checkAndProcessThreepid function added in membership.go to reduce reduce the complexity of SendMembership in order to Fix response to /rooms/{roomId}/join

src/github.com/matrix-org/dendrite/clientapi/routing/membership.go

@@ -58,27 +58,12 @@ func SendMembership(
 		}
 	}
 
-	inviteStored, err := threepid.CheckAndProcessInvite(
+	inviteStored, errRes := checkAndProcessThreepid(
-		req.Context(), device, &body, cfg, queryAPI, accountDB, producer,
+		req, device, &body, cfg, queryAPI, accountDB, producer,
 		membership, roomID, evTime,
 	)
-	if err == threepid.ErrMissingParameter {
+	if errRes != nil {
-		return util.JSONResponse{
+		return *errRes
-			Code: http.StatusBadRequest,
-			JSON: jsonerror.BadJSON(err.Error()),
-		}
-	} else if err == threepid.ErrNotTrusted {
-		return util.JSONResponse{
-			Code: http.StatusBadRequest,
-			JSON: jsonerror.NotTrusted(body.IDServer),
-		}
-	} else if err == common.ErrRoomNoExists {
-		return util.JSONResponse{
-			Code: http.StatusNotFound,
-			JSON: jsonerror.NotFound(err.Error()),
-		}
-	} else if err != nil {
-		return httputil.LogThenError(req, err)
 	}
 
 	// If an invite has been stored on an identity server, it means that a
@@ -114,6 +99,15 @@ func SendMembership(
 		return httputil.LogThenError(req, err)
 	}
 
+	if membership == "join" {
+		return util.JSONResponse{
+			Code: http.StatusOK,
+			JSON: struct {
+				RoomID string `json:"room_id"`
+			}{roomID},
+		}
+	}
+
 	return util.JSONResponse{
 		Code: http.StatusOK,
 		JSON: struct{}{},
@@ -215,3 +209,35 @@ func getMembershipStateKey(
 
 	return
 }
+
+func checkAndProcessThreepid(
+	req *http.Request, device *authtypes.Device, body *threepid.MembershipRequest,
+	cfg config.Dendrite, queryAPI roomserverAPI.RoomserverQueryAPI, accountDB *accounts.Database,
+	producer *producers.RoomserverProducer, membership string, roomID string, evTime time.Time,
+) (inviteStored bool, errRes *util.JSONResponse) {
+
+	inviteStored, err := threepid.CheckAndProcessInvite(
+		req.Context(), device, body, cfg, queryAPI, accountDB, producer,
+		membership, roomID, evTime,
+	)
+	if err == threepid.ErrMissingParameter {
+		return inviteStored, &util.JSONResponse{
+			Code: http.StatusBadRequest,
+			JSON: jsonerror.BadJSON(err.Error()),
+		}
+	} else if err == threepid.ErrNotTrusted {
+		return inviteStored, &util.JSONResponse{
+			Code: http.StatusBadRequest,
+			JSON: jsonerror.NotTrusted(body.IDServer),
+		}
+	} else if err == common.ErrRoomNoExists {
+		return inviteStored, &util.JSONResponse{
+			Code: http.StatusNotFound,
+			JSON: jsonerror.NotFound(err.Error()),
+		}
+	} else if err != nil {
+		er := httputil.LogThenError(req, err)
+		return inviteStored, &er
+	}
+	return
+}

src/github.com/matrix-org/dendrite/clientapi/routing/routing.go

@@ -95,14 +95,7 @@ func Setup(
 	r0mux.Handle("/rooms/{roomID}/{membership:(?:join|kick|ban|unban|leave|invite)}",
 		common.MakeAuthAPI("membership", authData, func(req *http.Request, device *authtypes.Device) util.JSONResponse {
 			vars := mux.Vars(req)
-			r := SendMembership(req, accountDB, device, vars["roomID"], vars["membership"], cfg, queryAPI, asAPI, producer)
+			return SendMembership(req, accountDB, device, vars["roomID"], vars["membership"], cfg, queryAPI, asAPI, producer)
-			if r.Code == http.StatusOK && vars["membership"] == "join" {
-				r.JSON = struct {
-					RoomID string `json:"room_id"`
-				}{vars["roomID"]}
-				return r
-			}
-			return r
 		}),
 	).Methods(http.MethodPost, http.MethodOptions)
 	r0mux.Handle("/rooms/{roomID}/send/{eventType}",