Disable strict concurrency checking

# Conflicts:
#	Tusker/Caching/ImageCache.swift
#	Tusker/Extensions/PKDrawing+Render.swift
#	Tusker/MultiThreadDictionary.swift
#	Tusker/Views/BaseEmojiLabel.swift

OpenInTusker/ActionViewController.swift

@@ -18,19 +18,23 @@ class ActionViewController: UIViewController {
         super.viewDidLoad()
         
         findURLFromWebPage { (components) in
-            if let components = components {
-                self.searchForURLInApp(components)
-            } else {
-                self.findURLItem { (components) in
-                    if let components = components {
-                        self.searchForURLInApp(components)
+            DispatchQueue.main.async {
+                if let components {
+                    self.searchForURLInApp(components)
+                } else {
+                    self.findURLItem { (components) in
+                        if let components {
+                            DispatchQueue.main.async {
+                                self.searchForURLInApp(components)
+                            }
+                        }
                     }
                 }
             }
         }
     }
     
-    private func findURLFromWebPage(completion: @escaping (URLComponents?) -> Void) {
+    private func findURLFromWebPage(completion: @escaping @Sendable (URLComponents?) -> Void) {
         for item in extensionContext!.inputItems as! [NSExtensionItem] {
             for provider in item.attachments! {
                 guard provider.hasItemConformingToTypeIdentifier(UTType.propertyList.identifier) else {
@@ -54,7 +58,7 @@ class ActionViewController: UIViewController {
         completion(nil)
     }
     
-    private func findURLItem(completion: @escaping (URLComponents?) -> Void) {
+    private func findURLItem(completion: @escaping @Sendable (URLComponents?) -> Void) {
         for item in extensionContext!.inputItems as! [NSExtensionItem] {
             for provider in item.attachments! {
                 guard provider.hasItemConformingToTypeIdentifier(UTType.url.identifier) else {

Packages/ComposeUI/Sources/ComposeUI/ComposeMastodonContext.swift

@@ -15,7 +15,8 @@ public protocol ComposeMastodonContext {
     var instanceFeatures: InstanceFeatures { get }
     
     func run<Result: Sendable>(_ request: Request<Result>) async throws -> (Result, Pagination?)
-    func getCustomEmojis(completion: @escaping ([Emoji]) -> Void)
+    
+    func getCustomEmojis() async -> [Emoji]
     
     @MainActor
     func searchCachedAccounts(query: String) -> [AccountProtocol]

Packages/ComposeUI/Sources/ComposeUI/Controllers/AutocompleteEmojisController.swift

@@ -44,11 +44,7 @@ class AutocompleteEmojisController: ViewController {
     
     @MainActor
     private func queryChanged(_ query: String) async {
-        var emojis = await withCheckedContinuation { continuation in
-            composeController.mastodonController.getCustomEmojis {
-                continuation.resume(returning: $0)
-            }
-        }
+        var emojis = await composeController.mastodonController.getCustomEmojis()
         guard !Task.isCancelled else {
             return
         }

Packages/Duckable/Sources/Duckable/API.swift

@@ -7,6 +7,7 @@
 
 import UIKit
 
+@MainActor
 public protocol DuckableViewController: UIViewController {
     func duckableViewControllerShouldDuck() -> DuckAttemptAction
     

Packages/InstanceFeatures/Sources/InstanceFeatures/InstanceFeatures.swift

@@ -10,7 +10,7 @@ import Foundation
 import Combine
 import Pachyderm
 
-public class InstanceFeatures: ObservableObject {
+public final class InstanceFeatures: ObservableObject {
     private static let pleromaVersionRegex = try! NSRegularExpression(pattern: "\\(compatible; (pleroma|akkoma) (.*)\\)", options: .caseInsensitive)
     
     private let _featuresUpdated = PassthroughSubject<Void, Never>()

Packages/Pachyderm/Sources/Pachyderm/Client.swift

@@ -12,7 +12,7 @@ import WebURL
 /**
  The base Mastodon API client.
  */
-public class Client {
+public struct Client: Sendable {
     
     public typealias Callback<Result: Decodable> = (Response<Result>) -> Void
     
@@ -20,8 +20,6 @@ public class Client {
     let session: URLSession
     
     public var accessToken: String?
-    
-    public var appID: String?
     public var clientID: String?
     public var clientSecret: String?
     
@@ -61,9 +59,11 @@ public class Client {
         return encoder
     }()
     
-    public init(baseURL: URL, accessToken: String? = nil, session: URLSession = .shared) {
+    public init(baseURL: URL, accessToken: String? = nil, clientID: String? = nil, clientSecret: String? = nil, session: URLSession = .shared) {
         self.baseURL = baseURL
         self.accessToken = accessToken
+        self.clientID = clientID
+        self.clientSecret = clientSecret
         self.session = session
     }
     
@@ -150,14 +150,7 @@ public class Client {
                 "scopes" => scopes.scopeString,
                 "website" => website?.absoluteString
             ]))
-        run(request) { result in
-            defer { completion(result) }
-            guard case let .success(application, _) = result else { return }
-            
-            self.appID = application.id
-            self.clientID = application.clientID
-            self.clientSecret = application.clientSecret
-        }
+        run(request, completion: completion)
     }
     
     public func getAccessToken(authorizationCode: String, redirectURI: String, scopes: [Scope], completion: @escaping Callback<LoginSettings>) {
@@ -169,12 +162,7 @@ public class Client {
                 "redirect_uri" => redirectURI,
                 "scope" => scopes.scopeString,
             ]))
-        run(request) { result in
-            defer { completion(result) }
-            guard case let .success(loginSettings, _) = result else { return }
-            
-            self.accessToken = loginSettings.accessToken
-        }
+        run(request, completion: completion)
     }
     
     public func revokeAccessToken() async throws {
@@ -198,21 +186,16 @@ public class Client {
         })
     }
     
