a {nameof(ScriptMemberWrapper)} that isn't a method!");
 
 				var mi = (MethodInfo)Member;
 				var pi = mi.GetParameters();

OpenRA.Mods.Common/Scripting/Global/TriggerGlobal.cs

@@ -23,11 +23,11 @@ namespace OpenRA.Mods.Common.Scripting
 		public TriggerGlobal(ScriptContext context)
 			: base(context) { }
 
-		public static ScriptTriggers GetScriptTriggers(Actor a)
+		public static ScriptTriggers GetScriptTriggers(Actor actor)
 		{
-			var events = a.TraitOrDefault<ScriptTriggers>();
+			var events = actor.TraitOrDefault<ScriptTriggers>();
 			if (events == null)
-				throw new LuaException($"Actor '{a.Info.Name}' requires the ScriptTriggers trait before attaching a trigger");
+				throw new LuaException($"Actor '{actor.Info.Name}' requires the ScriptTriggers trait before attaching a trigger");
 
 			return events;
 		}
@@ -54,43 +54,61 @@ namespace OpenRA.Mods.Common.Scripting
 
 		[Desc("Call a function for each passenger when it enters a transport. " +
 			"The callback function will be called as func(Actor transport, Actor passenger).")]
-		public void OnPassengerEntered(Actor a, LuaFunction func)
+		public void OnPassengerEntered(Actor actor, LuaFunction func)
 		{
-			GetScriptTriggers(a).RegisterCallback(Trigger.OnPassengerEntered, func, Context);
+			if (actor == null)
+				throw new NullReferenceException(nameof(actor));
+
+			GetScriptTriggers(actor).RegisterCallback(Trigger.OnPassengerEntered, func, Context);
 		}
 
 		[Desc("Call a function for each passenger when it exits a transport. " +
 			"The callback function will be called as func(Actor transport, Actor passenger).")]
-		public void OnPassengerExited(Actor a, LuaFunction func)
+		public void OnPassengerExited(Actor actor, LuaFunction func)
 		{
-			GetScriptTriggers(a).RegisterCallback(Trigger.OnPassengerExited, func, Context);
+			if (actor == null)
+				throw new NullReferenceException(nameof(actor));
+
+			GetScriptTriggers(actor).RegisterCallback(Trigger.OnPassengerExited, func, Context);
 		}
 
 		[Desc("Call a function each tick that the actor is idle. " +
 			"The callback function will be called as func(Actor self).")]
-		public void OnIdle(Actor a, LuaFunction func)
+		public void OnIdle(Actor actor, LuaFunction func)
 		{
-			GetScriptTriggers(a).RegisterCallback(Trigger.OnIdle, func, Context);
+			if (actor == null)
+				throw new NullReferenceException(nameof(actor));
+
+			GetScriptTriggers(actor).RegisterCallback(Trigger.OnIdle, func, Context);
 		}
 
 		[Desc("Call a function when the actor is damaged. The callback " +
 			"function will be called as func(Actor self, Actor attacker, int damage).")]
-		public void OnDamaged(Actor a, LuaFunction func)
+		public void OnDamaged(Actor actor, LuaFunction func)
 		{
-			GetScriptTriggers(a).RegisterCallback(Trigger.OnDamaged, func, Context);
+			if (actor == null)
+				throw new NullReferenceException(nameof(actor));
+
+			GetScriptTriggers(actor).RegisterCallback(Trigger.OnDamaged, func, Context);
 		}
 
 		[Desc("Call a function when the actor is killed. The callback " +
 			"function will be called as func(Actor self, Actor killer).")]
-		public void OnKilled(Actor a, LuaFunction func)
+		public void OnKilled(Actor actor, LuaFunction func)
 		{
-			GetScriptTriggers(a).RegisterCallback(Trigger.OnKilled, func, Context);
+			if (actor == null)
+				throw new NullReferenceException(nameof(actor));
+
+			GetScriptTriggers(actor).RegisterCallback(Trigger.OnKilled, func, Context);
 		}
 
 		[Desc("Call a function when all of the actors in a group are killed. The callback " +
 			"function will be called as func().")]
 		public void OnAllKilled(Actor[] actors, LuaFunction func)
 		{
+			if (actors == null)
+				throw new NullReferenceException(nameof(actors));
+
 			var group = actors.ToList();
 			var f = (LuaFunction)func.CopyReference();
 			void OnMemberKilled(Actor m)
@@ -137,15 +155,21 @@ namespace OpenRA.Mods.Common.Scripting
 				}
 			}
 
+			if (actors == null)
+				throw new NullReferenceException(nameof(actors));
+
 			foreach (var a in actors)
 				GetScriptTriggers(a).OnKilledInternal += OnMemberKilled;
 		}
 
 		[Desc("Call a function when this actor produces another actor. " +
 			"The callback function will be called as func(Actor producer, Actor produced).")]
-		public void OnProduction(Actor a, LuaFunction func)
+		public void OnProduction(Actor actors, LuaFunction func)
 		{
-			GetScriptTriggers(a).RegisterCallback(Trigger.OnProduction, func, Context);
+			if (actors == null)
+				throw new NullReferenceException(nameof(actors));
+
+			GetScriptTriggers(actors).RegisterCallback(Trigger.OnProduction, func, Context);
 		}
 
