[CIS-1079] Fix CoreData misuse when creating Direct Messaging channels

CHANGELOG.md

@@ -21,6 +21,7 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/).
 - Fix compilation for Xcode 13 beta 3 where SDK could not compile because of unvailability of `UIApplication.shared` [#1333](https://github.com/GetStream/stream-chat-swift/pull/1333)
 - Fix member removed from a Channel is still present is MemberListController.members [#1323](https://github.com/GetStream/stream-chat-swift/issues/1323)
 - Fix composer input field height for long text [#1335](https://github.com/GetStream/stream-chat-swift/issues/1335)
+- Fix creating direct messaging channels creates CoreData misuse [#1337](https://github.com/GetStream/stream-chat-swift/issues/1337)
 
 ### 🔄 Changed
 - `ContainerStackView` doesn't `assert` when trying to remove a subview, these operations are now no-op [#1328](https://github.com/GetStream/stream-chat-swift/issues/1328)

Sources/StreamChat/Controllers/ChannelController/ChannelController.swift

@@ -309,15 +309,17 @@ public class _ChatChannelController<ExtraData: ExtraDataTypes>: DataController,
         _messagesObserver.computeValue = { [unowned self] in
             guard let cid = self.cid else { return nil }
             let sortAscending = self.listOrdering == .topToBottom ? false : true
-            let deletedMessageVisibility = self.client.databaseContainer.viewContext
-                .deletedMessagesVisibility ?? .visibleForCurrentUser
+            var deletedMessageVisibility: ChatClientConfig.DeletedMessageVisibility?
+            self.client.databaseContainer.viewContext.performAndWait {
+                deletedMessageVisibility = self.client.databaseContainer.viewContext.deletedMessagesVisibility
+            }
 
             let observer = ListDatabaseObserver(
                 context: self.client.databaseContainer.viewContext,
                 fetchRequest: MessageDTO.messagesFetchRequest(
                     for: cid,
                     sortAscending: sortAscending,
-                    deletedMessagesVisibility: deletedMessageVisibility
+                    deletedMessagesVisibility: deletedMessageVisibility ?? .visibleForCurrentUser
                 ),
                 itemCreator: { $0.asModel() as _ChatMessage<ExtraData> }
             )

Sources/StreamChat/Controllers/ChannelController/ChannelController_Tests.swift

@@ -378,8 +378,17 @@ class ChannelController_Tests: StressTestCase {
         try client.databaseContainer.writeSynchronously {
             try $0.saveChannel(payload: payload, query: nil)
         }
-        env.channelUpdater?.update_channelCreatedCallback?(channelId)
-        env.channelUpdater?.update_completion?(.success(dummyPayload(with: .unique)))
+
+        // We call these callbacks on a queue other than main queue
+        // to simulate the actual scenario where callbacks will be called
+        // from NSURLSession-delegate (serial) queue
+        let _: Bool = try waitFor { completion in
+            DispatchQueue.global().async {
+                self.env.channelUpdater?.update_channelCreatedCallback?(self.channelId)
+                self.env.channelUpdater?.update_completion?(.success(self.dummyPayload(with: .unique)))
+                completion(true)
+            }
+        }
 
         XCTAssertEqual(controller.channel?.cid, channelId)
         XCTAssertEqual(controller.messages.count, payload.messages.count)