-    public func nodeInfo(completion: @escaping Callback<NodeInfo>) {
+    public func nodeInfo() async throws -> NodeInfo {
         let wellKnown = Request<WellKnown>(method: .get, path: "/.well-known/nodeinfo")
-        run(wellKnown) { result in
-            switch result {
-            case let .failure(error):
-                completion(.failure(error))
-                
-            case let .success(wellKnown, _):
-                if let url = wellKnown.links.first(where: { $0.rel == "http://nodeinfo.diaspora.software/ns/schema/2.0" }),
-                   let href = WebURL(url.href),
-                   href.host == WebURL(self.baseURL)?.host {
-                    let nodeInfo = Request<NodeInfo>(method: .get, path: Endpoint(stringLiteral: href.path))
-                    self.run(nodeInfo, completion: completion)
-                }
-            }
+        let wellKnownResults = try await run(wellKnown).0
+        if let url = wellKnownResults.links.first(where: { $0.rel == "http://nodeinfo.diaspora.software/ns/schema/2.0" }),
+           let href = WebURL(url.href),
+           href.host == WebURL(self.baseURL)?.host {
+            let nodeInfo = Request<NodeInfo>(method: .get, path: Endpoint(stringLiteral: href.path))
+            return try await run(nodeInfo).0
+        } else {
+            throw NodeInfoError.noWellKnownLink
         }
     }
     
@@ -600,4 +583,15 @@ extension Client {
         case invalidModel(Swift.Error)
         case mastodonError(Int, String)
     }
+    
+    enum NodeInfoError: LocalizedError {
+        case noWellKnownLink
+        
+        var errorDescription: String? {
+            switch self {
+            case .noWellKnownLink:
+                return "No well-known link"
+            }
+        }
+    }
 }

Packages/Pachyderm/Sources/Pachyderm/Model/SearchOperatorType.swift

@@ -7,7 +7,7 @@
 
 import Foundation
 
-public enum SearchOperatorType: String, CaseIterable, Equatable {
+public enum SearchOperatorType: String, CaseIterable, Equatable, Sendable {
     case has
     case `is`
     case language

Packages/Pachyderm/Sources/Pachyderm/Model/StatusEdit.swift

@@ -7,7 +7,7 @@
 
 import Foundation
 
-public struct StatusEdit: Decodable {
+public struct StatusEdit: Decodable, Sendable {
     public let content: String
     public let spoilerText: String
     public let sensitive: Bool
@@ -28,10 +28,10 @@ public struct StatusEdit: Decodable {
         case emojis
     }
     
-    public struct Poll: Decodable {
+    public struct Poll: Decodable, Sendable {
         public let options: [Option]
         
-        public struct Option: Decodable {
+        public struct Option: Decodable, Sendable {
             public let title: String
         }
     }

Packages/Pachyderm/Sources/Pachyderm/Model/StatusSource.swift

@@ -7,7 +7,7 @@
 
 import Foundation
 
-public struct StatusSource: Decodable {
+public struct StatusSource: Decodable, Sendable {
     public let id: String
     public let text: String
     public let spoilerText: String

Packages/Pachyderm/Sources/Pachyderm/Utilities/InstanceSelector.swift

@@ -49,7 +49,7 @@ public class InstanceSelector {
 }
 
 public extension InstanceSelector {
-    struct Instance: Codable {
+    struct Instance: Codable, Sendable {
         public let domain: String
         public let description: String
         public let proxiedThumbnailURL: URL

Packages/TuskerPreferences/Sources/TuskerPreferences/PostVisibility.swift

@@ -8,7 +8,7 @@
 import Foundation
 import Pachyderm
 
-public enum PostVisibility: Codable, Hashable, CaseIterable {
+public enum PostVisibility: Codable, Hashable, CaseIterable, Sendable {
     case serverDefault
     case visibility(Visibility)
     
@@ -59,6 +59,7 @@ public enum ReplyVisibility: Codable, Hashable, CaseIterable {
     
     public static var allCases: [ReplyVisibility] = [.sameAsPost] + Visibility.allCases.map { .visibility($0) }
     
+    @MainActor
     public func resolved(withServerDefault serverDefault: Visibility?) -> Visibility {
         switch self {
         case .sameAsPost:

Packages/TuskerPreferences/Sources/TuskerPreferences/Preferences.swift

@@ -12,12 +12,14 @@ import Combine
 
 public final class Preferences: Codable, ObservableObject {
 
+    @MainActor
     public static var shared: Preferences = load()
     
     private static var documentsDirectory = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask).first!
     private static var appGroupDirectory = FileManager.default.containerURL(forSecurityApplicationGroupIdentifier: "group.space.vaccor.Tusker")!
     private static var archiveURL = appGroupDirectory.appendingPathComponent("preferences").appendingPathExtension("plist")
     
+    @MainActor
     public static func save() {
         let encoder = PropertyListEncoder()
         let data = try? encoder.encode(shared)
@@ -33,6 +35,7 @@ public final class Preferences: Codable, ObservableObject {
         return Preferences()
     }
     
+    @MainActor
     public static func migrate(from url: URL) -> Result<Void, any Error> {
         do {
             try? FileManager.default.removeItem(at: archiveURL)

Packages/TuskerPreferences/Sources/TuskerPreferences/StatusSwipeAction.swift

@@ -9,7 +9,7 @@
 import UIKit
 import Pachyderm
 
-public enum StatusSwipeAction: String, Codable, Hashable, CaseIterable {
+public enum StatusSwipeAction: String, Codable, Hashable, CaseIterable, Sendable {
     case reply
     case favorite
     case reblog

Packages/UserAccounts/Sources/UserAccounts/UserAccountInfo.swift

@@ -8,7 +8,7 @@
 import Foundation
 import CryptoKit
 
-public struct UserAccountInfo: Equatable, Hashable, Identifiable {
+public struct UserAccountInfo: Equatable, Hashable, Identifiable, Sendable {
     public let id: String
     public let instanceURL: URL
     public let clientID: String

ShareExtension/ShareHostingController.swift

@@ -132,7 +132,7 @@ extension UIColor {
             return .systemBackground
         }
     }
-    
+
     static let appGroupedBackground = UIColor { traitCollection in
         if case .dark = traitCollection.userInterfaceStyle,
            !Preferences.shared.pureBlackDarkMode {

ShareExtension/ShareMastodonContext.swift

@@ -12,7 +12,7 @@ import UserAccounts
 import InstanceFeatures
 import Combine
 
-class ShareMastodonContext: ComposeMastodonContext, ObservableObject {
+final class ShareMastodonContext: ComposeMastodonContext, ObservableObject, Sendable {
     let accountInfo: UserAccountInfo?
     let client: Client
     let instanceFeatures: InstanceFeatures
@@ -20,7 +20,9 @@ class ShareMastodonContext: ComposeMastodonContext, ObservableObject {
     @MainActor
     private var customEmojis: [Emoji]?
     