 		[Desc("Call a function when any actor produces another actor. The callback " +
@@ -159,6 +183,9 @@ namespace OpenRA.Mods.Common.Scripting
 			"The callback function will be called as func(Player player).")]
 		public void OnPlayerWon(Player player, LuaFunction func)
 		{
+			if (player == null)
+				throw new NullReferenceException(nameof(player));
+
 			GetScriptTriggers(player.PlayerActor).RegisterCallback(Trigger.OnPlayerWon, func, Context);
 		}
 
@@ -166,6 +193,9 @@ namespace OpenRA.Mods.Common.Scripting
 			"The callback function will be called as func(Player player).")]
 		public void OnPlayerLost(Player player, LuaFunction func)
 		{
+			if (player == null)
+				throw new NullReferenceException(nameof(player));
+
 			GetScriptTriggers(player.PlayerActor).RegisterCallback(Trigger.OnPlayerLost, func, Context);
 		}
 
@@ -173,6 +203,9 @@ namespace OpenRA.Mods.Common.Scripting
 			"The callback function will be called as func(Player player, int objectiveID).")]
 		public void OnObjectiveAdded(Player player, LuaFunction func)
 		{
+			if (player == null)
+				throw new NullReferenceException(nameof(player));
+
 			GetScriptTriggers(player.PlayerActor).RegisterCallback(Trigger.OnObjectiveAdded, func, Context);
 		}
 
@@ -180,6 +213,9 @@ namespace OpenRA.Mods.Common.Scripting
 			"The callback function will be called as func(Player player, int objectiveID).")]
 		public void OnObjectiveCompleted(Player player, LuaFunction func)
 		{
+			if (player == null)
+				throw new NullReferenceException(nameof(player));
+
 			GetScriptTriggers(player.PlayerActor).RegisterCallback(Trigger.OnObjectiveCompleted, func, Context);
 		}
 
@@ -187,27 +223,39 @@ namespace OpenRA.Mods.Common.Scripting
 			"The callback function will be called as func(Player player, int objectiveID).")]
 		public void OnObjectiveFailed(Player player, LuaFunction func)
 		{
+			if (player == null)
+				throw new NullReferenceException(nameof(player));
+
 			GetScriptTriggers(player.PlayerActor).RegisterCallback(Trigger.OnObjectiveFailed, func, Context);
 		}
 
 		[Desc("Call a function when this actor is added to the world. " +
 			"The callback function will be called as func(Actor self).")]
-		public void OnAddedToWorld(Actor a, LuaFunction func)
+		public void OnAddedToWorld(Actor actor, LuaFunction func)
 		{
-			GetScriptTriggers(a).RegisterCallback(Trigger.OnAddedToWorld, func, Context);
+			if (actor == null)
+				throw new NullReferenceException(nameof(actor));
+
+			GetScriptTriggers(actor).RegisterCallback(Trigger.OnAddedToWorld, func, Context);
 		}
 
 		[Desc("Call a function when this actor is removed from the world. " +
 			"The callback function will be called as func(Actor self).")]
-		public void OnRemovedFromWorld(Actor a, LuaFunction func)
+		public void OnRemovedFromWorld(Actor actor, LuaFunction func)
 		{
-			GetScriptTriggers(a).RegisterCallback(Trigger.OnRemovedFromWorld, func, Context);
+			if (actor == null)
+				throw new NullReferenceException(nameof(actor));
+
+			GetScriptTriggers(actor).RegisterCallback(Trigger.OnRemovedFromWorld, func, Context);
 		}
 
 		[Desc("Call a function when all of the actors in a group have been removed from the world. " +
 			"The callback function will be called as func().")]
 		public void OnAllRemovedFromWorld(Actor[] actors, LuaFunction func)
 		{
+			if (actors == null)
+				throw new NullReferenceException(nameof(actors));
+
 			var group = actors.ToList();
 
 			var f = (LuaFunction)func.CopyReference();
@@ -256,14 +304,17 @@ namespace OpenRA.Mods.Common.Scripting
 
 		[Desc("Call a function when this actor is captured. The callback function " +
 			"will be called as func(Actor self, Actor captor, Player oldOwner, Player newOwner).")]
-		public void OnCapture(Actor a, LuaFunction func)
+		public void OnCapture(Actor actors, LuaFunction func)
 		{
-			GetScriptTriggers(a).RegisterCallback(Trigger.OnCapture, func, Context);
+			if (actors == null)
+				throw new NullReferenceException(nameof(actors));
+
+			GetScriptTriggers(actors).RegisterCallback(Trigger.OnCapture, func, Context);
 		}
 
