[V5] Use Swift 6 with complete concurrency checking #902

laevandus · 2025-08-01T09:00:26Z

🔗 Issue Links

🎯 Goal

Use Swift 6 with strict concurrency checking set to complete

📝 Summary

Set Swift version to 6 with strict concurrency checking complete (including demo app)
Drop Xcode 15 support
Add Sendable conformances to public types
Add @mainactor to view models, view factory and view model factory
Nuke was upgraded from 10 to 12 (brings Swift 6 support)

🛠 Implementation

Tried to make it as concise as possible, therefore in some cases there is nonisolated(unsafe), because fixing them properly leads to huge refactoring (too large scope). In many cases this is actually all right.

🧪 Manual Testing Notes

Needs full regression testing round.

☑️ Contributor Checklist

I have signed the Stream CLA (required)
This change should be manually QAed
Changelog is updated with client-facing changes
Changelog is updated with new localization keys
New code is covered by unit tests
Documentation has been updated in the docs-content repo

github-actions · 2025-08-01T09:17:08Z

	1 Warning
⚠️	Big PR

	1 Message
📖	There seems to be app changes but CHANGELOG wasn't modified. Please include an entry if the PR includes user-facing changes. You can find it at CHANGELOG.md.

Generated by 🚫 Danger

github-actions · 2025-08-01T12:30:36Z

Public Interface

- public struct AddedVoiceRecording: Identifiable, Equatable  
+ public struct AddedVoiceRecording: Identifiable, Equatable, Sendable  

- public class ChatChannelInfoViewModel: ObservableObject, ChatChannelControllerDelegate  
+ @MainActor public class ChatChannelInfoViewModel: ObservableObject, ChatChannelControllerDelegate  
-   public func leaveConversationTapped(completion: @escaping () -> Void)
+   public func leaveConversationTapped(completion: @escaping @MainActor() -> Void)

 public struct AppearanceKey: EnvironmentKey  
-   public static let defaultValue: Appearance
+   public static var defaultValue: Appearance

- open class ChannelHeaderLoader: ObservableObject  
+ @MainActor open class ChannelHeaderLoader: ObservableObject  
-   public init()
+   nonisolated public init()

- public class PinnedMessagesViewModel: ObservableObject  
+ @MainActor public class PinnedMessagesViewModel: ObservableObject  

- public struct AddedAsset: Identifiable, Equatable  
+ public struct AddedAsset: Identifiable, Equatable, Sendable  

- public struct CustomAttachment: Identifiable, Equatable  
+ public struct CustomAttachment: Identifiable, Equatable, Sendable  

- public class PollAttachmentViewModel: ObservableObject, PollControllerDelegate  
+ @MainActor public class PollAttachmentViewModel: ObservableObject, PollControllerDelegate  

 public class InstantCommandsHandler: CommandHandler  
-   public func executeOnMessageSent(composerCommand: ComposerCommand,completion: @escaping (Error?) -> Void)
+   public func executeOnMessageSent(composerCommand: ComposerCommand,completion: @escaping @Sendable(Error?) -> Void)

- public class ChannelAvatarsMerger: ChannelAvatarsMerging  
+ public final class ChannelAvatarsMerger: ChannelAvatarsMerging  

- open class ChatChannelListViewModel: ObservableObject, ChatChannelListControllerDelegate, ChatMessageSearchControllerDelegate  
+ @MainActor open class ChatChannelListViewModel: ObservableObject, ChatChannelListControllerDelegate, ChatMessageSearchControllerDelegate  

- public struct ConfirmationPopup  
+ public struct ConfirmationPopup: Sendable  

- public protocol AudioSessionFeedbackGenerator
+ @MainActor public protocol AudioSessionFeedbackGenerator

- open class ReactionsOverlayViewModel: ObservableObject, ChatMessageControllerDelegate  
+ @MainActor open class ReactionsOverlayViewModel: ObservableObject, ChatMessageControllerDelegate  

- public struct PollsEntryConfig  
+ public struct PollsEntryConfig: Sendable  

 public class CommandsHandler: CommandHandler  
-   public func executeOnMessageSent(composerCommand: ComposerCommand,completion: @escaping (Error?) -> Void)
+   public func executeOnMessageSent(composerCommand: ComposerCommand,completion: @escaping @Sendable(Error?) -> Void)

