fix(llc): keep a channel usable after the user hides it or is removed from it

e2e_app/integration_test/channel_actions_test.dart

@@ -125,7 +125,6 @@ void main() {
   streamTestWithEnv(
     allureId: '12684',
     description: 'app does not crash when the user goes back after being removed from the open channel',
-    skip: 'https://linear.app/stream/issue/FLU-1085',
     body: (env) async {
       step('GIVEN the user opens a channel');
       await env.userRobot.login().openChannel();

e2e_app/integration_test/moderation_test.dart

@@ -170,7 +170,6 @@ void main() {
   streamTestWithEnv(
     allureId: '12791',
     description: 'user blocks the participant in a direct message channel',
-    skip: 'https://linear.app/stream/issue/FLU-1085',
     body: (env) async {
       step('GIVEN a direct message channel with the participant exists');
       await env.backendRobot.generateChannels(channelsCount: 1, messagesCount: 2, withDirectMessageChannel: true);
@@ -189,7 +188,6 @@ void main() {
   streamTestWithEnv(
     allureId: '12792',
     description: 'direct message channel disappears when the user blocks the participant',
-    skip: 'https://linear.app/stream/issue/FLU-1085',
     body: (env) async {
       step('GIVEN a direct message channel with the participant exists');
       await env.backendRobot.generateChannels(channelsCount: 1, messagesCount: 2, withDirectMessageChannel: true);

packages/stream_chat/CHANGELOG.md

@@ -7,6 +7,13 @@
 
 🔄 Changed
 
+- `ChannelState.copyWith(membership: null)` now clears the membership instead of keeping it, as it already did for `draft`.
+
+🐞 Fixed
+
+- Fixed a `Channel` becoming unusable after the current user hides it or is removed from it, for example by blocking the other member of a direct message.
+- Fixed `Channel.hidden` not following the `channel.hidden` and `channel.visible` events.
+- Fixed the current user's membership staying on a channel after they are removed from it.
 - `Attachment.type` is now `url_preview` for every attachment scraped from a link in the message text, including a link to an image or file. Use `Attachment.rawType` to read the type it was created or received with.
 - `Attachment.toJson` keeps the original `type` of an attachment scraped from a link, such as `video` or `image`, instead of writing `url_preview`.
 

packages/stream_chat/lib/src/client/channel/channel.dart

@@ -2268,6 +2268,13 @@ class Channel {
 
         if (isQueryingAround) this.state?.truncate();
         this.state?.updateChannelStateFromServer(channelState);
+
+        // Watching a channel the user hid or was removed from makes it one of
+        // the client's channels again.
+        if (cid case final cid? when watch) {
+          final isListed = _client.state.channels.containsKey(cid);
+          if (!isListed) _client.state.addChannels({cid: this});
+        }
       }
 
       // Submit for delivery reporting only when fetching the latest messages.

packages/stream_chat/lib/src/client/channel/channel_client_state.dart

@@ -42,6 +42,7 @@ class ChannelClientState {
       removeTypingEvent: _removeTypingEvent,
       removeWatcher: _removeWatcher,
       removeMember: _removeMember,
+      clearMembership: _clearMembership,
       updateMember: _updateMember,
       deleteMessagesFromUser: _deleteMessagesFromUser,
     );
@@ -92,6 +93,13 @@ class ChannelClientState {
     );
   }
 
+  // Clears the current user's membership after they leave or are removed from
+  // the channel.
+  void _clearMembership() {
+    if (channelState.membership == null) return;
+    _channelState = channelState.copyWith(membership: null);
+  }
+
   // Replaces the member matching the given member's user id in the channel
   // state. Does nothing if no member with the same user id exists.
   void _updateMember(Member member) {
@@ -581,7 +589,7 @@ class ChannelClientState {
       watchers: newWatchers.toList(),
       watcherCount: updatedState.watcherCount,
       members: updatedState.members,
-      membership: updatedState.membership,
+      membership: updatedState.membership ?? _channelState.membership,
       read: newReads.toList(),
       draft: updatedState.draft,
       pinnedMessages: newPinnedMessages,

packages/stream_chat/lib/src/client/channel/channel_event_handler.dart

@@ -110,6 +110,10 @@ class ChannelEventHandler {
         _onChannelTruncated(event);
       case EventType.channelUpdated:
         _onChannelUpdated(event);
+      case EventType.channelHidden:
+        _mutations.onChannelHiddenChanged(hidden: true);
+      case EventType.channelVisible:
+        _mutations.onChannelHiddenChanged(hidden: false);
     }
   }
 
