[Net6] UpdateEngine codegen broken on Net6

[jasonswearingen]

Release Type: Unofficial Net6 build. see #1126

Platform(s): Windows, Net6, VS2022

Describe the bug
I am trying the TopDownRPG sample using Net6 and it is crashing when trying to invoke what appears to be some code replaced by AssemblyProcessor
Stride.Engine\Updater\UpdateEngine.cs:line 510

 nextObject = ((UpdatableProperty)operation.Member).GetObject(currentPtr);
System.InvalidProgramException
  HResult=0x8013153A
  Message=Common Language Runtime detected an invalid program.
  Source=Stride.Engine
  StackTrace:
   at Stride.Updater.UpdatableProperty.GetObject(IntPtr obj) in C:\repos\_stride\stride\sources\engine\Stride.Engine\Updater\UpdatableProperty.cs:line 43
   at Stride.Updater.UpdateEngine.Run(Object target, CompiledUpdate compiledUpdate, IntPtr updateData, UpdateObjectData[] updateObjects) in C:\repos\_stride\stride\sources\engine\Stride.Engine\Updater\UpdateEngine.cs:line 510

just glancing but it seems this is some custom IL injected into binaries to do lower-level / unsafe code. I can't debug into or view the actual code that is crashing.

To Reproduce
Steps to reproduce the behavior:

1. run GameStudio using net6 build.
2. construct project from TopDownRPG sample
3. try to run sample

Expected behavior
no unhandled exception

Mitigation
You can catch the thrown exception but animations won't play.

[jasonswearingen]

further diagnosis of the problem, coppied from discord chat

---

can someone figure out what this IL code does?

stride/sources/engine/Stride.Engine/Updater/UpdatableProperty.cs

Lines 36 to 41 in 7e83629

	// Note: IL is injected by UpdateEngineProcessor
	ldarg obj
	ldarg.0
	ldfld native int class Stride.Updater.UpdatableProperty::Getter
	calli instance object()
	ret

it's IL that the AssemblyProcessor is supposed to inject into Stride.Engine UpdatableProperty.GetObject()

Here is the AssemblyProcessor code that actually emits it:

stride/sources/core/Stride.Core.AssemblyProcessor/UpdateEngineProcessor.IL.cs

Lines 176 to 180 in 7e83629

	// UpdatableProperty.GetObject
	var getObject = RewriteBody(declaringTypeForObjectMethods.Methods.First(x => x.Name == "GetObject"));
	getObject.Emit(OpCodes.Ldarg, getObject.Body.Method.Parameters[0]);
	EmitGetCode(getObject, assembly.MainModule.TypeSystem.Object);
	getObject.Emit(OpCodes.Ret);

I can't look at the actual IL emitted, because it's injected at runtime. 😦

I want to try rewriting that in C#, because the injected IL is crashing in net6:

System.InvalidProgramException
  HResult=0x8013153A
  Message=Common Language Runtime detected an invalid program.
  Source=Stride.Engine
  StackTrace:
   at Stride.Updater.UpdatableProperty.GetObject(IntPtr obj) in C:\repos\_stride\stride\sources\engine\Stride.Engine\Updater\UpdatableProperty.cs:line 43
   at Stride.Updater.UpdateEngine.Run(Object target, CompiledUpdate compiledUpdate, IntPtr updateData, UpdateObjectData[] updateObjects) in C:\repos\_stride\stride\sources\engine\Stride.Engine\Updater\UpdateEngine.cs:line 514

to me, it looks like it's pinning the input currentPtr parameter and returning it as an object. But I don't know if my conversion is correct. what I did is simply:

var handle = GCHandle.FromIntPtr(currentPtr);
nextObject = handle.Target;

which doesn't crash, but the nextObject is some invalid memory that can't be read. Later on some code using it fails with System.AccessViolationException HResult=0x80004003 Message=Attempted to read or write protected memory. This is often an indication that other memory is corrupt.

So, I wonder if my code is a "correct" conversion of the IL.

[jasonswearingen]

That's the extent I'm going to be able to investigate this issue. someone else needs to take over from here.

as it stands, animations will crash the engine due to this. You can catch the thrown exception but animations won't play.

[jasonswearingen]

This issue has been repro'd using the current Net5 version of Stride with a game project targeting Net6.

[xen2]

I think I could fix it (all unit tests are passing)
Please cherry-pick xen2@5e82e0c
(you might need to add my repo as a remote so that LFS can pick up binaries properly)

[jasonswearingen]

it fails when building the TopDownRPG.Windows project, but I think due to a merge from master that removed CompilerApp.exe

Severity	Code	Description	Project	File	Line	Suppression State
Error		Stride AssetCompiler could not be found (Command: "C:\Users\Jason\.nuget\packages\stride.core.assets.compilerapp\4.1.0.1-net6\buildTransitive\..\lib\net6.0-windows7.0\Stride.Core.Assets.CompilerApp.exe")	TopDownRPGNet6.Windows	C:\Users\Jason\.nuget\packages\stride.core.assets.compilerapp\4.1.0.1-net6\buildTransitive\Stride.Core.Assets.CompilerApp.targets	115	

In that folder is Stride.Core.Assets.CompilerApp.dll now.

How can this be fixed? I am pretty sure I merged that properly. But I only tested to make sure GameStudio ran when I did.

[jasonswearingen]

I can't repro this with [de0a0cb] so it is an interaction with it and net6.

[jasonswearingen]

I will need to rollback changes from [de0a0cb] as the build-time errors are in an assembly executed at build time. This is not debuggable and no error information is provided.

[jasonswearingen]

I figured out the bug(s). Some paths in the build system were not updated to net6-windows7.0 properly. With that fixed, @xen2 fix worked.