- open class MessageActionsViewModel: ObservableObject  
+ @MainActor open class MessageActionsViewModel: ObservableObject  

- public struct PollsConfig  
+ public struct PollsConfig: Sendable  

- public struct PaddingsConfig  
+ public struct PaddingsConfig: Sendable  

- public enum StreamChatErrorCode: Int  
+ public enum StreamChatErrorCode: Int, Sendable  

- open class MoreChannelActionsViewModel: ObservableObject  
+ @MainActor open class MoreChannelActionsViewModel: ObservableObject  

 open class NukeImageLoader: ImageLoading  
-   open func loadImage(using urlRequest: URLRequest,cachingKey: String?,completion: @escaping ((Result<UIImage, Error>) -> Void))
+   open func loadImage(using urlRequest: URLRequest,cachingKey: String?,completion: @escaping @MainActor(Result<UIImage, Error>) -> Void)
-   open func loadImages(from urls: [URL],placeholders: [UIImage],loadThumbnails: Bool,thumbnailSize: CGSize,imageCDN: ImageCDN,completion: @escaping (([UIImage]) -> Void))
+   open func loadImages(from urls: [URL],placeholders: [UIImage],loadThumbnails: Bool,thumbnailSize: CGSize,imageCDN: ImageCDN,completion: @escaping @MainActor([UIImage]) -> Void)
-   open func loadImage(url: URL?,imageCDN: ImageCDN,resize: Bool = true,preferredSize: CGSize? = nil,completion: @escaping ((Result<UIImage, Error>) -> Void))
+   open func loadImage(url: URL?,imageCDN: ImageCDN,resize: Bool = true,preferredSize: CGSize? = nil,completion: @escaping @MainActor(Result<UIImage, Error>) -> Void)

- public class ViewModelsFactory  
+ @MainActor public class ViewModelsFactory  

 extension ChannelAction  
-   public static func defaultActions(for channel: ChatChannel,chatClient: ChatClient,onDismiss: @escaping () -> Void,onError: @escaping (Error) -> Void)-> [ChannelAction]
+   @MainActor public static func defaultActions(for channel: ChatChannel,chatClient: ChatClient,onDismiss: @escaping () -> Void,onError: @escaping (Error) -> Void)-> [ChannelAction]

- open class ChatThreadListViewModel: ObservableObject, ChatThreadListControllerDelegate, EventsControllerDelegate  
+ @MainActor open class ChatThreadListViewModel: ObservableObject, ChatThreadListControllerDelegate, EventsControllerDelegate  

 extension DateFormatter  
-   public static var messageListDateOverlay: DateFormatter
+   @MainActor public static var messageListDateOverlay: DateFormatter

- public struct InjectedChannelInfo  
+ public struct InjectedChannelInfo: Sendable  

 public struct StreamChatError: Error  
-   public let additionalInfo: [String: Any]?
+   public nonisolated let additionalInfo: [String: Any]?

- public protocol ChannelAvatarsMerging
+ public protocol ChannelAvatarsMerging: Sendable

- open class ChatChannelViewModel: ObservableObject, MessagesDataSource  
+ @MainActor open class ChatChannelViewModel: ObservableObject, MessagesDataSource  

 public class Appearance  
-   public static var localizationProvider: (_ key: String, _ table: String) -> String
+   nonisolated public static var localizationProvider: @Sendable(_ key: String, _ table: String) -> String

 extension CommandHandler  
-   public func executeOnMessageSent(composerCommand: ComposerCommand,completion: @escaping (Error?) -> Void)
+   public func executeOnMessageSent(composerCommand: ComposerCommand,completion: @escaping @Sendable(Error?) -> Void)

- public struct ChannelItemMutedLayoutStyle: Hashable  
+ public struct ChannelItemMutedLayoutStyle: Hashable, Sendable  
-   public static var `default`: ChannelItemMutedLayoutStyle
+   public static let `default`: ChannelItemMutedLayoutStyle
-   public static var topRightCorner: ChannelItemMutedLayoutStyle
+   public static let topRightCorner: ChannelItemMutedLayoutStyle
-   public static var afterChannelName: ChannelItemMutedLayoutStyle
+   public static let afterChannelName: ChannelItemMutedLayoutStyle

 public class Utils  
-   public lazy var audioSessionFeedbackGenerator: AudioSessionFeedbackGenerator
+   @MainActor public lazy var audioSessionFeedbackGenerator: AudioSessionFeedbackGenerator

 open class WaveformView: UIView  
-   public struct Content: Equatable  
+   public struct Content: Equatable, Sendable  

