[MM-62107] Remove the need to have the currently selected thread in the Unreads pane (#29876)

* [MM-62107] Remove the need to have the currently selected thread in the Unreads pane

* Remove selected thread from Followed Threads as well if it's not followed

---------

Co-authored-by: Caleb Roseland <caleb@calebroseland.com>

webapp/channels/src/components/threading/global_threads/global_threads.tsx

@@ -57,8 +57,8 @@ const GlobalThreads = () => {
     const selectedThread = useSelector((state: GlobalState) => getThread(state, threadIdentifier));
     const selectedThreadId = useSelector(getSelectedThreadIdInCurrentTeam);
     const selectedPost = useSelector((state: GlobalState) => getPost(state, threadIdentifier!));
-    const threadIds = useSelector((state: GlobalState) => getThreadOrderInCurrentTeam(state, selectedThread?.id), shallowEqual);
-    const unreadThreadIds = useSelector((state: GlobalState) => getUnreadThreadOrderInCurrentTeam(state, selectedThread?.id), shallowEqual);
+    const threadIds = useSelector((state: GlobalState) => getThreadOrderInCurrentTeam(state), shallowEqual);
+    const unreadThreadIds = useSelector((state: GlobalState) => getUnreadThreadOrderInCurrentTeam(state), shallowEqual);
     const numUnread = counts?.total_unread_threads || 0;
 
     useEffect(() => {
@@ -94,12 +94,8 @@ const GlobalThreads = () => {
 
     const [isLoading, setLoading] = useState(isEmptyList);
 
-    const isOnlySelectedThreadInList = (list: string[]) => {
-        return selectedThreadId && list.length === 1 && list[0] === selectedThreadId;
-    };
-
-    const shouldLoadThreads = isEmpty(threadIds) || isOnlySelectedThreadInList(threadIds);
-    const shouldLoadUnreadThreads = isEmpty(unreadThreadIds) || isOnlySelectedThreadInList(unreadThreadIds);
+    const shouldLoadThreads = isEmpty(threadIds);
+    const shouldLoadUnreadThreads = isEmpty(unreadThreadIds);
 
     useEffect(() => {
         const promises = [];

webapp/channels/src/packages/mattermost-redux/src/selectors/entities/threads.ts

@@ -104,22 +104,15 @@ export function makeGetThreadOrSynthetic(): (state: GlobalState, rootPost: Post)
     );
 }
 
-export const getThreadOrderInCurrentTeam: (state: GlobalState, selectedThreadIdInTeam?: UserThread['id']) => Array<UserThread['id']> = createSelector(
+export const getThreadOrderInCurrentTeam: (state: GlobalState) => Array<UserThread['id']> = createSelector(
     'getThreadOrderInCurrentTeam',
     getThreadsInCurrentTeam,
     getThreads,
-    (state: GlobalState, selectedThreadIdInTeam?: UserThread['id']) => selectedThreadIdInTeam,
     (
         threadsInTeam,
         threads,
-        selectedThreadIdInTeam,
     ) => {
         const ids = [...threadsInTeam.filter((id) => threads[id].is_following)];
-
-        if (selectedThreadIdInTeam && !ids.includes(selectedThreadIdInTeam)) {
-            ids.push(selectedThreadIdInTeam);
-        }
-
         return sortByLastReply(ids, threads);
     },
 );
@@ -145,26 +138,19 @@ export const getNewestThreadInTeam: (state: GlobalState, teamID: string,) => (Us
 
 export const getUnreadThreadOrderInCurrentTeam: (
     state: GlobalState,
-    selectedThreadIdInTeam?: UserThread['id'],
 ) => Array<UserThread['id']> = createSelector(
     'getUnreadThreadOrderInCurrentTeam',
     getUnreadThreadsInCurrentTeam,
     getThreads,
-    (state: GlobalState, selectedThreadIdInTeam?: UserThread['id']) => selectedThreadIdInTeam,
     (
         threadsInTeam,
         threads,
-        selectedThreadIdInTeam,
     ) => {
         const ids = threadsInTeam.filter((id) => {
             const thread = threads[id];
             return thread.is_following && (thread.unread_replies || thread.unread_mentions);
         });
 
-        if (selectedThreadIdInTeam && !ids.includes(selectedThreadIdInTeam)) {
-            ids.push(selectedThreadIdInTeam);
-        }
-
         return sortByLastReply(ids, threads);
     },
 );