fix(llc): keep Channel.memberCount fresh from channel events, make primitive value streams distinct

packages/stream_chat/CHANGELOG.md

@@ -1,9 +1,21 @@
 ## Upcoming
 
+✅ Added
+
+- Added `Event.channelMemberCount`, exposing the server-provided `channel_member_count` field on channel events (e.g. `member.added`, `member.removed`, `member.updated`).
+
+🔄 Changed
+
+- `Channel` and `ClientState` streams that expose a single primitive value are now distinct, so they only emit when the value actually changes. Affects `Channel.memberCountStream`, `messageCountStream`, `watcherCountStream`, `cooldownStream`, `nameStream`, `imageStream`, `frozenStream`, `disabledStream`, `hiddenStream`, `isPinnedStream`, `isArchivedStream`, `createdAtStream`, `updatedAtStream`, `deletedAtStream`, `truncatedAtStream`, `lastMessageAtStream`, and `ClientState.totalUnreadCountStream`, `unreadChannelsStream`, `unreadThreadsStream`.
+
 ⚠️ Deprecated
 
 - Deprecated `StreamChatClient.unflagMessage` and `StreamChatClient.unflagUser`. The `/moderation/unflag` endpoint is no longer supported by the server and the calls have no effect; both methods will be removed in a future major release.
 
+🐞 Fixed
+
+- Fixed `Channel.memberCount` / `memberCountStream` staying stale for the rest of the session after members joined or left; channel events now apply the server-provided member count, the same way `messageCount` already did.
+
 ## 9.28.0
 
 ✅ Added

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

@@ -207,7 +207,9 @@ class Channel {
   /// Channel frozen status as a stream.
   Stream<bool> get frozenStream {
     _checkInitialized();
-    return state!.channelStateStream.map((cs) => cs.channel?.frozen == true);
+    return state!.channelStateStream
+        .map((cs) => cs.channel?.frozen == true)
+        .distinct();
   }
 
   /// Channel disabled status.
@@ -219,7 +221,9 @@ class Channel {
   /// Channel disabled status as a stream.
   Stream<bool> get disabledStream {
     _checkInitialized();
-    return state!.channelStateStream.map((cs) => cs.channel?.disabled == true);
+    return state!.channelStateStream
+        .map((cs) => cs.channel?.disabled == true)
+        .distinct();
   }
 
   /// Channel hidden status.
@@ -231,7 +235,9 @@ class Channel {
   /// Channel hidden status as a stream.
   Stream<bool> get hiddenStream {
     _checkInitialized();
-    return state!.channelStateStream.map((cs) => cs.channel?.hidden == true);
+    return state!.channelStateStream
+        .map((cs) => cs.channel?.hidden == true)
+        .distinct();
   }
 
   /// Channel pinned status.
@@ -244,7 +250,7 @@ class Channel {
   /// Channel pinned status as a stream.
   /// Status is specific to the current user.
   Stream<bool> get isPinnedStream {
-    return membershipStream.map((m) => m?.pinnedAt != null);
+    return membershipStream.map((m) => m?.pinnedAt != null).distinct();
   }
 
   /// Channel archived status.
@@ -257,7 +263,7 @@ class Channel {
   /// Channel archived status as a stream.
   /// Status is specific to the current user.
   Stream<bool> get isArchivedStream {
-    return membershipStream.map((m) => m?.archivedAt != null);
+    return membershipStream.map((m) => m?.archivedAt != null).distinct();
   }
 
   /// The last date at which the channel got truncated.
@@ -269,7 +275,9 @@ class Channel {
   /// The last date at which the channel got truncated as a stream.
   Stream<DateTime?> get truncatedAtStream {
     _checkInitialized();
-    return state!.channelStateStream.map((cs) => cs.channel?.truncatedAt);
+    return state!.channelStateStream
+        .map((cs) => cs.channel?.truncatedAt)
+        .distinct();
   }
 
