PredictionV2 Generic Types

[Danon5]

It would be nice to support generic types for the replicate and reconcile methods so that abstract template methods can simply be filled out in derived classes. The derived classes would not need to directly use Tick or PostTick, nor the attributes.

using FishNet.Object;
using FishNet.Object.Prediction;
using FishNet.Transporting;

public abstract class ExampleBaseClass<TReplicateData, TReconcileData> : NetworkBehaviour
    where TReplicateData : IReplicateData
    where TReconcileData : IReconcileData {
        
    // an abstract method would be called to generate the data in OnTick
    [ReplicateV2]
    private void Replicate(TReplicateData data, ReplicateState state = ReplicateState.Invalid, Channel channel = Channel.Unreliable) {
            // would call an abstract method to perform the logic
    }
        
    // an abstract method would be called to generate the data in OnPostTick
    [ReconcileV2]
    private void Reconcile(TReconcileData data, Channel channel = Channel.Unreliable) {
            // would call an abstract method to perform the logic
    }
}

Currently, a simple setup like the one shown above will generate the following unhandled error in the IL postprocessor:

Processing assembly Library/Bee/artifacts/1900b0aE.dag/MyProject.dll, with 129 defines and 239 references
processors: FishNet.CodeGenerating.ILCore.FishNetILPP, Unity.Jobs.CodeGen.JobsILPostProcessor, zzzUnity.Burst.CodeGen.BurstILPostProcessor
running FishNet.CodeGenerating.ILCore.FishNetILPP
FishNet.CodeGenerating.ILCore.FishNetILPP: ILPostProcessor has thrown an exception: System.NullReferenceException: Object reference not set to an instance of an object.
   at FishNet.CodeGenerating.Helping.Extension.TypeReferenceExtensionsOld.IsClassOrStruct(TypeReference typeRef, CodegenSession session)
   at FishNet.CodeGenerating.Processing.PredictionProcessor.HasParameterError(MethodDefinition methodDef, TypeDefinition typeDef, Boolean replicateMethod)
   at FishNet.CodeGenerating.Processing.PredictionProcessor.Process(TypeDefinition typeDef)
   at FishNet.CodeGenerating.Processing.NetworkBehaviourProcessor.ProcessLocal(TypeDefinition typeDef)
   at FishNet.CodeGenerating.ILCore.FishNetILPP.CreateNetworkBehaviours(CodegenSession session)
   at FishNet.CodeGenerating.ILCore.FishNetILPP.Process(ICompiledAssembly compiledAssembly)
   at Unity.ILPP.Runner.PostProcessingPipeline.PostProcessAssemblyAsync(PostProcessAssemblyRequest request, Action`2 progressSink)
PostProcessing failed: System.NullReferenceException: Object reference not set to an instance of an object.
   at FishNet.CodeGenerating.Helping.Extension.TypeReferenceExtensionsOld.IsClassOrStruct(TypeReference typeRef, CodegenSession session)
   at FishNet.CodeGenerating.Processing.PredictionProcessor.HasParameterError(MethodDefinition methodDef, TypeDefinition typeDef, Boolean replicateMethod)
   at FishNet.CodeGenerating.Processing.PredictionProcessor.Process(TypeDefinition typeDef)
   at FishNet.CodeGenerating.Processing.NetworkBehaviourProcessor.ProcessLocal(TypeDefinition typeDef)
   at FishNet.CodeGenerating.ILCore.FishNetILPP.CreateNetworkBehaviours(CodegenSession session)
   at FishNet.CodeGenerating.ILCore.FishNetILPP.Process(ICompiledAssembly compiledAssembly)
   at Unity.ILPP.Runner.PostProcessingPipeline.PostProcessAssemblyAsync(PostProcessAssemblyRequest request, Action`2 progressSink)
   at Unity.ILPP.Runner.PostProcessingService.PostProcessAssembly(PostProcessAssemblyRequest request, IServerStreamWriter`1 responseStream, ServerCallContext context)
Unhandled Exception: System.InvalidOperationException: Post processing failed
   at Unity.ILPP.Trigger.TriggerApp.<ProcessArgumentsAsync>d__1.MoveNext() + 0xf74
--- End of stack trace from previous location ---
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw() + 0x20
   at Unity.ILPP.Trigger.TriggerApp.<ProcessArgumentsAsync>d__1.MoveNext() + 0x1149
--- End of stack trace from previous location ---
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw() + 0x20
   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task) + 0xb6
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task) + 0x42
   at Unity.ILPP.Trigger.TriggerApp.<RunAsync>d__0.MoveNext() + 0xc7
--- End of stack trace from previous location ---
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw() + 0x20
   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task) + 0xb6
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task) + 0x42
   at Program.<<Main>$>d__0.MoveNext() + 0x1a3
--- End of stack trace from previous location ---
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw() + 0x20
   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task) + 0xb6
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task) + 0x42
   at Program.<Main>(String[]) + 0x20
   at Unity.ILPP.Trigger!<BaseAddress>+0x47849b

[bigatostudios]

@FirstGearGames

This would be pretty useful to enforce in-house rules about how networked code should be organized and written. For example:

• In order to utilize Unity's JobSystem correctly, you need to have a clear idea of the shape of your game loop.
• This implies that you don't want to have a bunch of logic split into a bunch of different objects. Instead you want systems and fine-grain control of your update loop.
• This is all achievable with the current FishNet stack and its not that complicated (I've got this up and running on a simple example project).
• But... to do it, there's some boilerplate that can be error prone.
• This feature would allow one to remove most of that boilerplate so things are less likely to break due to silly mistakes in boilerplate.

I've got ~3 projects looking to use FishNet for various things (a Fighting Game's Lobby and a couple of other experimental prototypes). This would be a great help for all these projects as it would really support my teams preferred coding-style.

(I'd be happy to discuss more about my use-cases and the projects themselves if you need further clarity)

[FirstGearGames]

This would very much require some rework in the codegen. I can see the uses of this change but it would be a significant amount of work which isn't on the table at the moment. Normally I'd keep something like this open if I could provide a reasonable turn-around time, but I really cannot so I'll be closing it out. Sorry.