-    @Published var ownAccount: Account?
+    @MainActor
+    @Published
+    private(set) var ownAccount: Account?
     
     init(accountInfo: UserAccountInfo) {
         self.accountInfo = accountInfo
@@ -29,16 +31,7 @@ class ShareMastodonContext: ComposeMastodonContext, ObservableObject {
         
         Task { @MainActor in
             async let instance = try? await run(Client.getInstanceV1()).0
-            async let nodeInfo: NodeInfo? = await withCheckedContinuation({ continuation in
-                self.client.nodeInfo { response in
-                    switch response {
-                    case .success(let nodeInfo, _):
-                        continuation.resume(returning: nodeInfo)
-                    case .failure(_):
-                        continuation.resume(returning: nil)
-                    }
-                }
-            })
+            async let nodeInfo = try? await client.nodeInfo()
             guard let instance = await instance else { return }
             self.instanceFeatures.update(instance: InstanceInfo(v1: instance), nodeInfo: await nodeInfo)
         }
@@ -66,15 +59,13 @@ class ShareMastodonContext: ComposeMastodonContext, ObservableObject {
     }
     
     @MainActor
-    func getCustomEmojis(completion: @escaping ([Emoji]) -> Void) {
+    func getCustomEmojis() async -> [Emoji] {
         if let customEmojis {
-            completion(customEmojis)
+            return customEmojis
         } else {
-            Task.detached { @MainActor in
-                let emojis = (try? await self.run(Client.getCustomEmoji()).0) ?? []
-                self.customEmojis = emojis
-                completion(emojis)
-            }
+            let emojis = (try? await self.run(Client.getCustomEmoji()).0) ?? []
+            self.customEmojis = emojis
+            return emojis
         }
     }
     

ShareExtension/SwitchAccountContainerView.swift

@@ -54,6 +54,7 @@ struct SwitchAccountContainerView: View {
     }
 }
 
+@MainActor
 private struct AccountButtonLabel: View {
     static let urlSession = URLSession(configuration: .ephemeral)
     

Tusker.xcodeproj/project.pbxproj

@@ -314,6 +314,7 @@
 		D6DD8FFD298495A8002AD3FD /* LogoutService.swift in Sources */ = {isa = PBXBuildFile; fileRef = D6DD8FFC298495A8002AD3FD /* LogoutService.swift */; };
 		D6DD8FFF2984D327002AD3FD /* BookmarksViewController.swift in Sources */ = {isa = PBXBuildFile; fileRef = D6DD8FFE2984D327002AD3FD /* BookmarksViewController.swift */; };
 		D6DD996B2998611A0015C962 /* SuggestedProfilesViewController.swift in Sources */ = {isa = PBXBuildFile; fileRef = D6DD996A2998611A0015C962 /* SuggestedProfilesViewController.swift */; };
+		D6DEBA8D2B6579830008629A /* MainThreadBox.swift in Sources */ = {isa = PBXBuildFile; fileRef = D6DEBA8C2B6579830008629A /* MainThreadBox.swift */; };
 		D6DF95C12533F5DE0027A9B6 /* RelationshipMO.swift in Sources */ = {isa = PBXBuildFile; fileRef = D6DF95C02533F5DE0027A9B6 /* RelationshipMO.swift */; };
 		D6DFC69E242C490400ACC392 /* TrackpadScrollGestureRecognizer.swift in Sources */ = {isa = PBXBuildFile; fileRef = D6DFC69D242C490400ACC392 /* TrackpadScrollGestureRecognizer.swift */; };
 		D6DFC6A0242C4CCC00ACC392 /* Weak.swift in Sources */ = {isa = PBXBuildFile; fileRef = D6DFC69F242C4CCC00ACC392 /* Weak.swift */; };
@@ -722,6 +723,7 @@
 		D6DD8FFC298495A8002AD3FD /* LogoutService.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = LogoutService.swift; sourceTree = "<group>"; };
 		D6DD8FFE2984D327002AD3FD /* BookmarksViewController.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = BookmarksViewController.swift; sourceTree = "<group>"; };
 		D6DD996A2998611A0015C962 /* SuggestedProfilesViewController.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = SuggestedProfilesViewController.swift; sourceTree = "<group>"; };
+		D6DEBA8C2B6579830008629A /* MainThreadBox.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = MainThreadBox.swift; sourceTree = "<group>"; };
 		D6DF95C02533F5DE0027A9B6 /* RelationshipMO.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = RelationshipMO.swift; sourceTree = "<group>"; };
 		D6DFC69D242C490400ACC392 /* TrackpadScrollGestureRecognizer.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = TrackpadScrollGestureRecognizer.swift; sourceTree = "<group>"; };
 		D6DFC69F242C4CCC00ACC392 /* Weak.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = Weak.swift; sourceTree = "<group>"; };
@@ -1502,6 +1504,7 @@
 				D61F75BC293D099600C0B37F /* Lazy.swift */,
 				D60E2F2B24423EAD005F8713 /* LazilyDecoding.swift */,
 				D61DC84528F498F200B82C6E /* Logging.swift */,
+				D6DEBA8C2B6579830008629A /* MainThreadBox.swift */,
 				D6B81F432560390300F6E31D /* MenuController.swift */,
 				D6CF5B842AC7C56F00F15D83 /* MultiColumnCollectionViewLayout.swift */,
 				D64D8CA82463B494006B0BAA /* MultiThreadDictionary.swift */,
@@ -2149,6 +2152,7 @@
 				D601FA61297B539E00A8E8B5 /* ConversationMainStatusCollectionViewCell.swift in Sources */,
 				D67C57AD21E265FC00C3118B /* LargeAccountDetailView.swift in Sources */,
 				D601FA5F297B339100A8E8B5 /* ExpandThreadCollectionViewCell.swift in Sources */,
+				D6DEBA8D2B6579830008629A /* MainThreadBox.swift in Sources */,
 				D6262C9A28D01C4B00390C1F /* LoadingTableViewCell.swift in Sources */,
 				D68C2AE325869BAB00548EFF /* AuxiliarySceneDelegate.swift in Sources */,
 				D6D706A72948D4D0000827ED /* TimlineState.swift in Sources */,