@@ -121,6 +125,8 @@ class ChannelEventHandler {
         _onMemberAdded(event);
       case EventType.memberRemoved:
         _onMemberRemoved(event);
+      case EventType.notificationRemovedFromChannel:
+        _mutations.onCurrentUserRemoved(event.user!);
     }
   }
 
@@ -397,6 +403,9 @@ class ChannelEventHandler {
 
   void _onMemberRemoved(Event event) {
     final user = event.user!;
+    if (user.id == _client.state.currentUser?.id) {
+      return _mutations.onCurrentUserRemoved(user);
+    }
 
     return _mutations.onMemberRemoved(user);
   }

packages/stream_chat/lib/src/client/channel/channel_state_mutations.dart

@@ -15,6 +15,7 @@ class ChannelStateMutations {
     required this._removeTypingEvent,
     required this._removeWatcher,
     required this._removeMember,
+    required this._clearMembership,
     required this._updateMember,
     required this._deleteMessagesFromUser,
   });
@@ -26,6 +27,7 @@ class ChannelStateMutations {
   final void Function(User user) _removeTypingEvent;
   final void Function(User watcher, {int? watcherCount}) _removeWatcher;
   final void Function(User user) _removeMember;
+  final void Function() _clearMembership;
   final void Function(Member member) _updateMember;
   final Future<void> Function({
     required String userId,
@@ -430,6 +432,16 @@ class ChannelStateMutations {
     );
   }
 
+  /// Records whether the current user has [hidden] the channel.
+  void onChannelHiddenChanged({required bool hidden}) {
+    final channel = _state.channelState.channel;
+    if (channel == null) return;
+
+    _state.updateChannelState(
+      _state.channelState.copyWith(channel: channel.copyWith(hidden: hidden)),
+    );
+  }
+
   /// Updates the channel [memberCount] and [messageCount].
   ///
   /// A null count leaves the currently stored value unchanged.
@@ -458,6 +470,13 @@ class ChannelStateMutations {
   /// Removes the [user]'s membership and read state.
   void onMemberRemoved(User user) => _removeMember(user);
 
+  /// Removes the current user from the channel's members, read state and
+  /// membership after they leave or are removed from it.
+  void onCurrentUserRemoved(User user) {
+    _removeMember(user);
+    _clearMembership();
+  }
+
   /// Merges the updated [user] into the matching member and membership.
   ///
   /// Does nothing if the user is not an existing member of the channel.

packages/stream_chat/lib/src/client/client.dart

@@ -999,12 +999,14 @@ class StreamChatClient {
   MapEntry<Map<String, Channel>, List<Channel>> _mapChannelStateToChannel(
     List<ChannelState> channelStates,
   ) {
-    final channels = {...state.channels};
+    final channels = <String, Channel>{};
     final newChannels = <Channel>[];
     for (final channelState in channelStates) {
-      final channel = channels[channelState.channel!.cid];
+      final cid = channelState.channel!.cid;
+      final channel = state._channelFor(cid);
       if (channel != null) {
         channel.state?.updateChannelStateFromServer(channelState);
+        channels[cid] = channel;
         newChannels.add(channel);
       } else {
         final newChannel = Channel.fromState(this, channelState);
@@ -1318,8 +1320,8 @@ class StreamChatClient {
     String? id,
     Map<String, Object?>? extraData,
   }) {
-    if (id != null && state.channels.containsKey('$type:$id')) {
-      return state.channels['$type:$id']!;
+    if (id != null) {
+      if (state._channelFor('$type:$id') case final channel?) return channel;
     }
     return Channel(this, type, id, extraData: extraData);
   }
@@ -2596,6 +2598,7 @@ class ClientState {
     _listenChannelLeft();
     _listenChannelDeleted();
     _listenChannelHidden();
+    _listenChannelVisible();
     // endregion
 
