Fix stub method descriptor override issue #13221

namelessssssssssss · 2023-10-17T09:35:12Z

Due to the design of StubServiceDescriptor, the StubMethodDescriptor with same method name will override each other in StubServiceDescriptor.

It will cause following problems:

The serialization or protocol depends on StubMethodDescriptor.retrunTypes and StubMethodDescriptor.returnClass can never get true return types. They can only get the wrong retrun types form the async StubMethodDescriptor, usually the CompletableFuture.class.
Issue Triple Dubbo dual protocol parameters are missing #13158
Issue 在使用基于 IDL 方式，客户端和服务端合并部署在一个应用中使用injvm ，报java.lang.ClassCastException #10910

Detail:
Currently, Dubbo3TripleGenerator will gererate 2 StubMethodDescriptor for each non-streaming method, one for sync call, the other for async call, and they share same method name.

//They have same name 
    private static final StubMethodDescriptor greetMethod = new StubMethodDescriptor("greet",
    org.apache.dubbo.samples.tri.grpc.GreeterRequest.class, org.apache.dubbo.samples.tri.grpc.GreeterReply.class, serviceDescriptor, MethodDescriptor.RpcType.UNARY,
    obj -> ((Message) obj).toByteArray(), obj -> ((Message) obj).toByteArray(), org.apache.dubbo.samples.tri.grpc.GreeterRequest::parseFrom,
    org.apache.dubbo.samples.tri.grpc.GreeterReply::parseFrom);

    private static final StubMethodDescriptor greetAsyncMethod = new StubMethodDescriptor("greet",
    org.apache.dubbo.samples.tri.grpc.GreeterRequest.class, java.util.concurrent.CompletableFuture.class, serviceDescriptor, MethodDescriptor.RpcType.UNARY,
    obj -> ((Message) obj).toByteArray(), obj -> ((Message) obj).toByteArray(), org.apache.dubbo.samples.tri.grpc.GreeterRequest::parseFrom,
    org.apache.dubbo.samples.tri.grpc.GreeterReply::parseFrom);

StubMethodDescriptor will add itself to StubServiceDescriptor when initialize:

  public StubMethodDescriptor(String methodName, Class<?> requestClass, Class<?> responseClass, StubServiceDescriptor serviceDescriptor, MethodDescriptor.RpcType rpcType, Pack requestPack, Pack responsePack, UnPack requestUnpack, UnPack responseUnpack) {
      //...
        serviceDescriptor.addMethod(this);
    }

And obviously only the last one will be stored into StubServiceDescriptor:

    public void addMethod(MethodDescriptor methodDescriptor) {
        //use method name as key
        this.methods.put( methodDescriptor.getMethodName(), Collections.singletonList(methodDescriptor));
        Map<String, MethodDescriptor> descMap = (Map)this.descToMethods.computeIfAbsent(methodDescriptor.getMethodName(), (k) -> {
            return new HashMap();
        });
        descMap.put(methodDescriptor.getParamDesc(), methodDescriptor);
    }

Why StubMethodDescriptor.returnClass is correct?
Some one provded a temporary fix in StubInvocationUtil:

But the returnTypes for RpcInvocation are still wrong.

Brief changelog

This PR make the async version StubMethodDescriptor declared before the sync version. It can make the sync version of StubMethodDescriptor override the async one in StubServiceDescriptor, and provides the ture retrun types when RpcInvocation initialize.
Then, for the async call, StubInvocationUtil will set returnTypes[0] to CompletableFuture.