Tusker/API/MastodonController.swift

@@ -15,16 +15,16 @@ import InstanceFeatures
 import Sentry
 #endif
 import ComposeUI
+import OSLog
 
 private let oauthScopes = [Scope.read, .write, .follow]
+private let logger = Logger(subsystem: Bundle.main.bundleIdentifier!, category: "MastodonController")
 
-class MastodonController: ObservableObject {
+final class MastodonController: ObservableObject, Sendable {
 
+    @MainActor
     static private(set) var all = [UserAccountInfo: MastodonController]()
     
-    @available(*, message: "do something less dumb")
-    static var first: MastodonController { all.first!.value }
-    
     @MainActor
     static func getForAccount(_ account: UserAccountInfo) -> MastodonController {
         if let controller = all[account] {
@@ -36,10 +36,12 @@ class MastodonController: ObservableObject {
         }
     }
     
+    @MainActor
     static func removeForAccount(_ account: UserAccountInfo) {
         all.removeValue(forKey: account)
     }
     
+    @MainActor
     static func resetAll() {
         all = [:]
     }
@@ -48,26 +50,31 @@ class MastodonController: ObservableObject {
     nonisolated let persistentContainer: MastodonCachePersistentStore// = MastodonCachePersistentStore(for: accountInfo, transient: transient)
 
     let instanceURL: URL
-    var accountInfo: UserAccountInfo?
-    var accountPreferences: AccountPreferences!
+    let accountInfo: UserAccountInfo?
+    @MainActor
+    private(set) var accountPreferences: AccountPreferences!
     
-    let client: Client!
+    private(set) var client: Client!
     let instanceFeatures = InstanceFeatures()
     
-    @Published private(set) var account: AccountMO?
-    @Published private(set) var instance: InstanceV1?
-    @Published private var instanceV2: InstanceV2?
-    @Published private(set) var instanceInfo: InstanceInfo!
-    @Published private(set) var nodeInfo: NodeInfo!
-    @Published private(set) var lists: [List] = []
-    @Published private(set) var customEmojis: [Emoji]?
-    @Published private(set) var followedHashtags: [FollowedHashtag] = []
-    @Published private(set) var filters: [FilterMO] = []
+    @MainActor @Published private(set) var account: AccountMO?
+    @MainActor @Published private(set) var instance: InstanceV1?
+    @MainActor @Published private var instanceV2: InstanceV2?
+    @MainActor @Published private(set) var instanceInfo: InstanceInfo!
+    @MainActor @Published private(set) var nodeInfo: NodeInfo!
+    @MainActor @Published private(set) var lists: [List] = []
+    @MainActor @Published private(set) var customEmojis: [Emoji]?
+    @MainActor @Published private(set) var followedHashtags: [FollowedHashtag] = []
+    @MainActor @Published private(set) var filters: [FilterMO] = []
     
     private var cancellables = Set<AnyCancellable>()
     
-    private var pendingOwnInstanceRequestCallbacks = [(Result<InstanceV1, Client.Error>) -> Void]()
-    private var ownInstanceRequest: URLSessionTask?
+    @MainActor
+    private var fetchOwnInstanceTask: Task<InstanceV1, any Error>?
+    @MainActor
+    private var fetchOwnAccountTask: Task<MainThreadBox<AccountMO>, any Error>?
+    @MainActor
+    private var fetchCustomEmojisTask: Task<[Emoji], Never>?
     
     var loggedIn: Bool {
         accountInfo != nil
@@ -222,22 +229,37 @@ class MastodonController: ObservableObject {
         
         Task {
             do {
-                async let ownAccount = try getOwnAccount()
-                async let ownInstance = try getOwnInstance()
-                
-                _ = try await (ownAccount, ownInstance)
-                
-                if instanceFeatures.hasMastodonVersion(4, 0, 0) {
-                    async let _ = try? getOwnInstanceV2()
-                }
-                
-                loadLists()
-                _ = await loadFilters()
-                await loadServerPreferences()
+                _ = try await getOwnAccount()
             } catch {
-                Logging.general.error("MastodonController initialization failed: \(String(describing: error))")
+                logger.error("Fetch own account failed: \(String(describing: error))")
             }
         }
+        
+        let instanceTask = Task {
+            do {
+                _ = try await getOwnInstance()
+                if instanceFeatures.hasMastodonVersion(4, 0, 0) {
+                    _ = try? await getOwnInstanceV2()
+                }
+            } catch {
+                logger.error("Fetch instance failed: \(String(describing: error))")
+            }
+        }
+        
+        Task {
+            _ = await instanceTask.value
+            await loadLists()
+        }
+        
+        Task {
+            _ = await instanceTask.value
+            _ = await loadFilters()
+        }
+        
+        Task {
+            _ = await instanceTask.value
+            await loadServerPreferences()
+        }
     }
     
     @MainActor
@@ -250,131 +272,93 @@ class MastodonController: ObservableObject {
         }
     }
     