- public struct ChannelListSearchType: Equatable  
+ public struct ChannelListSearchType: Equatable, Sendable  
-   public static var channels
+   public static let channels
-   public static var messages
+   public static let messages

 public class UnmuteCommandHandler: TwoStepMentionCommand  
-   override public func executeOnMessageSent(composerCommand: ComposerCommand,completion: @escaping (Error?) -> Void)
+   override public func executeOnMessageSent(composerCommand: ComposerCommand,completion: @escaping @Sendable(Error?) -> Void)

 public final class DefaultVideoPreviewLoader: VideoPreviewLoader  
-   public func loadPreviewForVideo(at url: URL,completion: @escaping (Result<UIImage, Error>) -> Void)
+   public func loadPreviewForVideo(at url: URL,completion: @escaping @MainActor(Result<UIImage, Error>) -> Void)

 open class StreamImageCDN: ImageCDN  
-   public static var streamCDNURL
+   public static let streamCDNURL

- open class MessageViewModel: ObservableObject  
+ @MainActor open class MessageViewModel: ObservableObject  

- public struct ChannelSelectionInfo: Identifiable  
+ public struct ChannelSelectionInfo: Identifiable, Sendable  

- public enum AssetType  
+ public enum AssetType: Sendable  

- open class MessageComposerViewModel: ObservableObject  
+ @MainActor open class MessageComposerViewModel: ObservableObject  
-   open func sendMessage(quotedMessage: ChatMessage?,editedMessage: ChatMessage?,isSilent: Bool = false,skipPush: Bool = false,skipEnrichUrl: Bool = false,extraData: [String: RawJSON] = [:],completion: @escaping () -> Void)
+   open func sendMessage(quotedMessage: ChatMessage?,editedMessage: ChatMessage?,isSilent: Bool = false,skipPush: Bool = false,skipEnrichUrl: Bool = false,extraData: [String: RawJSON] = [:],completion: @escaping @MainActor() -> Void)

- public struct MessageActionInfo  
+ public struct MessageActionInfo: Sendable  

 open class TwoStepMentionCommand: CommandHandler  
-   open func executeOnMessageSent(composerCommand: ComposerCommand,completion: @escaping (Error?) -> Void)
+   open func executeOnMessageSent(composerCommand: ComposerCommand,completion: @escaping @Sendable(Error?) -> Void)

 public class MuteCommandHandler: TwoStepMentionCommand  
-   override public func executeOnMessageSent(composerCommand: ComposerCommand,completion: @escaping (Error?) -> Void)
+   override public func executeOnMessageSent(composerCommand: ComposerCommand,completion: @escaping @Sendable(Error?) -> Void)

- public struct AudioRecordingInfo: Equatable  
+ public struct AudioRecordingInfo: Equatable, Sendable  

- public struct ChannelAction: Identifiable  
+ public struct ChannelAction: Identifiable, @unchecked Sendable  
-   public var navigationDestination: AnyView?
+   nonisolated public var navigationDestination: AnyView?

 public struct ComposerConfig  
-   public static var defaultAttachmentPayloadConverter: (ChatMessage) -> [AnyAttachmentPayload]
+   nonisolated public static var defaultAttachmentPayloadConverter: (ChatMessage) -> [AnyAttachmentPayload]

- public protocol CommandHandler
+ @MainActor public protocol CommandHandler

- public struct TypingSuggestion  
+ public struct TypingSuggestion: Sendable  

- public protocol ViewFactory: AnyObject
+ @MainActor public protocol ViewFactory: AnyObject

laevandus · 2025-08-01T12:31:21Z

.swiftlint.yml

@@ -43,14 +43,10 @@ only_rules:
  - trailing_comma
  - trailing_newline
  - trailing_semicolon
-  - trailing_whitespace


This was breaking markdown tests which only happened in this PR because I did a change in MessageView_Test.swift which then led linter to lint the whole file and apply fixes. Some tests need soft linebreak which is (double space)

Stream-SDK-Bot · 2025-08-04T06:33:41Z

SDK Size

`title`	`develop`	`branch`	`diff`	`status`
StreamChatSwiftUI	9.22 MB	9.4 MB	+181 KB	🟢

laevandus · 2025-08-04T07:00:50Z

Sources/StreamChatSwiftUI/StreamNuke/Nuke/Caching/DataCache.swift

@@ -1,6 +1,6 @@
 // The MIT License (MIT)


Do not review anything under StreamNuke, skip it

Maybe we should consider removing it? We don't have gifs from here, and we might consider using AsyncImage wrapper?

