Report proper errors instead of NREs during trait and weapon linting

[abcdefg30]

Inspired by #20080. Both Game.CreateObject and modData.ObjectCreator.FindType return null when given an unknown type. That leads to walls of errors like:

OpenRA.Utility(1,1): Error: Missing Type: AsdInfo
OpenRA.Utility(1,1): Error: Missing Type: LeaveSmudgesWarhead
OpenRA.Utility(1,1): Error: Missing Type: BulletsInfo
[...]
OpenRA.Utility(1,1): Error: OpenRA.Mods.Common.Lint.CheckUnknownTraitFields failed with exception: System.NullReferenceException: Object reference not set to an instance of an object.
   at OpenRA.Mods.Common.Lint.CheckUnknownTraitFields.CheckActors(IEnumerable`1 actors, Action`1 emitError, ModData modData) in \OpenRA\OpenRA.Mods.Common\Lint\CheckUnknownTraitFields.cs:line 77
   at OpenRA.Mods.Common.Lint.CheckUnknownTraitFields.OpenRA.Mods.Common.Lint.ILintPass.Run(Action`1 emitError, Action`1 emitWarning, ModData modData) in \OpenRA\OpenRA.Mods.Common\Lint\CheckUnknownTraitFields.cs:line 24
   at OpenRA.Mods.Common.UtilityCommands.CheckYaml.OpenRA.IUtilityCommand.Run(Utility utility, String[] args) in \OpenRA\OpenRA.Mods.Common\UtilityCommands\CheckYaml.cs:line 72
[...]
OpenRA.Utility(1,1): Error: Failed with exception: System.AggregateException: One or more errors occurred. (Object reference not set to an instance of an object.)
 ---> System.NullReferenceException: Object reference not set to an instance of an object.
   at OpenRA.FieldLoader.Load(Object self, MiniYaml my) in \OpenRA\OpenRA.Game\FieldLoader.cs:line 533
   at OpenRA.GameRules.WeaponInfo.LoadProjectile(MiniYaml yaml) in \OpenRA\OpenRA.Game\GameRules\WeaponInfo.cs:line 143
   at OpenRA.FieldLoader.Load(Object self, MiniYaml my) in \OpenRA\OpenRA.Game\FieldLoader.cs:line 547
   at OpenRA.GameRules.WeaponInfo..ctor(MiniYaml content) in \OpenRA\OpenRA.Game\GameRules\WeaponInfo.cs:line 135
   at OpenRA.Ruleset.<>c.<LoadDefaults>b__12_3(MiniYamlNode k) in \OpenRA\OpenRA.Game\GameRules\Ruleset.cs:line 134
   at OpenRA.Exts.ToDictionaryWithConflictLog[TSource,TKey,TElement](IEnumerable`1 source, Func`2 keySelector, Func`2 elementSelector, String debugName, Func`2 logKey, Func`2 logValue) in \OpenRA\OpenRA.Game\Exts.cs:line 415
   at OpenRA.Ruleset.MergeOrDefault[T](String name, IReadOnlyFileSystem fileSystem, IEnumerable`1 files, MiniYaml additional, IReadOnlyDictionary`2 defaults, Func`2 makeObject, Func`2 filterNode) in \OpenRA\OpenRA.Game\GameRules\Ruleset.cs:line 118
   at OpenRA.Ruleset.<>c__DisplayClass12_0.<LoadDefaults>b__0() in \OpenRA\OpenRA.Game\GameRules\Ruleset.cs:line 133
   at System.Threading.Tasks.Task.InnerInvoke()
   at System.Threading.Tasks.Task.<>c.<.cctor>b__272_0(Object obj)
   at System.Threading.ExecutionContext.RunFromThreadPoolDispatchLoop(Thread threadPoolThread, ExecutionContext executionContext, ContextCallback callback, Object state)
--- End of stack trace from previous location ---
   at System.Threading.ExecutionContext.RunFromThreadPoolDispatchLoop(Thread threadPoolThread, ExecutionContext executionContext, ContextCallback callback, Object state)
   at System.Threading.Tasks.Task.ExecuteWithThreadLocal(Task& currentTaskSlot, Thread threadPoolThread)
   --- End of inner exception stack trace ---
   at System.Threading.Tasks.Task.ThrowIfExceptional(Boolean includeTaskCanceledExceptions)
   at System.Threading.Tasks.Task.Wait(Int32 millisecondsTimeout, CancellationToken cancellationToken)
   at System.Threading.Tasks.Task.Wait(Int32 millisecondsTimeout)
   at OpenRA.Ruleset.LoadDefaults(ModData modData) in \OpenRA\OpenRA.Game\GameRules\Ruleset.cs:line 160
   at OpenRA.ModData.<.ctor>b__32_2() in \OpenRA\OpenRA.Game\ModData.cs:line 110
   at System.Lazy`1.ViaFactory(LazyThreadSafetyMode mode)
   at System.Lazy`1.ExecutionAndPublication(LazyHelper executionAndPublication, Boolean useDefaultConstructor)
   at System.Lazy`1.CreateValue()
   at System.Lazy`1.get_Value()
   at OpenRA.ModData.get_DefaultRules() in \OpenRA\OpenRA.Game\ModData.cs:line 46
   at OpenRA.Mods.Common.UtilityCommands.CheckYaml.OpenRA.IUtilityCommand.Run(Utility utility, String[] args) in \OpenRA\OpenRA.Mods.Common\UtilityCommands\CheckYaml.cs:line 64
[...]
OpenRA.Utility(1,1): Error: Failed with exception: System.AggregateException: One or more errors occurred. (Object reference not set to an instance of an object.)
 ---> System.NullReferenceException: Object reference not set to an instance of an object.
   at OpenRA.FieldLoader.Load(Object self, MiniYaml my) in \OpenRA\OpenRA.Game\FieldLoader.cs:line 533
   at OpenRA.GameRules.WeaponInfo.LoadWarheads(MiniYaml yaml) in \OpenRA\OpenRA.Game\GameRules\WeaponInfo.cs:line 153
   at OpenRA.FieldLoader.Load(Object self, MiniYaml my) in \OpenRA\OpenRA.Game\FieldLoader.cs:line 547
   at OpenRA.GameRules.WeaponInfo..ctor(MiniYaml content) in \OpenRA\OpenRA.Game\GameRules\WeaponInfo.cs:line 135
   at OpenRA.Ruleset.<>c.<LoadDefaults>b__12_3(MiniYamlNode k) in \OpenRA\OpenRA.Game\GameRules\Ruleset.cs:line 134
   at OpenRA.Exts.ToDictionaryWithConflictLog[TSource,TKey,TElement](IEnumerable`1 source, Func`2 keySelector, Func`2 elementSelector, String debugName, Func`2 logKey, Func`2 logValue) in \OpenRA\OpenRA.Game\Exts.cs:line 415
   at OpenRA.Ruleset.MergeOrDefault[T](String name, IReadOnlyFileSystem fileSystem, IEnumerable`1 files, MiniYaml additional, IReadOnlyDictionary`2 defaults, Func`2 makeObject, Func`2 filterNode) in \OpenRA\OpenRA.Game\GameRules\Ruleset.cs:line 118
   at OpenRA.Ruleset.<>c__DisplayClass12_0.<LoadDefaults>b__0() in \OpenRA\OpenRA.Game\GameRules\Ruleset.cs:line 133
   at System.Threading.Tasks.Task.InnerInvoke()
   at System.Threading.Tasks.Task.<>c.<.cctor>b__272_0(Object obj)
   at System.Threading.ExecutionContext.RunFromThreadPoolDispatchLoop(Thread threadPoolThread, ExecutionContext executionContext, ContextCallback callback, Object state)
--- End of stack trace from previous location ---
   at System.Threading.ExecutionContext.RunFromThreadPoolDispatchLoop(Thread threadPoolThread, ExecutionContext executionContext, ContextCallback callback, Object state)
   at System.Threading.Tasks.Task.ExecuteWithThreadLocal(Task& currentTaskSlot, Thread threadPoolThread)
   --- End of inner exception stack trace ---
   at System.Threading.Tasks.Task.ThrowIfExceptional(Boolean includeTaskCanceledExceptions)
   at System.Threading.Tasks.Task.Wait(Int32 millisecondsTimeout, CancellationToken cancellationToken)
   at System.Threading.Tasks.Task.Wait(Int32 millisecondsTimeout)
   at OpenRA.Ruleset.LoadDefaults(ModData modData) in \OpenRA\OpenRA.Game\GameRules\Ruleset.cs:line 160
   at OpenRA.ModData.<.ctor>b__32_2() in \OpenRA\OpenRA.Game\ModData.cs:line 110
   at System.Lazy`1.ViaFactory(LazyThreadSafetyMode mode)
   at System.Lazy`1.ExecutionAndPublication(LazyHelper executionAndPublication, Boolean useDefaultConstructor)
   at System.Lazy`1.CreateValue()
   at System.Lazy`1.get_Value()
   at OpenRA.ModData.get_DefaultRules() in \OpenRA\OpenRA.Game\ModData.cs:line 46
   at OpenRA.Mods.Common.UtilityCommands.CheckYaml.OpenRA.IUtilityCommand.Run(Utility utility, String[] args) in \OpenRA\OpenRA.Mods.Common\UtilityCommands\CheckYaml.cs:line 64

