Improve accuracy of in-memory updates of LivestreamChannelController (#3787)

* Change livestream controller to handle membership updates in-memory

* Handle channel updated event manually

* Make sure deletedAt is always updated for soft deleted message

* Use channel updater sync

* Update channel.pinnedMessages when a message is pinned

* Make Channel.membership internal set

* Fix crash when removing a pinned message

* Add test coverage to membership updates

* Add test coverage to manual channel updates

* Add test coverage to pinned messages update

* Add test coverage to change of channel sync

* Fix channel mock not compiling

* Update CHANGELOG.md

* Fix tests

Author: nuno-vieira

CHANGELOG.md

@@ -5,9 +5,14 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/).
 
 ## StreamChat
 ### 🐞 Fixed
-- Fix LivestreamChannelController not reconnecting when connection is dropped [#3782](https://github.com/GetStream/stream-chat-swift/pull/3782)
+- Fix `LivestreamChannelController` not reconnecting when connection is dropped [#3782](https://github.com/GetStream/stream-chat-swift/pull/3782)
 - Fix `StreamAudioRecorder` not overridable because of init method [#3783](https://github.com/GetStream/stream-chat-swift/pull/3783)
 - Fix channel list query filtering by both blocked and non-blocked channels [#3785](https://github.com/GetStream/stream-chat-swift/pull/3785)
+- Fix `LivestreamChannelController.synchronize()` not working if client not connected [#3787](https://github.com/GetStream/stream-chat-swift/pull/3787)
+- Fix membership updates in `LivestreamChannelController` [#3787](https://github.com/GetStream/stream-chat-swift/pull/3787)
+- Fix deleted messages updates in `LivestreamChannelController` [#3787](https://github.com/GetStream/stream-chat-swift/pull/3787)
+- Fix `channel.pinnedMessages` not updated when pinning a message in `LivestreamChannelController` [#3787](https://github.com/GetStream/stream-chat-swift/pull/3787)
+- Fix `LivestreamChannelController` not watching the channel automatically when the current user joins the channel [#3787](https://github.com/GetStream/stream-chat-swift/pull/3787)
 
 # [4.85.0](https://github.com/GetStream/stream-chat-swift/releases/tag/4.85.0)
 _August 13, 2025_

Sources/StreamChat/Controllers/ChannelController/LivestreamChannelController.swift

@@ -832,13 +832,6 @@ public class LivestreamChannelController: DataStoreProvider, EventsControllerDel
 
                 switch result {
                 case .success(let payload):
-                    // If it is the first page, save channel to the DB to make sure manual event handling
-                    // can fetch the channel from the DB.
-                    if channelQuery.pagination == nil {
-                        client.databaseContainer.write { session in
-                            try session.saveChannel(payload: payload)
-                        }
-                    }
                     self.handleChannelPayload(payload, channelQuery: channelQuery)
                     completion?(nil)
 
@@ -851,7 +844,11 @@ public class LivestreamChannelController: DataStoreProvider, EventsControllerDel
             }
         }
 
-        apiClient.request(endpoint: endpoint, completion: requestCompletion)
+        updater.update(
+            channelQuery: channelQuery,
+            isInRecoveryMode: false,
+            completion: requestCompletion
+        )
     }
 
     private func handleChannelPayload(_ payload: ChannelPayload, channelQuery: ChannelQuery) {
@@ -936,7 +933,10 @@ public class LivestreamChannelController: DataStoreProvider, EventsControllerDel
                 handleDeletedMessage(messageDeletedEvent.message)
                 return
             }
-            handleUpdatedMessage(messageDeletedEvent.message)
+            let deletedMessage = messageDeletedEvent.message.changing(
+                deletedAt: messageDeletedEvent.createdAt
+            )
+            handleUpdatedMessage(deletedMessage)
 
         case let newMessageErrorEvent as NewMessageErrorEvent:
             guard let message = messages.first(where: { $0.id == newMessageErrorEvent.messageId }) else {
@@ -957,15 +957,73 @@ public class LivestreamChannelController: DataStoreProvider, EventsControllerDel
         case let channelUpdatedEvent as ChannelUpdatedEvent:
             handleChannelUpdated(channelUpdatedEvent)
 
