Fix message thread reply footnote view not shown if parent message not in cache

CHANGELOG.md

@@ -3,6 +3,8 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/).
 
 # Upcoming
 
+### 🐞 Fixed
+- Fix message thread reply footnote view not shown if parent message not in cache [#681](https://github.com/GetStream/stream-chat-swiftui/pull/681)
 ### ⚡ Performance
 - Improve message search performance [#680](https://github.com/GetStream/stream-chat-swiftui/pull/680)
 

Sources/StreamChatSwiftUI/ChatChannel/MessageList/MessageContainerView.swift

@@ -185,6 +185,20 @@ public struct MessageContainerView<Factory: ViewFactory>: View {
                             )
                             .accessibilityElement(children: .contain)
                             .accessibility(identifier: "MessageRepliesView")
+                        } else if message.showReplyInChannel, let parentId = message.parentMessageId {
+                            /// In case the parent message is not available in the local cache, we need to fetch it from the remote server.
+                            /// The lazy view uses the `factory.makeMessageRepliesShownInChannelView` internally once the parent message is fetched.
+                            LazyMessageRepliesView(
+                                factory: factory,
+                                channel: channel,
+                                message: message,
+                                parentMessageController: chatClient.messageController(
+                                    cid: channel.cid,
+                                    messageId: parentId
+                                )
+                            )
+                            .accessibilityElement(children: .contain)
+                            .accessibility(identifier: "MessageRepliesView")
                         }
                     }
 

Sources/StreamChatSwiftUI/ChatChannel/MessageList/MessageRepliesView.swift

@@ -116,3 +116,45 @@ public struct MessageRepliesView<Factory: ViewFactory>: View {
         }
     }
 }
+
+/// Lazy view that uses the message controller to fetch the parent message before creating message replies view.
+/// This is needed when the parent message is not available in the local cache.
+/// Changing the `parentMessage` to `nil` in the `MessageRepliesView` would case multiple changes including breaking changes.
+struct LazyMessageRepliesView<Factory: ViewFactory>: View {
+    @StateObject private var parentMessageObserver: ChatMessageController.ObservableObject
+
+    var factory: Factory
+    var channel: ChatChannel
+    var message: ChatMessage
+
+    init(
+        factory: Factory,
+        channel: ChatChannel,
+        message: ChatMessage,
+        parentMessageController: ChatMessageController
+    ) {
+        _parentMessageObserver = StateObject(wrappedValue: parentMessageController.observableObject)
+        self.factory = factory
+        self.channel = channel
+        self.message = message
+    }
+
+    var body: some View {
+        VStack {
+            if let parentMessage = parentMessageObserver.message {
+                factory.makeMessageRepliesShownInChannelView(
+                    channel: channel,
+                    message: message,
+                    parentMessage: parentMessage,
+                    replyCount: parentMessage.replyCount
+                )
+            } else {
+                EmptyView()
+            }
+        }.onAppear {
+            if parentMessageObserver.message == nil {
+                parentMessageObserver.controller.synchronize()
+            }
+        }
+    }
+}