Now just the location is provided without a huge stacktrace (since we don't crash in the first place):

Testing mod: Red Alert
OpenRA.Utility(1,1): Error: Missing Type: AsdInfo
OpenRA.Utility(1,1): Error: Missing Type: LeaveSmudgesWarhead
OpenRA.Utility(1,1): Error: Missing Type: BulletsInfo
[...]
OpenRA.Utility(1,1): Error: ra|rules/infantry.yaml:70 defines unknown trait `Asd`.
OpenRA.Utility(1,1): Error: ra|weapons/ballistics.yaml:20 defines unknown warhead `LeaveSmudges`.
OpenRA.Utility(1,1): Error: ra|weapons/ballistics.yaml:38 defines unknown projectile `Bullets`.
[...]

Testcases included as extra commit.

[penev92]

👍

[pchote]

IMO its a bit odd that most cases generate "Error: Missing Type" instead of the custom messages, but this is still an improvement over the existing behaviour.

Please remove testcase and merge.

[abcdefg30]

IMO its a bit odd that most cases generate "Error: Missing Type" instead of the custom messages, but this is still an improvement over the existing behaviour.

That is generated by

OpenRA/OpenRA.Mods.Common/UtilityCommands/CheckYaml.cs

Line 55 in 6a31b1f

ObjectCreator.MissingTypeAction = s => EmitError($"Missing Type: {s}");

[pchote]

https://github.com/OpenRA/OpenRA/wiki/Changelog-(bleed)/_compare/638c27d3835f3fcb02f93afd966e921de253d308