-        case is MemberAddedEvent,
-             is MemberRemovedEvent,
-             is MemberUpdatedEvent,
-             is NotificationAddedToChannelEvent,
-             is NotificationRemovedFromChannelEvent,
-             is NotificationInvitedEvent,
-             is NotificationInviteAcceptedEvent,
-             is NotificationInviteRejectedEvent:
-            updateChannelFromDataStore()
+        case let notificationAddedToChannelEvent as NotificationAddedToChannelEvent:
+            var members = Set(channel?.lastActiveMembers ?? [])
+            members.insert(notificationAddedToChannelEvent.member)
+            let memberCount = channel?.memberCount ?? 0
+            channel = channel?.changing(
+                members: Array(members),
+                membership: notificationAddedToChannelEvent.member,
+                memberCount: memberCount + 1
+            )
+            startWatching(isInRecoveryMode: false)
+
+        case let notificationRemovedFromChannelEvent as NotificationRemovedFromChannelEvent:
+            var members = channel?.lastActiveMembers ?? []
+            members.removeAll(where: { $0.id == notificationRemovedFromChannelEvent.user.id })
+            let memberCount = channel?.memberCount ?? 0
+
+            channel = channel?.changing(members: members, memberCount: memberCount - 1)
+            channel?.membership = nil
+
+        case let memberAddedEvent as MemberAddedEvent:
+            var members = Set(channel?.lastActiveMembers ?? [])
+            members.insert(memberAddedEvent.member)
+            let memberCount = channel?.memberCount ?? 0
+
+            var membership: ChatChannelMember?
+            if memberAddedEvent.member.id == currentUserId {
+                membership = memberAddedEvent.member
+            }
+            channel = channel?.changing(
+                members: Array(members),
+                membership: membership,
+                memberCount: memberCount + 1
+            )
+
+        case let memberRemovedEvent as MemberRemovedEvent:
+            var members = channel?.lastActiveMembers ?? []
+            members.removeAll(where: { $0.id == memberRemovedEvent.user.id })
+            let memberCount = channel?.memberCount ?? 0
+
+            var membership: ChatChannelMember? = channel?.membership
+            if memberRemovedEvent.user.id == currentUserId {
+                membership = nil
+            }
+            channel = channel?.changing(members: members, memberCount: memberCount - 1)
+            channel?.membership = membership
+
+        case let userWatchingEvent as UserWatchingEvent:
+            var watchers = channel?.lastActiveWatchers ?? []
+            if userWatchingEvent.isStarted {
+                watchers.append(userWatchingEvent.user)
+            } else {
+                watchers.removeAll(where: { $0.id == userWatchingEvent.user.id })
+            }
+            channel = channel?.changing(watchers: watchers, watcherCount: userWatchingEvent.watcherCount)
+
+        case let memberUpdatedEvent as MemberUpdatedEvent:
+            var members = channel?.lastActiveMembers ?? []
+            if let index = members.firstIndex(where: { $0.id == memberUpdatedEvent.member.id }) {
+                members[index] = memberUpdatedEvent.member
+            }
+            
+            var membership: ChatChannelMember? = channel?.membership
+            if memberUpdatedEvent.member.id == currentUserId {
+                membership = memberUpdatedEvent.member
+            }
+            
+            channel = channel?.changing(members: members, membership: membership)
 
         case is UserBannedEvent,
              is UserUnbannedEvent:
@@ -1008,7 +1066,18 @@ public class LivestreamChannelController: DataStoreProvider, EventsControllerDel
 
     private func handleUpdatedMessage(_ updatedMessage: ChatMessage) {
         if let index = messages.firstIndex(where: { $0.id == updatedMessage.id }) {
+            let existingMessage = messages[index]
             messages[index] = updatedMessage
+
+            if existingMessage.isPinned != updatedMessage.isPinned {
+                var pinnedMessages = channel?.pinnedMessages ?? []
+                if updatedMessage.isPinned {
+                    pinnedMessages.append(updatedMessage)
+                } else {
+                    pinnedMessages.removeAll(where: { $0.id == existingMessage.id })
+                }
+                channel = channel?.changing(pinnedMessages: pinnedMessages)
+            }
         }
     }
 
@@ -1037,7 +1106,31 @@ public class LivestreamChannelController: DataStoreProvider, EventsControllerDel
     }
 
     private func handleChannelUpdated(_ event: ChannelUpdatedEvent) {
-        channel = event.channel
+        channel = channel?.changing(
+            name: event.channel.name,
+            imageURL: event.channel.imageURL,
+            lastMessageAt: event.channel.lastMessageAt,
+            createdAt: event.channel.createdAt,
+            deletedAt: event.channel.deletedAt,
+            updatedAt: event.channel.updatedAt,
+            truncatedAt: event.channel.truncatedAt,
+            isHidden: event.channel.isHidden,
+            createdBy: event.channel.createdBy,
+            config: event.channel.config,
+            ownCapabilities: event.channel.ownCapabilities,
+            isFrozen: event.channel.isFrozen,
+            isDisabled: event.channel.isDisabled,
+            isBlocked: event.channel.isBlocked,
+            reads: event.channel.reads,
+            members: event.channel.lastActiveMembers,
+            membership: event.channel.membership,
+            memberCount: event.channel.memberCount,
+            watchers: event.channel.lastActiveWatchers,
+            watcherCount: event.channel.watcherCount,
+            team: event.channel.team,
+            cooldownDuration: event.channel.cooldownDuration,
+            extraData: event.channel.extraData
+        )
     }
 
     // For events that do not have the channel data, and still

Sources/StreamChat/Models/Channel.swift

@@ -77,8 +77,8 @@ public struct ChatChannel {
     public let currentlyTypingUsers: Set<ChatUser>
 
