Handle network errors better when returning remote HTTP errors

federationsender/internal/perform.go

@@ -90,7 +90,6 @@ func (r *FederationSenderInternalAPI) PerformJoin(
 	// If we reach here then we didn't complete a join for some reason.
 	var httpErr gomatrix.HTTPError
 	if ok := errors.As(lastErr, &httpErr); ok {
-		logrus.Infof("TYPE CAST LASTERR OK!")
 		httpErr.Message = string(httpErr.Contents)
 		response.LastError = &httpErr
 	} else {

federationsender/inthttp/client.go

@@ -87,7 +87,7 @@ func (h *httpFederationSenderInternalAPI) PerformJoin(
 	if err != nil {
 		response.LastError = &gomatrix.HTTPError{
 			Message:      err.Error(),
-			Code:         599, // to distinguish from genuine 500
+			Code:         0,
 			WrappedError: err,
 		}
 	}

roomserver/api/perform.go

@@ -46,12 +46,13 @@ func (p *PerformError) JSONResponse() util.JSONResponse {
 			JSON: jsonerror.Forbidden(p.Msg),
 		}
 	case PerformErrRemote:
-		code := p.RemoteCode
-		if code == 0 {
-			code = 500
+		// if the code is 0 then something bad happened and it isn't
+		// a remote HTTP error being encapsulated, e.g network error to remote.
+		if p.RemoteCode == 0 {
+			return util.ErrorResponse(fmt.Errorf("%s", p.Msg))
 		}
 		return util.JSONResponse{
-			Code: code,
+			Code: p.RemoteCode,
 			// TODO: Should we assert this is in fact JSON? E.g gjson parse?
 			JSON: json.RawMessage(p.Msg),
 		}