 		[Desc("Call a function when this actor is killed or captured. " +
 			"The callback function will be called as func().")]
-		public void OnKilledOrCaptured(Actor a, LuaFunction func)
+		public void OnKilledOrCaptured(Actor actor, LuaFunction func)
 		{
 			var called = false;
 
@@ -286,14 +337,20 @@ namespace OpenRA.Mods.Common.Scripting
 				}
 			}
 
-			GetScriptTriggers(a).OnCapturedInternal += OnKilledOrCaptured;
+			if (actor == null)
-			GetScriptTriggers(a).OnKilledInternal += OnKilledOrCaptured;
+				throw new NullReferenceException(nameof(actor));
+
+			GetScriptTriggers(actor).OnCapturedInternal += OnKilledOrCaptured;
+			GetScriptTriggers(actor).OnKilledInternal += OnKilledOrCaptured;
 		}
 
 		[Desc("Call a function when all of the actors in a group have been killed or captured. " +
 			"The callback function will be called as func().")]
 		public void OnAllKilledOrCaptured(Actor[] actors, LuaFunction func)
 		{
+			if (actors == null)
+				throw new NullReferenceException(nameof(actors));
+
 			var group = actors.ToList();
 
 			var f = (LuaFunction)func.CopyReference();
@@ -443,17 +500,23 @@ namespace OpenRA.Mods.Common.Scripting
 
 		[Desc("Call a function when this actor is infiltrated. The callback function " +
 			"will be called as func(Actor self, Actor infiltrator).")]
-		public void OnInfiltrated(Actor a, LuaFunction func)
+		public void OnInfiltrated(Actor actor, LuaFunction func)
 		{
-			GetScriptTriggers(a).RegisterCallback(Trigger.OnInfiltrated, func, Context);
+			if (actor == null)
+				throw new NullReferenceException(nameof(actor));
+
+			GetScriptTriggers(actor).RegisterCallback(Trigger.OnInfiltrated, func, Context);
 		}
 
 		[Desc("Call a function when this actor is discovered by an enemy or a player with a Neutral stance. " +
 			"The callback function will be called as func(Actor discovered, Player discoverer). " +
 			"The player actor needs the 'EnemyWatcher' trait. The actors to discover need the 'AnnounceOnSeen' trait.")]
-		public void OnDiscovered(Actor a, LuaFunction func)
+		public void OnDiscovered(Actor actor, LuaFunction func)
 		{
-			GetScriptTriggers(a).RegisterCallback(Trigger.OnDiscovered, func, Context);
+			if (actor == null)
+				throw new NullReferenceException(nameof(actor));
+
+			GetScriptTriggers(actor).RegisterCallback(Trigger.OnDiscovered, func, Context);
 		}
 
 		[Desc("Call a function when this player is discovered by an enemy or neutral player. " +
@@ -461,14 +524,20 @@ namespace OpenRA.Mods.Common.Scripting
 			"The player actor needs the 'EnemyWatcher' trait. The actors to discover need the 'AnnounceOnSeen' trait.")]
 		public void OnPlayerDiscovered(Player discovered, LuaFunction func)
 		{
+			if (discovered == null)
+				throw new NullReferenceException(nameof(discovered));
+
 			GetScriptTriggers(discovered.PlayerActor).RegisterCallback(Trigger.OnPlayerDiscovered, func, Context);
 		}
 
 		[Desc("Call a function when this actor is sold. The callback function " +
 			"will be called as func(Actor self).")]
-		public void OnSold(Actor a, LuaFunction func)
+		public void OnSold(Actor actor, LuaFunction func)
 		{
-			GetScriptTriggers(a).RegisterCallback(Trigger.OnSold, func, Context);
+			if (actor == null)
+				throw new NullReferenceException(nameof(actor));
+
+			GetScriptTriggers(actor).RegisterCallback(Trigger.OnSold, func, Context);
 		}
 
 		[Desc("Call a function when the game timer expires. The callback function will be called as func().")]
@@ -480,19 +549,25 @@ namespace OpenRA.Mods.Common.Scripting
 		[Desc("Removes all triggers from this actor. " +
 			"Note that the removal will only take effect at the end of a tick, " +
 			"so you must not add new triggers at the same time that you are calling this function.")]
-		public void ClearAll(Actor a)
+		public void ClearAll(Actor actor)
 		{
-			GetScriptTriggers(a).ClearAll();
+			if (actor == null)
+				throw new NullReferenceException(nameof(actor));
+
+			GetScriptTriggers(actor).ClearAll();
 		}
 
 		[Desc("Removes the specified trigger from this actor. " +
 			"Note that the removal will only take effect at the end of a tick, " +
 			"so you must not add new triggers at the same time that you are calling this function.")]
-		public void Clear(Actor a, string triggerName)
+		public void Clear(Actor actor, string triggerName)
 		{
 			var trigger = (Trigger)Enum.Parse(typeof(Trigger), triggerName);
 
-			GetScriptTriggers(a).Clear(trigger);
+			if (actor == null)
+				throw new NullReferenceException(nameof(actor));
+
+			GetScriptTriggers(actor).Clear(trigger);
 		}
 	}
 }