     // region USER EVENTS
@@ -2636,8 +2639,16 @@ class ClientState {
     _eventsSubscription?.add(
       _client.on(EventType.channelHidden).listen((event) async {
         final eventChannel = event.channel!;
+        _unlistChannel(eventChannel.cid);
         await _client.chatPersistenceClient?.deleteChannels([eventChannel.cid]);
-        channels[eventChannel.cid]?.dispose();
+      }),
+    );
+  }
+
+  void _listenChannelVisible() {
+    _eventsSubscription?.add(
+      _client.on(EventType.channelVisible).listen((event) {
+        if (event.channel?.cid case final cid?) _relistChannel(cid);
       }),
     );
   }
@@ -2674,7 +2685,7 @@ class ClientState {
         if (event.cid != null) return;
 
         // Update all channels' unread count to 0.
-        for (final channel in channels.values) {
+        for (final channel in _channelsController.value.values) {
           channel.state?.unreadCount = 0;
         }
       }),
@@ -2692,8 +2703,8 @@ class ClientState {
             final isCurrentUser = event.user!.id == currentUser!.id;
             if (isCurrentUser && event.channel != null) {
               final eventChannel = event.channel!;
+              _unlistChannel(eventChannel.cid);
               await _client.chatPersistenceClient?.deleteChannels([eventChannel.cid]);
-              channels[eventChannel.cid]?.dispose();
             }
           }),
     );
@@ -2709,7 +2720,7 @@ class ClientState {
           .listen((Event event) async {
             final eventChannel = event.channel!;
             await _client.chatPersistenceClient?.deleteChannels([eventChannel.cid]);
-            channels[eventChannel.cid]?.dispose();
+            _channelFor(eventChannel.cid)?.dispose();
           }),
     );
   }
@@ -2724,7 +2735,7 @@ class ClientState {
 
         // Iterate through all the available channels and send the event
         // to be handled by the respective channel instances.
-        for (final cid in [...channels.keys]) {
+        for (final cid in [..._channelsController.value.keys]) {
           final channelEvent = event.copyWith(cid: cid);
           _client.handleEvent(channelEvent);
         }
@@ -2895,29 +2906,65 @@ class ClientState {
   /// The current total unread messages count as a stream
   Stream<int> get totalUnreadCountStream => _totalUnreadCountController.stream.distinct();
 
-  /// The current list of channels in memory as a stream
-  Stream<Map<String, Channel>> get channelsStream => _channelsController.stream;
+  /// The channels in memory as a stream, leaving out the ones the current user
+  /// hid or was removed from.
+  Stream<Map<String, Channel>> get channelsStream {
+    return _channelsController.stream.map(_listedChannels);
+  }
 
-  /// The current list of channels in memory
-  Map<String, Channel> get channels => _channelsController.value;
+  /// The channels in memory, leaving out the ones the current user hid or was
+  /// removed from.
+  Map<String, Channel> get channels => _listedChannels(_channelsController.value);
 
   @internal
   set channels(Map<String, Channel> newChannels) {
+    _unlistedCids.clear();
     _channelsController.safeAdd(newChannels);
   }
 
   /// Adds a list of channels to the current list of cached channels
   @internal
   void addChannels(Map<String, Channel> channelMap) {
-    final newChannels = {...channels, ...channelMap};
-    channels = newChannels;
+    _unlistedCids.removeAll(channelMap.keys);
+    _channelsController.safeAdd({..._channelsController.value, ...channelMap});
   }
 
