From b9024f51839bba52598709a7ad91021ef34322f5 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Daniel=20Espino=20Garc=C3=ADa?= <larkox@gmail.com>
Date: Tue, 31 Oct 2023 15:59:54 +0100
Subject: [PATCH] Fix error around combined user activity (#7637)

---
 .../combined_user_activity.tsx                | 38 +++++++++++--------
 .../post_list/combined_user_activity/index.ts | 27 +++++++------
 2 files changed, 39 insertions(+), 26 deletions(-)

diff --git a/app/components/post_list/combined_user_activity/combined_user_activity.tsx b/app/components/post_list/combined_user_activity/combined_user_activity.tsx
index f29225ba0..845688c04 100644
--- a/app/components/post_list/combined_user_activity/combined_user_activity.tsx
+++ b/app/components/post_list/combined_user_activity/combined_user_activity.tsx
@@ -25,7 +25,7 @@ type Props = {
     currentUserId?: string;
     currentUsername?: string;
     location: string;
-    post: Post;
+    post: Post | null;
     showJoinLeave: boolean;
     testID?: string;
     theme: Theme;
@@ -65,23 +65,11 @@ const CombinedUserActivity = ({
     const intl = useIntl();
     const isTablet = useIsTablet();
     const serverUrl = useServerUrl();
-    const itemTestID = `${testID}.${post.id}`;
     const textStyles = getMarkdownTextStyles(theme);
-    const {allUserIds, allUsernames, messageData} = post.props.user_activity;
     const styles = getStyleSheet(theme);
     const content = [];
     const removedUserIds: string[] = [];
 
-    const loadUserProfiles = () => {
-        if (allUserIds.length) {
-            fetchMissingProfilesByIds(serverUrl, allUserIds);
-        }
-
-        if (allUsernames.length) {
-            fetchMissingProfilesByUsernames(serverUrl, allUsernames);
-        }
-    };
-
     const getUsernames = (userIds: string[]) => {
         const someone = intl.formatMessage({id: 'channel_loader.someone', defaultMessage: 'Someone'});
         const you = intl.formatMessage({id: 'combined_system_message.you', defaultMessage: 'You'});
@@ -120,6 +108,9 @@ const CombinedUserActivity = ({
     }, [post, canDelete, isTablet, intl, location]);
 
     const renderMessage = (postType: string, userIds: string[], actorId: string) => {
+        if (!post) {
+            return null;
+        }
         let actor = '';
         if (usernamesById[actorId]) {
             actor = `@${usernamesById[actorId]}`;
@@ -177,9 +168,26 @@ const CombinedUserActivity = ({
     };
 
     useEffect(() => {
-        loadUserProfiles();
-    }, [allUserIds, allUsernames]);
+        if (!post) {
+            return;
+        }
 
+        const {allUserIds, allUsernames} = post.props.user_activity;
+        if (allUserIds.length) {
+            fetchMissingProfilesByIds(serverUrl, allUserIds);
+        }
+
+        if (allUsernames.length) {
+            fetchMissingProfilesByUsernames(serverUrl, allUsernames);
+        }
+    }, [post?.props.user_activity.allUserIds, post?.props.user_activity.allUsernames]);
+
+    if (!post) {
+        return null;
+    }
+
+    const itemTestID = `${testID}.${post.id}`;
+    const {messageData} = post.props.user_activity;
     for (const message of messageData) {
         const {postType, actorId} = message;
         const userIds = new Set<string>(message.userIds);
diff --git a/app/components/post_list/combined_user_activity/index.ts b/app/components/post_list/combined_user_activity/index.ts
index 72bcfa6cb..32842e06e 100644
--- a/app/components/post_list/combined_user_activity/index.ts
+++ b/app/components/post_list/combined_user_activity/index.ts
@@ -28,24 +28,29 @@ const withCombinedPosts = withObservables(['postId'], ({database, postId}: WithD
 
     // Columns observed: `props` is used by `usernamesById`. `message` is used by generateCombinedPost.
     const posts = queryPostsById(database, postIds).observeWithColumns(['props', 'message']);
-    const post = posts.pipe(map((ps) => generateCombinedPost(postId, ps)));
+    const post = posts.pipe(map((ps) => (ps.length ? generateCombinedPost(postId, ps) : null)));
     const canDelete = combineLatest([posts, currentUser]).pipe(
         switchMap(([ps, u]) => (ps.length ? observePermissionForPost(database, ps[0], u, Permissions.DELETE_OTHERS_POSTS, false) : of$(false))),
     );
 
     const usernamesById = post.pipe(
         switchMap(
-            (p) => queryUsersByIdsOrUsernames(database, p.props.user_activity.allUserIds, p.props.user_activity.allUsernames).observeWithColumns(['username']).
-                pipe(
-                    // eslint-disable-next-line max-nested-callbacks
-                    switchMap((users) => {
+            (p) => {
+                if (!p) {
+                    return of$<Record<string, string>>({});
+                }
+                return queryUsersByIdsOrUsernames(database, p.props.user_activity.allUserIds, p.props.user_activity.allUsernames).observeWithColumns(['username']).
+                    pipe(
                         // eslint-disable-next-line max-nested-callbacks
-                        return of$(users.reduce((acc: Record<string, string>, user) => {
-                            acc[user.id] = user.username;
-                            return acc;
-                        }, {}));
-                    }),
-                ),
+                        switchMap((users) => {
+                            // eslint-disable-next-line max-nested-callbacks
+                            return of$(users.reduce((acc: Record<string, string>, user) => {
+                                acc[user.id] = user.username;
+                                return acc;
+                            }, {}));
+                        }),
+                    );
+            },
         ),
     );