     /// If the current user is a member of the channel, this variable contains the details about the membership.
-    public let membership: ChatChannelMember?
-    
+    public internal(set) var membership: ChatChannelMember?
+
     /// Returns `true`, if the channel is archived.
     public var isArchived: Bool {
         membership?.archivedAt != nil
@@ -293,39 +293,59 @@ public struct ChatChannel {
     public func changing(
         name: String? = nil,
         imageURL: URL? = nil,
+        lastMessageAt: Date? = nil,
+        createdAt: Date? = nil,
+        deletedAt: Date? = nil,
+        updatedAt: Date? = nil,
+        truncatedAt: Date? = nil,
+        isHidden: Bool? = nil,
+        createdBy: ChatUser? = nil,
+        config: ChannelConfig? = nil,
+        ownCapabilities: Set<ChannelCapability>? = nil,
+        isFrozen: Bool? = nil,
+        isDisabled: Bool? = nil,
+        isBlocked: Bool? = nil,
         reads: [ChatChannelRead]? = nil,
+        members: [ChatChannelMember]? = nil,
+        membership: ChatChannelMember? = nil,
+        memberCount: Int? = nil,
+        watchers: [ChatUser]? = nil,
+        watcherCount: Int? = nil,
+        team: TeamId? = nil,
+        cooldownDuration: Int? = nil,
+        pinnedMessages: [ChatMessage]? = nil,
         extraData: [String: RawJSON]? = nil
     ) -> ChatChannel {
         .init(
             cid: cid,
             name: name ?? self.name,
             imageURL: imageURL ?? self.imageURL,
-            lastMessageAt: lastMessageAt,
-            createdAt: createdAt,
-            updatedAt: updatedAt,
-            deletedAt: deletedAt,
-            truncatedAt: truncatedAt,
-            isHidden: isHidden,
-            createdBy: createdBy,
-            config: config,
-            ownCapabilities: ownCapabilities,
-            isFrozen: isFrozen,
-            isDisabled: isDisabled,
-            isBlocked: isBlocked,
-            lastActiveMembers: lastActiveMembers,
-            membership: membership,
+            lastMessageAt: lastMessageAt ?? self.lastMessageAt,
+            createdAt: createdAt ?? self.createdAt,
+            updatedAt: updatedAt ?? self.updatedAt,
+            deletedAt: deletedAt ?? self.deletedAt,
+            truncatedAt: truncatedAt ?? self.truncatedAt,
+            isHidden: isHidden ?? self.isHidden,
+            createdBy: createdBy ?? self.createdBy,
+            config: config ?? self.config,
+            ownCapabilities: ownCapabilities ?? self.ownCapabilities,
+            isFrozen: isFrozen ?? self.isFrozen,
+            isDisabled: isDisabled ?? self.isDisabled,
+            isBlocked: isBlocked ?? self.isBlocked,
+            lastActiveMembers: members ?? lastActiveMembers,
+            membership: membership ?? self.membership,
             currentlyTypingUsers: currentlyTypingUsers,
-            lastActiveWatchers: lastActiveWatchers,
-            team: team,
+            lastActiveWatchers: watchers ?? lastActiveWatchers,
+            team: team ?? self.team,
             unreadCount: unreadCount,
-            watcherCount: watcherCount,
-            memberCount: memberCount,
+            watcherCount: watcherCount ?? self.watcherCount,
+            memberCount: memberCount ?? self.memberCount,
             reads: reads ?? self.reads,
-            cooldownDuration: cooldownDuration,
-            extraData: extraData ?? [:],
+            cooldownDuration: cooldownDuration ?? self.cooldownDuration,
+            extraData: extraData ?? self.extraData,
             latestMessages: latestMessages,
             lastMessageFromCurrentUser: lastMessageFromCurrentUser,
-            pinnedMessages: pinnedMessages,
+            pinnedMessages: pinnedMessages ?? self.pinnedMessages,
             pendingMessages: pendingMessages,
             muteDetails: muteDetails,
             previewMessage: previewMessage,

Sources/StreamChat/Models/ChatMessage.swift

@@ -285,6 +285,7 @@ public struct ChatMessage {
         originalLanguage: TranslationLanguage? = nil,
         moderationDetails: MessageModerationDetails? = nil,
         readBy: Set<ChatUser>? = nil,
+        deletedAt: Date? = nil,
         extraData: [String: RawJSON]? = nil
     ) -> ChatMessage {
         .init(
@@ -296,7 +297,7 @@ public struct ChatMessage {
             createdAt: createdAt,
             locallyCreatedAt: locallyCreatedAt,
             updatedAt: updatedAt,
-            deletedAt: deletedAt,
+            deletedAt: deletedAt ?? self.deletedAt,
             arguments: arguments ?? self.arguments,
             parentMessageId: parentMessageId,
             showReplyInChannel: showReplyInChannel,