egametang/ET · error · Exception

service discovery response type mismatch, request: {requestN

Error message

service discovery response type mismatch, request: {requestName}, actual: {rawResponse?.GetType().Name}

What it means

Thrown at line 628 in ForwardToDiscoveryByFailoverCore: the master returned a response whose runtime type is not the expected T (the strongly-typed response the caller requested). The raw response is disposed and the call aborts. This indicates a contract/serialization mismatch between what the caller expects and what the master (or the routing layer) actually returned.

Source

Thrown at Packages/cn.etetet.servicediscovery/Scripts/Hotfix/Server/ServiceDiscoveryAgentSystem.cs:628

                    }

                    continue;
                }

                ActorId targetActorId = self.ServiceDiscoveryActorId;
                try
                {
                    IResponse rawResponse = await self.MessageSender.Call(targetActorId, request);
                    self = selfRef;
                    if (self == null)
                    {
                        throw new Exception("service discovery agent disposed");
                    }

                    if (rawResponse is not T response)
                    {
                        (rawResponse as MessageObject)?.Dispose();
                        throw new Exception(
                            $"service discovery response type mismatch, request: {requestName}, actual: {rawResponse?.GetType().Name}");
                    }

                    if (response.Error != ErrorCode.ERR_Success)
                    {
                        int error = response.Error;
                        string message = response.Message;
                        if (response is MessageObject messageObject)
                        {
                            messageObject.Dispose();
                        }
                        throw new RpcException(error,
                            $"service discovery response error, request: {requestName}, error: {error}, message: {message}");
                    }

                    return response;
                }
                catch (Exception e)

View on GitHub (pinned to 5cab01f7a8)

Solutions

1. Ensure all processes run the same version of the service-discovery message assembly (rebuild and redeploy together).
2. Confirm the request type maps to the expected response type T at the call site.
3. Regenerate protocol/proto definitions and verify the response class is identical across client and master.

Example fix

// before: T does not match the request's actual response type
var resp = await agent.ForwardToDiscoveryByFailover<WrongResponse>(req, name);

// after: use the response type paired with the request
var resp = await agent.ForwardToDiscoveryByFailover<ServiceRegisterResponse>(req, name);

// Ensure the response type matches the request's contract before calling.
Type expected = ServiceDiscoveryProtocol.GetResponseType(req.GetType());
if (!expected.IsAssignableFrom(typeof(T)))
{
    throw new InvalidOperationException($"Response type {typeof(T)} does not match request {req.GetType()}");
}

public static bool IsExpectedResponse<TRequest, TResponse>()
    where TResponse : class, IResponse
{
    return typeof(TResponse) == ServiceDiscoveryProtocol.GetResponseType(typeof(TRequest));
}

catch (Exception e) when (e.Message.Contains("response type mismatch"))
{
    Log.Error($"discovery response contract mismatch - redeploy matching versions: {e.Message}");
    // trigger coordinated redeploy
}

When it happens

Trigger: ForwardToDiscoveryByFailover<T> is called with a T that does not match the response type the master produces for that request; an error/exception response object was returned instead of the success response; partial deployment where master and agent run different code versions with changed message definitions.

Common situations: Version skew between client and server message assemblies; a request routed to the wrong handler returning a different response type; proto/regeneration out of sync so the response class identity differs across processes.

Related errors

• service discovery incremental register response mismatch sce
• ERR_ServiceDiscoveryMasterUnavailable
• service discovery endpoint unavailable after resolve, reques
• service discovery response error, request: {requestName}, er
• service discovery request retry exhausted, request: {request

AI-assisted analysis of egametang/ET@5cab01f7a8 (2026-08-13). Data as JSON: /api/errors/6ec23c8d6780689f. Report an issue: GitHub.