-    func getOwnAccount(completion: ((Result<AccountMO, Client.Error>) -> Void)? = nil) {
-        if let account {
-            completion?(.success(account))
-        } else {
-            let request = Client.getSelfAccount()
-            run(request) { response in
-                switch response {
-                case let .failure(error):
-                    completion?(.failure(error))
-                    
-                case let .success(account, _):
-                    let context = self.persistentContainer.viewContext
-                    context.perform {
-                        let accountMO: AccountMO
-                        if let existing = self.persistentContainer.account(for: account.id, in: context) {
-                            accountMO = existing
-                            existing.updateFrom(apiAccount: account, container: self.persistentContainer)
-                        } else {
-                            accountMO = self.persistentContainer.addOrUpdateSynchronously(account: account, in: context)
-                        }
-                        accountMO.active = true
-                        self.account = accountMO
-                        completion?(.success(accountMO))
-                    }
-                }
-            }
-        }
-    }
-    
+    @MainActor
     func getOwnAccount() async throws -> AccountMO {
-        if let account = account {
+        if let account {
             return account
+        } else if let fetchOwnAccountTask {
+            return try await fetchOwnAccountTask.value.value
         } else {
-            return try await withCheckedThrowingContinuation({ continuation in
-                self.getOwnAccount { result in
-                    continuation.resume(with: result)
+            let task = Task {
+                let account = try await run(Client.getSelfAccount()).0
+                
+                let context = persistentContainer.viewContext
+                // this closure is declared separately so we can tell the compiler it's Sendable
+                let performBlock: @MainActor @Sendable () -> MainThreadBox<AccountMO> = {
+                    let accountMO: AccountMO
+                    if let existing = self.persistentContainer.account(for: account.id, in: context) {
+                        accountMO = existing
+                        existing.updateFrom(apiAccount: account, container: self.persistentContainer)
+                    } else {
+                        accountMO = self.persistentContainer.addOrUpdateSynchronously(account: account, in: context)
+                    }
+                    // TODO: is AccountMO.active used anywhere?
+                    accountMO.active = true
+                    self.account = accountMO
+                    return MainThreadBox(value: accountMO)
                 }
-            })
+                // it's safe to remove the MainActor annotation, because this is the view context
+                return await context.perform(unsafeBitCast(performBlock, to: (@Sendable () -> MainThreadBox<AccountMO>).self))
+            }
+            fetchOwnAccountTask = task
+            return try await task.value.value
         }
     }
     
-    func getOwnInstance(completion: ((InstanceV1) -> Void)? = nil) {
-        getOwnInstanceInternal(retryAttempt: 0) {
-            if case let .success(instance) = $0 {
-                completion?(instance)
+    func getOwnInstance(completion: (@Sendable (InstanceV1) -> Void)? = nil) {
+        Task.detached {
+            let ownInstance = try? await self.getOwnInstance()
+            if let ownInstance {
+                completion?(ownInstance)
             }
         }
     }
     
     @MainActor
     func getOwnInstance() async throws -> InstanceV1 {
-        return try await withCheckedThrowingContinuation({ continuation in
-            getOwnInstanceInternal(retryAttempt: 0) { result in
-                continuation.resume(with: result)
-            }
-        })
-    }
-    
-    private func getOwnInstanceInternal(retryAttempt: Int, completion: ((Result<InstanceV1, Client.Error>) -> Void)?) {
-        // this is main thread only to prevent concurrent access to ownInstanceRequest and pendingOwnInstanceRequestCallbacks
-        assert(Thread.isMainThread)
-        
-        if let instance = self.instance {
-            completion?(.success(instance))
+        if let instance {
+            return instance
+        } else if let fetchOwnInstanceTask {
+            return try await fetchOwnInstanceTask.value
         } else {
-            if let completion = completion {
-                pendingOwnInstanceRequestCallbacks.append(completion)
-            }
-          
-            if ownInstanceRequest == nil {
-                let request = Client.getInstanceV1()
-                ownInstanceRequest = run(request) { (response) in
-                    switch response {
-                    case .failure(let error):
-                        let delay: DispatchTimeInterval
-                        switch retryAttempt {
-                        case 0:
-                            delay = .seconds(1)
-                        case 1:
-                            delay = .seconds(5)
-                        case 2:
-                            delay = .seconds(30)
-                        case 3:
-                            delay = .seconds(60)
-                        default:
-                            // if we've failed four times, just give up :/
-                            for completion in self.pendingOwnInstanceRequestCallbacks {
-                                completion(.failure(error))
-                            }
-                            self.pendingOwnInstanceRequestCallbacks = []
-                            return
-                        }
-                        DispatchQueue.main.asyncAfter(deadline: .now() + delay) {
-                            // completion is nil because in this invocation of getOwnInstanceInternal we've already added it to the pending callbacks array
-                            self.getOwnInstanceInternal(retryAttempt: retryAttempt + 1, completion: nil)
-                        }
-
-                    case let .success(instance, _):
-                        DispatchQueue.main.async {
-                            self.ownInstanceRequest = nil
-                            self.instance = instance
-                            
-                            for completion in self.pendingOwnInstanceRequestCallbacks {
-                                completion(.success(instance))
-                            }
-                            self.pendingOwnInstanceRequestCallbacks = []
-                        }
-                    }
+            let task = Task {
+                let instance = try await retrying("Fetch Own Instance") {
+                    try await run(Client.getInstanceV1()).0
+                }
+                self.instance = instance
+                
+                Task {
+                    await fetchNodeInfo()
                 }
                 
-                client.nodeInfo { result in
-                    switch result {
-                    case let .failure(error):
-                        print("Unable to get node info: \(error)")
-                        
-                    case let .success(nodeInfo, _):
-                        DispatchQueue.main.async {
-                            self.nodeInfo = nodeInfo
-                        }
-                    }
-                }
+                return instance
             }
+            fetchOwnInstanceTask = task
+            return try await task.value
         }
     }
     
