Unary call throws "Cannot read properties of undefined (reading 'interceptors')"

[marcoslin]

Problem description

When making unary call and passing metadata as undefined, the library throws:

TypeError: Cannot read properties of undefined (reading 'interceptors')

This error doesn't happen when metadata is provided.

Reproduction steps

The client code when generated using ts-proto and configuring it with --ts_proto_opt=addGrpcMetadata=true, the following is generated:

  echo(request: EchoRequest, metadata?: Metadata): Observable<EchoResponse> {
    return this.client.echo(request, metadata);
  }

When code above is executed without passing a metadata, the TypeError is always thrown if the grpc call is of type UNARY.

Additional context

I managed to track the issue down to InterceptorArguments:

const interceptorArgs: InterceptorArguments = {
      clientInterceptors: this[INTERCEPTOR_SYMBOL],
      clientInterceptorProviders: this[INTERCEPTOR_PROVIDER_SYMBOL],
      callInterceptors: callProperties.callOptions.interceptors ?? [],
      callInterceptorProviders:
        callProperties.callOptions.interceptor_providers ?? [],
};

The setting of callInterceptors assume that callProperties.callOptions is never undefined. The fix could be made at checkOptionalUnaryResponseArguments L:214:

return { metadata: new Metadata(), options: arg1 || {}, callback: arg2 };

Maybe worth to check also fix L:226:

return { metadata: arg1, options: arg2 || {}, callback: arg3 };

[murgatroid99]

You are required to pass a callback when calling a unary method. The error messaging for that could be better.