   /// Cooldown count
@@ -281,7 +289,9 @@ class Channel {
   /// Cooldown count as a stream
   Stream<int> get cooldownStream {
     _checkInitialized();
-    return state!.channelStateStream.map((cs) => cs.channel?.cooldown ?? 0);
+    return state!.channelStateStream
+        .map((cs) => cs.channel?.cooldown ?? 0)
+        .distinct();
   }
 
   /// Remaining cooldown duration in seconds for the channel.
@@ -322,7 +332,9 @@ class Channel {
   /// Channel creation date as a stream.
   Stream<DateTime?> get createdAtStream {
     _checkInitialized();
-    return state!.channelStateStream.map((cs) => cs.channel?.createdAt);
+    return state!.channelStateStream
+        .map((cs) => cs.channel?.createdAt)
+        .distinct();
   }
 
   /// Channel last message date.
@@ -334,7 +346,9 @@ class Channel {
   /// Channel last message date as a stream.
   Stream<DateTime?> get lastMessageAtStream {
     _checkInitialized();
-    return state!.channelStateStream.map((cs) => cs.channel?.lastMessageAt);
+    return state!.channelStateStream
+        .map((cs) => cs.channel?.lastMessageAt)
+        .distinct();
   }
 
   DateTime? _currentUserLastMessageAt(List<Message>? messages) {
@@ -387,7 +401,9 @@ class Channel {
   /// Channel updated date as a stream.
   Stream<DateTime?> get updatedAtStream {
     _checkInitialized();
-    return state!.channelStateStream.map((cs) => cs.channel?.updatedAt);
+    return state!.channelStateStream
+        .map((cs) => cs.channel?.updatedAt)
+        .distinct();
   }
 
   /// Channel deletion date.
@@ -399,7 +415,9 @@ class Channel {
   /// Channel deletion date as a stream.
   Stream<DateTime?> get deletedAtStream {
     _checkInitialized();
-    return state!.channelStateStream.map((cs) => cs.channel?.deletedAt);
+    return state!.channelStateStream
+        .map((cs) => cs.channel?.deletedAt)
+        .distinct();
   }
 
   /// Channel member count.
@@ -411,7 +429,9 @@ class Channel {
   /// Channel member count as a stream.
   Stream<int?> get memberCountStream {
     _checkInitialized();
-    return state!.channelStateStream.map((cs) => cs.channel?.memberCount);
+    return state!.channelStateStream
+        .map((cs) => cs.channel?.memberCount)
+        .distinct();
   }
 
   /// Channel message count.
@@ -429,7 +449,9 @@ class Channel {
   /// enabled for your app.
   Stream<int?> get messageCountStream {
     _checkInitialized();
-    return state!.channelStateStream.map((cs) => cs.channel?.messageCount);
+    return state!.channelStateStream
+        .map((cs) => cs.channel?.messageCount)
+        .distinct();
   }
 
   /// List of filter tags applied to this channel.
@@ -496,7 +518,7 @@ class Channel {
   /// {@macro name}
   Stream<String?> get nameStream {
     _checkInitialized();
-    return extraDataStream.map((it) => it['name'] as String?);
+    return extraDataStream.map((it) => it['name'] as String?).distinct();
   }
 
   /// Shortcut to get channel image.
@@ -511,7 +533,7 @@ class Channel {
   /// {@macro image}
   Stream<String?> get imageStream {
     _checkInitialized();
-    return extraDataStream.map((it) => it['image'] as String?);
+    return extraDataStream.map((it) => it['image'] as String?).distinct();
   }
 
   /// The main Stream chat client.
@@ -2246,7 +2268,7 @@ class ChannelClientState {
 
     _listenChannelUpdated();
 
-    _listenChannelMessageCount();
+    _listenChannelCounts();
 
     _listenMemberAdded();
 