+    @MainActor
+    private func fetchNodeInfo() async {
+        if let nodeInfo = try? await client.nodeInfo() {
+            self.nodeInfo = nodeInfo
+        }
+    }
+    
+    private func retrying<T: Sendable>(_ label: StaticString, action: @Sendable () async throws -> T) async throws -> T {
+        for attempt in 0..<4 {
+            do {
+                return try await action()
+            } catch {
+                let seconds = UInt64(truncating: pow(2, attempt) as NSNumber)
+                logger.error("\(label, privacy: .public) failed, waiting \(seconds, privacy: .public)s before retrying. Reason: \(String(describing: error))")
+                try! await Task.sleep(nanoseconds: seconds * NSEC_PER_SEC)
+            }
+        }
+        return try await action()
+    }
+    
+    @MainActor
     private func getOwnInstanceV2() async throws {
         self.instanceV2 = try await client.run(Client.getInstanceV2()).0
     }
@@ -425,43 +409,43 @@ class MastodonController: ObservableObject {
         }
     }
     
-    func getCustomEmojis(completion: @escaping ([Emoji]) -> Void) {
-        if let emojis = self.customEmojis {
-            completion(emojis)
+    @MainActor
+    func getCustomEmojis() async -> [Emoji] {
+        if let customEmojis {
+            return customEmojis
+        } else if let fetchCustomEmojisTask {
+            return await fetchCustomEmojisTask.value
         } else {
-            let request = Client.getCustomEmoji()
-            run(request) { (response) in
-                if case let .success(emojis, _) = response {
-                    DispatchQueue.main.async {
-                        self.customEmojis = emojis
-                    }
-                    completion(emojis)
-                } else {
-                    completion([])
-                }
+            let task = Task {
+                let emojis = (try? await run(Client.getCustomEmoji()).0) ?? []
+                customEmojis = emojis
+                return emojis
             }
+            fetchCustomEmojisTask = task
+            return await task.value
         }
     }
     
-    private func loadLists() {
+    private func loadLists() async {
         let req = Client.getLists()
-        run(req) { response in
-            if case .success(let lists, _) = response {
-                DispatchQueue.main.async {
-                    self.lists = lists.sorted(using: SemiCaseSensitiveComparator.keyPath(\.title))
-                }
-                let context = self.persistentContainer.backgroundContext
-                context.perform {
-                    for list in lists {
-                        if let existing = try? context.fetch(ListMO.fetchRequest(id: list.id)).first {
-                            existing.updateFrom(apiList: list)
-                        } else {
-                            _ = ListMO(apiList: list, context: context)
-                        }
-                    }
-                    self.persistentContainer.save(context: context)
+        guard let (lists, _) = try? await run(req) else {
+            return
+        }
+        let sorted = lists.sorted(using: SemiCaseSensitiveComparator.keyPath(\.title))
+        await MainActor.run {
+            self.lists = sorted
+        }
+        
+        let context = persistentContainer.backgroundContext
+        await context.perform {
+            for list in lists {
+                if let existing = try? context.fetch(ListMO.fetchRequest(id: list.id)).first {
+                    existing.updateFrom(apiList: list)
+                } else {
+                    _ = ListMO(apiList: list, context: context)
                 }
             }
+            self.persistentContainer.save(context: context)
         }
     }
     
@@ -548,6 +532,7 @@ class MastodonController: ObservableObject {
         filters = (try? persistentContainer.viewContext.fetch(FilterMO.fetchRequest())) ?? []
     }
     
+    @MainActor
     func createDraft(inReplyToID: String? = nil, mentioningAcct: String? = nil, text: String? = nil) -> Draft {
         var acctsToMention = [String]()
         
@@ -600,6 +585,7 @@ class MastodonController: ObservableObject {
         )
     }
     
+    @MainActor
     func createDraft(editing status: StatusMO, source: StatusSource) -> Draft {
         precondition(status.id == source.id)
         let draft = DraftsPersistentContainer.shared.createEditDraft(

Tusker/AppDelegate.swift

@@ -21,7 +21,7 @@ typealias Preferences = TuskerPreferences.Preferences
 let stateRestorationLogger = Logger(subsystem: Bundle.main.bundleIdentifier!, category: "StateRestoration")
 private let logger = Logger(subsystem: Bundle.main.bundleIdentifier!, category: "AppDelegate")
 
-@UIApplicationMain
+@main
 class AppDelegate: UIResponder, UIApplicationDelegate {
     
     func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?) -> Bool {

Tusker/Caching/ImageCache.swift

@@ -11,14 +11,19 @@ import UIKit
 #if os(visionOS)
 private let imageScale: CGFloat = 2
 #else
+@MainActor
 private let imageScale = UIScreen.main.scale
 #endif
 
-class ImageCache {
+final class ImageCache: @unchecked Sendable {
     
+    @MainActor
     static let avatars = ImageCache(name: "Avatars", memoryExpiry: .seconds(60 * 60), diskExpiry: .seconds(60 * 60 * 24 * 7), desiredSize: CGSize(width: 50, height: 50))
+    @MainActor
     static let headers = ImageCache(name: "Headers", memoryExpiry: .seconds(60 * 5), diskExpiry: .seconds(60 * 60 * 24 * 7))
+    @MainActor
     static let attachments = ImageCache(name: "Attachments", memoryExpiry: .seconds(60 * 2))
+    @MainActor
     static let emojis = ImageCache(name: "Emojis", memoryExpiry: .seconds(60 * 5), diskExpiry: .seconds(60 * 60 * 24 * 7))
     
     #if DEBUG
@@ -30,6 +35,7 @@ class ImageCache {
     private let cache: ImageDataCache
     private let desiredPixelSize: CGSize?
     