Not in the scope of this PR though

If there is some time to do it in v5, we should. I'll add a ticket for that to the v5 list.

martinmitrevski

We have a bit more work here - we need to update the InjectedValues to make its usage better, plus we should think about the external dependencies.

martinmitrevski · 2025-08-04T11:45:50Z

DemoAppSwiftUI/NotificationsHandler.swift

-                token: token,
-                cid: cid
-            )
+        Task { @MainActor in


We should have some consistency in how we run things on the main thread. On the other PR this was done with an abstraction.

Since this piece is not part of the SDK and part of the demo app, I did not want to duplicate here. So demo app uses Task, SDK uses that abstraction (mostly)

martinmitrevski · 2025-08-04T11:51:19Z

Sources/StreamChatSwiftUI/ChatChannel/MessageList/ReactionsIconProvider.swift

@@ -19,7 +18,9 @@ class ReactionsIconProvider {

    static func color(for reaction: MessageReactionType, userReactionIDs: Set<MessageReactionType>) -> Color? {
        let containsUserReaction = userReactionIDs.contains(reaction)
-        let color = containsUserReaction ? colors.reactionCurrentUserColor : colors.reactionOtherUserColor
+        let color = containsUserReaction ?
+            InjectedValues[\.colors].reactionCurrentUserColor :


We should probably update the InjectedValues mechanism, using it like this kind of defeats its purpose.

I see, the issue here is that colors is static var here and it has mutable properties so compiler is:
Static property 'colors' is not concurrency-safe because it is nonisolated global shared mutable state
On the second look, all of this should be MainActor. Let me see.

Ah yeah, I'll revert and just make some things here @mainactor.

Done, avoids this change

martinmitrevski · 2025-08-04T11:52:14Z

Sources/StreamChatSwiftUI/ChatChannelList/ChannelAvatarsMerger.swift

    public init() {
        // Public init.
    }

-    @Injected(\.utils) private var utils
-    @Injected(\.images) private var images
+    private var images: Images { InjectedValues[\.images] }


Same here, we should definitely do sth about this.

The case here is that ChannelAvatarsMerger is called from background threads. @injected properties have mutable state and therefore must be concurrency safe. @injected is not, InjectedValues is internally nonisolated(unsafe) which makes the compiler happy. Alternative approach would be to pass Images and Utils in with the initialiser.

martinmitrevski · 2025-08-04T11:52:38Z

Sources/StreamChatSwiftUI/ChatChannelList/ChannelHeaderLoader.swift

@@ -36,7 +36,7 @@ open class ChannelHeaderLoader: ObservableObject {
    private var loadedImages = [ChannelId: UIImage]()
    private let didLoadImage = PassthroughSubject<ChannelId, Never>()

-    public init() {
+    nonisolated public init() {


Why nonisolated?

Utils creates this class in its init method, but Utils does not force MainActor. It is slightly bigger change because Utils is used in model objects (ChatChannel) what is Sendable. It is going to have bigger side-effects (all the callsites must ensure MainActor). Now the question is, should we try to make Utils @mainactor, maybe, but probably makes sense to have it in a separate ticket.

If Utils is MainActor, then the high-level StreamChat must become MainActor as well.

For now I took a shortcut here.

martinmitrevski · 2025-08-04T11:54:31Z

Sources/StreamChatSwiftUI/StreamNuke/Nuke/Caching/DataCache.swift

@@ -1,6 +1,6 @@
 // The MIT License (MIT)


Maybe we should consider removing it? We don't have gifs from here, and we might consider using AsyncImage wrapper?

martinmitrevski · 2025-08-04T11:54:44Z

Sources/StreamChatSwiftUI/StreamNuke/Nuke/Caching/DataCache.swift

@@ -1,6 +1,6 @@
 // The MIT License (MIT)


Not in the scope of this PR though

martinmitrevski · 2025-08-04T11:58:02Z

Sources/StreamChatSwiftUI/Utils/StreamConcurrency.swift

+
+import Foundation
+
+enum StreamConcurrency {


We should move this to Core maybe?