   /// Removes the channel from the cached list of [channels]
   @internal
   void removeChannel(String channelCid) {
-    if (!channels.containsKey(channelCid)) return;
-    channels = {...channels}..remove(channelCid);
+    _unlistedCids.remove(channelCid);
+    if (!_channelsController.value.containsKey(channelCid)) return;
+    _channelsController.safeAdd({..._channelsController.value}..remove(channelCid));
+  }
+
+  // The live channel for [cid], including one the current user hid or was
+  // removed from.
+  Channel? _channelFor(String cid) => _channelsController.value[cid];
+
+  // Leaves the channel out of [channels] without disposing it, so code still
+  // holding it keeps working. Watching it, a channels query returning it, or a
+  // channel.visible event lists it again.
+  void _unlistChannel(String cid) {
+    if (!_channelsController.value.containsKey(cid)) return;
+    if (!_unlistedCids.add(cid)) return;
+
+    _channelsController.safeAdd(_channelsController.value);
+  }
+
+  // Puts a channel left out by [_unlistChannel] back into [channels].
+  void _relistChannel(String cid) {
+    if (!_unlistedCids.remove(cid)) return;
+
+    _channelsController.safeAdd(_channelsController.value);
+  }
+
+  Map<String, Channel> _listedChannels(Map<String, Channel> channels) {
+    if (_unlistedCids.isEmpty) return channels;
+
+    return Map.unmodifiable({
+      for (final MapEntry(:key, :value) in channels.entries)
+        if (!_unlistedCids.contains(key)) key: value,
+    });
   }
 
   @internal
@@ -2945,7 +2992,11 @@ class ClientState {
     }
   }
 
+  // Every live channel, including the ones left out of [channels].
   final _channelsController = ImmutableMapBehaviorSubject<String, Channel>.seeded(const {});
+  // The channels the current user hid or was removed from, left out of
+  // [channels] until they are listed again.
+  final _unlistedCids = <String>{};
   final _currentUserController = BehaviorSubject<OwnUser?>();
   final _usersController = ImmutableMapBehaviorSubject<String, User>.seeded(const {});
   final _unreadChannelsController = BehaviorSubject<int>.seeded(0);
@@ -2964,8 +3015,9 @@ class ClientState {
     _activeLiveLocationsController.close();
     _locationExpirationScheduler.cancel();
 
+    final remainingChannels = _channelsController.value.values;
     _channelsController.close();
-    for (final channel in channels.values) {
+    for (final channel in remainingChannels) {
       channel.dispose(); // Dispose any remaining channels in memory.
     }
   }

packages/stream_chat/lib/src/core/models/channel_state.dart

@@ -98,6 +98,9 @@ class ChannelState implements ComparableFieldProvider {
   Map<String, dynamic> toJson() => _$ChannelStateToJson(this);
 
   /// Creates a copy of [ChannelState] with specified attributes overridden.
+  ///
+  /// Passing null for [membership] or [draft] clears it, while leaving it out
+  /// keeps the current value.
   ChannelState copyWith({
     ChannelModel? channel,
     List<Message>? messages,
@@ -106,7 +109,7 @@ class ChannelState implements ComparableFieldProvider {
     int? watcherCount,
     List<User>? watchers,
     List<Read>? read,
-    Member? membership,
+    Object? membership = _nullConst,
     Object? draft = _nullConst,
     List<Message>? pendingMessages,
     ChannelPushPreference? pushPreferences,
@@ -119,7 +122,7 @@ class ChannelState implements ComparableFieldProvider {
     watcherCount: watcherCount ?? this.watcherCount,
     watchers: watchers ?? this.watchers,
     read: read ?? this.read,
-    membership: membership ?? this.membership,
+    membership: membership == _nullConst ? this.membership : membership as Member?,
     draft: draft == _nullConst ? this.draft : draft as Draft?,
     pendingMessages: pendingMessages ?? this.pendingMessages,
     pushPreferences: pushPreferences ?? this.pushPreferences,

packages/stream_chat/test/src/client/channel/channel_state_mutations_test.dart

@@ -59,6 +59,7 @@ void main() {
       removeTypingEvent: removeTypingEventCalls.add,
       removeWatcher: (watcher, {watcherCount}) => removeWatcherCalls.add((watcher, watcherCount)),
       removeMember: removeMemberCalls.add,
+      clearMembership: () {},
       updateMember: updateMemberCalls.add,
       deleteMessagesFromUser: ({required userId, hardDelete = false, deletedAt}) async {
         deleteMessagesFromUserCalls.add((userId, hardDelete, deletedAt));