+    @MainActor
     init(name: String, memoryExpiry: CacheExpiry, diskExpiry: CacheExpiry? = nil, desiredSize: CGSize? = nil) {
         // todo: might not always want to use UIScreen.main for this, e.g. Catalyst?
         let pixelSize = desiredSize?.applying(.init(scaleX: imageScale, y: imageScale))
@@ -37,7 +43,7 @@ class ImageCache {
         self.cache = ImageDataCache(name: name, memoryExpiry: memoryExpiry, diskExpiry: diskExpiry, storeOriginalDataInMemory: diskExpiry == nil, desiredPixelSize: pixelSize)
     }
     
-    func get(_ url: URL, loadOriginal: Bool = false, completion: ((Data?, UIImage?) -> Void)?) -> Request? {
+    func get(_ url: URL, loadOriginal: Bool = false, completion: (@Sendable (Data?, UIImage?) -> Void)?) -> Request? {
         if !ImageCache.disableCaching,
            let entry = try? cache.get(url.absoluteString, loadOriginal: loadOriginal) {
             completion?(entry.data, entry.image)
@@ -47,7 +53,7 @@ class ImageCache {
         }
     }
     
-    func getFromSource(_ url: URL, completion: ((Data?, UIImage?) -> Void)?) -> Request? {
+    func getFromSource(_ url: URL, completion: (@Sendable (Data?, UIImage?) -> Void)?) -> Request? {
         return Task.detached(priority: .userInitiated) {
             let result = await self.fetch(url: url)
             switch result {

Tusker/CoreData/MastodonCachePersistentStore.swift

@@ -550,14 +550,19 @@ class MastodonCachePersistentStore: NSPersistentCloudKitContainer {
                         }
                     }
                 }
+                // Can't capture vars in concurrently-executing closure
+                let hashtags = changedHashtags
+                let instances = changedInstances
+                let timelinePositions = changedTimelinePositions
+                let accountPrefs = changedAccountPrefs
                 DispatchQueue.main.async {
-                    if changedHashtags {
+                    if hashtags {
                         NotificationCenter.default.post(name: .savedHashtagsChanged, object: nil)
                     }
-                    if changedInstances {
+                    if instances {
                         NotificationCenter.default.post(name: .savedInstancesChanged, object: nil)
                     }
-                    for id in changedTimelinePositions {
+                    for id in timelinePositions {
                         guard let timelinePosition = try? self.viewContext.existingObject(with: id) as? TimelinePosition else {
                             continue
                         }
@@ -565,7 +570,7 @@ class MastodonCachePersistentStore: NSPersistentCloudKitContainer {
                         timelinePosition.changedRemotely()
                         NotificationCenter.default.post(name: .timelinePositionChanged, object: timelinePosition)
                     }
-                    if changedAccountPrefs {
+                    if accountPrefs {
                         NotificationCenter.default.post(name: .accountPreferencesChangedRemotely, object: nil)
                     }
                 }

Tusker/Extensions/MainActor+Unsafe.swift

@@ -9,7 +9,7 @@
 import Foundation
 
 /*
- Copied from https://github.com/ChimeHQ/ConcurrencyPlus/blob/fe3b3fd5436b196d8c5211ab2cc4b69fc35524fe/Sources/ConcurrencyPlus/MainActor%2BUnsafe.swift
+ Copied from https://github.com/ChimeHQ/ConcurrencyPlus/blob/daf69ed837fa04d4ba666f5a99378cf1815f0dab/Sources/ConcurrencyPlus/MainActor%2BUnsafe.swift
  
  Copyright (c) 2022, Chime
  All rights reserved.
@@ -46,10 +46,23 @@ public extension MainActor {
     /// This function exists to work around libraries with incorrect/inconsistent concurrency annotations. You should be **extremely** careful when using it, and only as a last resort.
     ///
     /// It will crash if run on any non-main thread.
-    @MainActor(unsafe)
+    @_unavailableFromAsync
     static func runUnsafely<T>(_ body: @MainActor () throws -> T) rethrows -> T {
+        if #available(macOS 14.0, iOS 17.0, watchOS 10.0, tvOS 17.0, *) {
+            return try MainActor.assumeIsolated(body)
+        }
+        
         dispatchPrecondition(condition: .onQueue(.main))
-
-        return try body()
+        return try withoutActuallyEscaping(body) { fn in
+            try unsafeBitCast(fn, to: (() throws -> T).self)()
+        }
+    }
+    
+    @_unavailableFromAsync
+    @available(*, deprecated, message: "Tool of last resort, do not use this.")
+    static func runUnsafelyMaybeIntroducingDataRace<T>(_ body: @MainActor () throws -> T) rethrows -> T {
+        return try withoutActuallyEscaping(body) { fn in
+            try unsafeBitCast(fn, to: (() throws -> T).self)()
+        }
     }
 }

Tusker/Extensions/View+AppListStyle.swift

@@ -10,6 +10,7 @@ import SwiftUI
 import Combine
 
 extension View {
+    @MainActor
     @ViewBuilder
     func appGroupedListBackground(container: UIAppearanceContainer.Type, applyBackground: Bool = true) -> some View {
         if #available(iOS 16.0, *) {

Tusker/ImageGrayscalifier.swift

@@ -15,7 +15,10 @@ struct ImageGrayscalifier {
     private static let cache = NSCache<NSURL, UIImage>()
 
     static func convertIfNecessary(url: URL?, image: UIImage) -> UIImage? {
-        if Preferences.shared.grayscaleImages,
+        let grayscale = MainActor.runUnsafelyMaybeIntroducingDataRace {
+            Preferences.shared.grayscaleImages
+        }
+        if grayscale,
            let source = image.cgImage {
             // todo: should this return the original image if conversion fails?
             return convert(url: url, cgImage: source)
@@ -24,6 +27,18 @@ struct ImageGrayscalifier {
         }
     }
     
+    static func convertIfNecessary(url: URL?, image: UIImage) async -> UIImage? {
+        let grayscale = await MainActor.run {
+            Preferences.shared.grayscaleImages
+        }
+        if grayscale,
+           let source = image.cgImage {
+            return await convert(url: url, cgImage: source)
+        } else {
+            return image
+        }
+    }
+    
     static func convert(url: URL?, image: UIImage) -> UIImage? {
         if let url,
            let cached = cache.object(forKey: url as NSURL) {
@@ -35,6 +50,21 @@ struct ImageGrayscalifier {
         return doConvert(CIImage(cgImage: cgImage), url: url)
     }
     