I'll add a note to consider it to the ticket we have about adding Stream Core to chat.

sonarqubecloud · 2025-08-21T10:06:52Z

Quality Gate failed

Failed conditions
45.6% Coverage on New Code (required ≥ 80%)

See analysis details on SonarQube Cloud

nuno-vieira · 2025-08-21T14:16:32Z

...StreamChatSwiftUI/ChatChannel/Composer/Suggestions/InstantCommands/InstantCommandsView.swift

+                                    StreamConcurrency.onMain {
+                                        if let value = value, value != itemHeight {
+                                            itemHeight = value
+                                        }


If we make the view MainActor, doesn't it fix this? Kinda weird that we need to do this in a View, which can only be used on the main thread either way 🤔

nuno-vieira · 2025-08-21T14:22:44Z

Sources/StreamChatSwiftUI/ChatChannel/ChatChannelViewModel.swift

+        StreamConcurrency.onMain {
+            messageCachingUtils.clearCache()
+            if messageController == nil {
+                utils.channelControllerFactory.clearCurrentController()
+                cleanupAudioPlayer()
+                ImageCache.shared.trim(toCost: utils.messageListConfig.cacheSizeOnChatDismiss)
+                if !channelDataSource.hasLoadedAllNextMessages {
+                    channelDataSource.loadFirstPage { _ in }
+                }


If the view model is MainActor, why do we need to use StreamConcurrency.onMain here? 🤔

nuno-vieira · 2025-08-21T14:34:59Z

Sources/StreamChatSwiftUI/ChatChannelList/DefaultChannelActions.swift

+        nonisolated(unsafe) let unsafeOnDismiss = onDismiss
+        nonisolated(unsafe) let unsafeOnError = onError


Why is this needed? Aren't the completion blocks MainActor?

nuno-vieira · 2025-08-21T14:35:20Z

Sources/StreamChatSwiftUI/ChatChannelList/DefaultChannelActions.swift

+        nonisolated(unsafe) let unsafeOnDismiss = onDismiss
+        nonisolated(unsafe) let unsafeOnError = onError


Can we make the completion blocks main actor?

laevandus added 2 commits August 1, 2025 11:38

Use Swift 6 with complete concurrency checking

5e23ec4

Use Swift 6 with complete concurrency checking

13c55ed

laevandus requested a review from a team as a code owner August 1, 2025 09:00

laevandus added 🤞 Ready for QA 🪧 Demo App An Issue or PR related to the Demo App ✅ Feature An issue or PR related to a feature labels Aug 1, 2025

laevandus marked this pull request as draft August 1, 2025 09:00

laevandus added the 💥 Breaking Changes A PR that contains breaking changes label Aug 1, 2025

laevandus added 3 commits August 1, 2025 12:50

Fix tests

cc74a84

Update CoreData model for SwiftUI tests

76925c1

Revert removed newlines in tests

fd83af7

laevandus commented Aug 1, 2025

View reviewed changes

Merge branch 'v5' into swift-6-simplified

9b980e2

laevandus commented Aug 4, 2025

View reviewed changes

laevandus marked this pull request as ready for review August 4, 2025 08:16

martinmitrevski reviewed Aug 4, 2025

View reviewed changes

Xcode 16.2 compatibility

4de3548

GetStream deleted a comment from github-actions bot Aug 4, 2025

laevandus added 3 commits August 4, 2025 16:08

Use @mainactor in ReactionsIconProvider

1365a41

Merge branch 'v5' into swift-6-simplified

6872bde

Drop Sendable from MainActor closures

6f256e4

GetStream deleted a comment from github-actions bot Aug 21, 2025

nuno-vieira reviewed Aug 21, 2025

View reviewed changes

		nonisolated(unsafe) let unsafeOnDismiss = onDismiss
		nonisolated(unsafe) let unsafeOnError = onError

[V5] Use Swift 6 with complete concurrency checking #902

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[V5] Use Swift 6 with complete concurrency checking #902

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laevandus commented Aug 1, 2025

🔗 Issue Links

🎯 Goal

📝 Summary

🛠 Implementation

🧪 Manual Testing Notes

☑️ Contributor Checklist

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github-actions bot commented Aug 1, 2025 •

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