Channel was sometimes not selected if ChatChannelViewModel.selectedChannelId was set to a channel created a moments ago

Author: laevandus

CHANGELOG.md

@@ -7,6 +7,7 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/).
 - Rare crash when accessing frame of the view [#607](https://github.com/GetStream/stream-chat-swiftui/pull/607)
 - `ChatChannelListView` navigation did not trigger when using a custom container and its body reloaded [#609](https://github.com/GetStream/stream-chat-swiftui/pull/609)
 - Channel was sometimes not marked as read when tapping the x on the unread message pill in the message list [#610](https://github.com/GetStream/stream-chat-swiftui/pull/610)
+- Channel was sometimes not selected if `ChatChannelViewModel.selectedChannelId` was set to a channel created a moments ago [#611](https://github.com/GetStream/stream-chat-swiftui/pull/611)
 
 # [4.63.0](https://github.com/GetStream/stream-chat-swiftui/releases/tag/4.63.0)
 _September 12, 2024_

Sources/StreamChatSwiftUI/ChatChannelList/ChatChannelListViewModel.swift

@@ -53,6 +53,7 @@ open class ChatChannelListViewModel: ObservableObject, ChatChannelListController
             } else {
                 markDirty = false
             }
+            checkForDeeplinks()
         }
     }
 
@@ -117,7 +118,13 @@ open class ChatChannelListViewModel: ObservableObject, ChatChannelListController
     public var isSearching: Bool {
         !searchText.isEmpty
     }
-
+    
+    /// Creates a view model for the `ChatChannelListView`.
+    ///
+    /// - Parameters:
+    ///   - channelListController: A controller providing the list of channels. If nil, a controller with default `ChannelListQuery` is created.
+    ///   - selectedChannelId: The id of a channel to select. If the channel is not part of the channel list query, no channel is selected.
+    ///   Consider using ``ChatChannelScreen`` for presenting channels what might not be part of the initial page of channels.
     public init(
         channelListController: ChatChannelListController? = nil,
         selectedChannelId: String? = nil
@@ -265,15 +272,16 @@ open class ChatChannelListViewModel: ObservableObject, ChatChannelListController
         }
     }
 
+    /// Checks for currently loaded channels for opening a channel with id.
     private func checkForDeeplinks() {
-        if let selectedChannelId = selectedChannelId,
-           let channelId = try? ChannelId(cid: selectedChannelId) {
-            let chatController = chatClient.channelController(
-                for: channelId,
-                messageOrdering: .topToBottom
-            )
-            selectedChannel = chatController.channel?.channelSelectionInfo
+        guard let selectedChannelId else { return }
+        do {
+            let channelId = try ChannelId(cid: selectedChannelId)
+            guard let selectedChannel = channels.first(where: { $0.cid == channelId })?.channelSelectionInfo else { return }
             self.selectedChannelId = nil
+            self.selectedChannel = selectedChannel
+        } catch {
+            log.error("Failed to select a channel with id \(selectedChannelId) (\(error))")
         }
     }
 
@@ -307,7 +315,6 @@ open class ChatChannelListViewModel: ObservableObject, ChatChannelListController
                 if self.selectedChannel == nil {
                     self.updateChannels()
                 }
-                self.checkForDeeplinks()
             }
         }
     }

StreamChatSwiftUITests/Tests/ChatChannelList/ChatChannelListViewModel_Tests.swift

@@ -270,6 +270,55 @@ class ChatChannelListViewModel_Tests: StreamChatTestCase {
         // Then
         XCTAssert(viewModel.hideTabBar == true)
     }
+    
+    func test_channelListVM_deeplinkToExistingChannel() {
+        // Given
+        let channels = (0..<3).map { ChatChannel.mock(cid: ChannelId(type: .messaging, id: "\($0)")) }
+        let channelListController = makeChannelListController(channels: channels)
+        let selectedId = channels[1].cid
+        let viewModel = ChatChannelListViewModel(
+            channelListController: channelListController,
+            selectedChannelId: selectedId.rawValue
+        )
+        
+        // Then
+        let expectation = XCTestExpectation(description: "SelectedChannel")
+        let cancellable = viewModel.$selectedChannel
+            .filter { $0?.channel.cid == selectedId }
+            .sink { _ in
+                expectation.fulfill()
+            }
+        wait(for: [expectation], timeout: defaultTimeout)
+        cancellable.cancel()
+    }
+    
+    func test_channelListVM_deeplinkToIncomingChannel() {
+        // Given
+        let channels = (0..<3).map { ChatChannel.mock(cid: ChannelId(type: .messaging, id: "\($0)")) }
+        let channelListController = makeChannelListController(channels: channels)
+        let selectedId = ChannelId(type: .messaging, id: "3")
+        let viewModel = ChatChannelListViewModel(
+            channelListController: channelListController,
+            selectedChannelId: selectedId.rawValue
+        )
+        
+        // When
+        let expectation = XCTestExpectation(description: "SelectedChannel")
+        let cancellable = viewModel.$selectedChannel
+            .filter { $0?.channel.cid == selectedId }
+            .sink { _ in
+                expectation.fulfill()
+            }
+        let insertedChannel = ChatChannel.mock(cid: selectedId)
+        channelListController.simulate(
+            channels: channels + [insertedChannel],
+            changes: [.insert(insertedChannel, index: IndexPath(item: 0, section: 0))]
+        )
+        
+        // Then
+        wait(for: [expectation], timeout: defaultTimeout)
+        cancellable.cancel()
+    }
 
     // MARK: - private