@@ -2381,15 +2403,21 @@ class ChannelClientState {
     }));
   }
 
-  void _listenChannelMessageCount() {
+  // Most channel events carry the channel's member and message counts as
+  // event metadata, reflecting the authoritative values after the change.
+  // Applying them keeps the counts fresh for the whole session instead of
+  // only right after a `query` / `watch`.
+  void _listenChannelCounts() {
     _subscriptions.add(_channel.on().listen(
       (Event e) {
+        final memberCount = e.channelMemberCount;
         final messageCount = e.channelMessageCount;
-        if (messageCount == null) return;
+        if (memberCount == null && messageCount == null) return;
 
         updateChannelState(
           channelState.copyWith(
             channel: channelState.channel?.copyWith(
+              memberCount: memberCount,
               messageCount: messageCount,
             ),
           ),
@@ -3265,7 +3293,7 @@ class ChannelClientState {
 
   /// Channel watcher count as a stream.
   Stream<int?> get watcherCountStream =>
-      channelStateStream.map((cs) => cs.watcherCount);
+      channelStateStream.map((cs) => cs.watcherCount).distinct();
 
   /// Channel watchers list.
   List<User> get watchers => (_channelState.watchers ?? <User>[])

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

@@ -2588,19 +2588,22 @@ class ClientState {
   int get unreadChannels => _unreadChannelsController.value;
 
   /// The current unread channels count as a stream
-  Stream<int> get unreadChannelsStream => _unreadChannelsController.stream;
+  Stream<int> get unreadChannelsStream =>
+      _unreadChannelsController.stream.distinct();
 
   /// The current unread thread count.
   int get unreadThreads => _unreadThreadsController.value;
 
   /// The current unread threads count as a stream.
-  Stream<int> get unreadThreadsStream => _unreadThreadsController.stream;
+  Stream<int> get unreadThreadsStream =>
+      _unreadThreadsController.stream.distinct();
 
   /// The current total unread messages count
   int get totalUnreadCount => _totalUnreadCountController.value;
 
   /// The current total unread messages count as a stream
-  Stream<int> get totalUnreadCountStream => _totalUnreadCountController.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;

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

@@ -43,6 +43,7 @@ class Event {
     this.reminder,
     this.pushPreference,
     this.channelPushPreference,
+    this.channelMemberCount,
     this.channelMessageCount,
     this.watcherCount,
     this.lastDeliveredAt,
@@ -166,6 +167,13 @@ class Event {
   /// Push notification preferences for the current user for this channel.
   final ChannelPushPreference? channelPushPreference;
 
+  /// The total number of members in the channel.
+  ///
+  /// Sent with channel events such as `member.added`, `member.removed` and
+  /// `member.updated`, reflecting the authoritative member count after the
+  /// change.
+  final int? channelMemberCount;
+
   /// The total number of messages in the channel.
   final int? channelMessageCount;
 
@@ -222,6 +230,7 @@ class Event {
     'reminder',
     'push_preference',
     'channel_push_preference',
+    'channel_member_count',
     'channel_message_count',
     'watcher_count',
     'last_delivered_at',
@@ -269,6 +278,7 @@ class Event {
     MessageReminder? reminder,
     PushPreference? pushPreference,
     ChannelPushPreference? channelPushPreference,
+    int? channelMemberCount,
     int? channelMessageCount,
     int? watcherCount,
     DateTime? lastDeliveredAt,
@@ -311,6 +321,7 @@ class Event {
         pushPreference: pushPreference ?? this.pushPreference,
         channelPushPreference:
             channelPushPreference ?? this.channelPushPreference,
+        channelMemberCount: channelMemberCount ?? this.channelMemberCount,
         channelMessageCount: channelMessageCount ?? this.channelMessageCount,
         watcherCount: watcherCount ?? this.watcherCount,
         lastDeliveredAt: lastDeliveredAt ?? this.lastDeliveredAt,

packages/stream_chat/test/fixtures/event.json

@@ -31,5 +31,6 @@
   "unread_thread_messages": 2,
   "unread_threads": 3,
   "channel_last_message_at": "2019-03-27T17:40:17.155892Z",
-  "watcher_count": 12
+  "watcher_count": 12,
+  "channel_member_count": 4
 }