[MM-43850] Separate leave_team events for associated user and team (#21231)

* Separate leave_team events for associated user and team

* Remove unnecessary change of sending mode

* Remove redundant get, set of message.broadcast

Co-authored-by: Mattermod <mattermod@users.noreply.github.com>

api4/team_test.go

@@ -2632,6 +2632,51 @@ func TestRemoveTeamMember(t *testing.T) {
 	require.NoError(t, err)
 }
 
+func TestRemoveTeamMemberEvents(t *testing.T) {
+	th := Setup(t).InitBasic()
+	defer th.TearDown()
+
+	client1 := th.CreateClient()
+	th.LoginBasicWithClient(client1)
+	WebSocketClient, err := th.CreateWebSocketClientWithClient(client1)
+	require.NoError(t, err)
+	defer WebSocketClient.Close()
+	WebSocketClient.Listen()
+	resp := <-WebSocketClient.ResponseChannel
+	require.Equal(t, resp.Status, model.StatusOk)
+
+	client2 := th.CreateClient()
+	th.LoginBasic2WithClient(client2)
+	WebSocketClient2, err := th.CreateWebSocketClientWithClient(client2)
+	require.NoError(t, err)
+	defer WebSocketClient2.Close()
+	WebSocketClient2.Listen()
+	resp = <-WebSocketClient2.ResponseChannel
+	require.Equal(t, resp.Status, model.StatusOk)
+
+	th.TestForSystemAdminAndLocal(t, func(t *testing.T, client *model.Client4) {
+		// remove second user from basic team
+		_, err := client.RemoveTeamMember(th.BasicTeam.Id, th.BasicUser2.Id)
+		require.NoError(t, err)
+
+		assertExpectedWebsocketEvent(t, WebSocketClient, model.WebsocketEventLeaveTeam, func(event *model.WebSocketEvent) {
+			eventUserId, ok := event.GetData()["user_id"].(string)
+			require.True(t, ok, "expected user")
+			// assert eventUser.Id is same as th.BasicUser.Id
+			assert.Equal(t, eventUserId, th.BasicUser2.Id)
+			// assert this event doesn't go to event creator
+			assert.Equal(t, event.GetBroadcast().OmitUsers[eventUserId], true)
+		})
+		assertExpectedWebsocketEvent(t, WebSocketClient2, model.WebsocketEventLeaveTeam, func(event *model.WebSocketEvent) {
+			eventUserId, ok := event.GetData()["user_id"].(string)
+			require.True(t, ok, "expected user")
+			// assert eventUser.Id is same as th.BasicUser.Id
+			assert.Equal(t, eventUserId, th.BasicUser2.Id)
+		})
+	})
+
+}
+
 func TestGetTeamStats(t *testing.T) {
 	th := Setup(t).InitBasic()
 	defer th.TearDown()

app/teams/teams.go

@@ -191,11 +191,25 @@ func (ts *TeamService) JoinUserToTeam(team *model.Team, user *model.User) (*mode
 // RemoveTeamMember removes the team member from the team. This method sends
 // the websocket message before actually removing so the user being removed gets it.
 func (ts *TeamService) RemoveTeamMember(teamMember *model.TeamMember) error {
-	message := model.NewWebSocketEvent(model.WebsocketEventLeaveTeam, teamMember.TeamId, "", "", nil, "")
-	message.Add("user_id", teamMember.UserId)
-	message.Add("team_id", teamMember.TeamId)
-	ts.wh.Publish(message)
+	/*
+		MM-43850: send leave_team event to user using `ReliableClusterSend` to improve safety
+	*/
+	// message for other team members
+	omitUsers := make(map[string]bool, 1)
+	omitUsers[teamMember.UserId] = true
+	messageTeam := model.NewWebSocketEvent(model.WebsocketEventLeaveTeam, teamMember.TeamId, "", "", omitUsers, "")
+	messageTeam.Add("user_id", teamMember.UserId)
+	messageTeam.Add("team_id", teamMember.TeamId)
+	ts.wh.Publish(messageTeam)
 
+	// message for teamMember.UserId
+	messageUser := model.NewWebSocketEvent(model.WebsocketEventLeaveTeam, "", "", teamMember.UserId, nil, "")
+	messageUser.Add("user_id", teamMember.UserId)
+	messageUser.Add("team_id", teamMember.TeamId)
+
+	ts.wh.Publish(messageUser)
+
+	// delete team member
 	teamMember.Roles = ""
 	teamMember.DeleteAt = model.GetMillis()