+    static func convert(url: URL?, image: UIImage) async -> UIImage? {
+        if let url,
+           let cached = cache.object(forKey: url as NSURL) {
+            return cached
+        }
+        guard let cgImage = image.cgImage else {
+            return nil
+        }
+        return await withCheckedContinuation { continuation in
+            queue.async {
+                continuation.resume(returning: doConvert(CIImage(cgImage: cgImage), url: url))
+            }
+        }
+    }
+    
     static func convert(url: URL?, data: Data) -> UIImage? {
         if let url = url,
            let cached = cache.object(forKey: url as NSURL) {
@@ -56,6 +86,18 @@ struct ImageGrayscalifier {
         return doConvert(CIImage(cgImage: cgImage), url: url)
     }
     
+    static func convert(url: URL?, cgImage: CGImage) async -> UIImage? {
+        if let url = url,
+           let cached = cache.object(forKey: url as NSURL) {
+            return cached
+        }
+        return await withCheckedContinuation { continuation in
+            queue.async {
+                continuation.resume(returning: doConvert(CIImage(cgImage: cgImage), url: url))
+            }
+        }
+    }
+    
     private static func doConvert(_ source: CIImage, url: URL?) -> UIImage? {
         guard let filter = CIFilter(name: "CIColorMonochrome") else {
             return nil

Tusker/MainThreadBox.swift

@@ -0,0 +1,23 @@
+//
+//  MainThreadBox.swift
+//  Tusker
+//
+//  Created by Shadowfacts on 1/27/24.
+//  Copyright © 2024 Shadowfacts. All rights reserved.
+//
+
+import Foundation
+
+struct MainThreadBox<T>: @unchecked Sendable {
+    private let _value: T
+    
+    @MainActor
+    var value: T {
+        _value
+    }
+    
+    @MainActor
+    init(value: T) {
+        self._value = value
+    }
+}

Tusker/MenuController.swift

@@ -8,6 +8,7 @@
 
 import UIKit
 
+@MainActor
 struct MenuController {
     
     static let composeCommand: UIKeyCommand = {

Tusker/MultiThreadDictionary.swift

@@ -13,7 +13,7 @@ import os
 // to make the lock semantics more clear
 @available(iOS, obsoleted: 16.0)
 @available(visionOS 1.0, *)
-class MultiThreadDictionary<Key: Hashable & Sendable, Value: Sendable> {
+final class MultiThreadDictionary<Key: Hashable & Sendable, Value: Sendable>: @unchecked Sendable {
     #if os(visionOS)
     private let lock = OSAllocatedUnfairLock(initialState: [Key: Value]())
     #else

Tusker/Preferences/StatusSwipeActions.swift

@@ -11,6 +11,7 @@ import Pachyderm
 import TuskerPreferences
 
 extension StatusSwipeAction {
+    @MainActor
     func createAction(status: StatusMO, container: StatusSwipeActionContainer) -> UIContextualAction? {
         switch self {
         case .reply:
@@ -29,6 +30,7 @@ extension StatusSwipeAction {
     }
 }
 
+@MainActor
 protocol StatusSwipeActionContainer: UIView {
     var mastodonController: MastodonController! { get }
     var navigationDelegate: any TuskerNavigationDelegate { get }
@@ -40,6 +42,7 @@ protocol StatusSwipeActionContainer: UIView {
     func performReplyAction()
 }
 
+@MainActor
 private func createReplyAction(status: StatusMO, container: StatusSwipeActionContainer) -> UIContextualAction? {
     guard container.mastodonController.loggedIn else {
         return nil
@@ -53,6 +56,7 @@ private func createReplyAction(status: StatusMO, container: StatusSwipeActionCon
     return action
 }
 
+@MainActor
 private func createFavoriteAction(status: StatusMO, container: StatusSwipeActionContainer) -> UIContextualAction? {
     guard container.mastodonController.loggedIn else {
         return nil
@@ -69,6 +73,7 @@ private func createFavoriteAction(status: StatusMO, container: StatusSwipeAction
     return action
 }
 
+@MainActor
 private func createReblogAction(status: StatusMO, container: StatusSwipeActionContainer) -> UIContextualAction? {
     guard container.mastodonController.loggedIn,
           container.canReblog else {
@@ -86,6 +91,7 @@ private func createReblogAction(status: StatusMO, container: StatusSwipeActionCo
     return action
 }
 
+@MainActor
 private func createShareAction(status: StatusMO, container: StatusSwipeActionContainer) -> UIContextualAction {
     let action = UIContextualAction(style: .normal, title: "Share") { [unowned container] _, _, completion in
         MainActor.runUnsafely {
@@ -100,6 +106,7 @@ private func createShareAction(status: StatusMO, container: StatusSwipeActionCon
     return action
 }
 
+@MainActor
 private func createBookmarkAction(status: StatusMO, container: StatusSwipeActionContainer) -> UIContextualAction? {
     guard container.mastodonController.loggedIn else {
         return nil
@@ -124,11 +131,10 @@ private func createBookmarkAction(status: StatusMO, container: StatusSwipeAction
     return action
 }
 
+@MainActor
 private func createOpenInSafariAction(status: StatusMO, container: StatusSwipeActionContainer) -> UIContextualAction {
     let action = UIContextualAction(style: .normal, title: "Open in Safari") { [unowned container] _, _, completion in
-        MainActor.runUnsafely {
-            container.navigationDelegate.selected(url: status.url!, allowUniversalLinks: false)
-        }
+        container.navigationDelegate.selected(url: status.url!, allowUniversalLinks: false)
         completion(true)
     }
     action.image = UIImage(systemName: "safari")

Tusker/SavedDataManager.swift

@@ -10,10 +10,14 @@ import Foundation
 import Pachyderm
 import CoreData
 
+// TODO: remove this class eventually
 class SavedDataManager: Codable {
+    @MainActor
     private static var documentsDirectory = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask).first!
+    @MainActor
     private static var archiveURL = SavedDataManager.documentsDirectory.appendingPathComponent("saved_data").appendingPathExtension("plist")
     
+    @MainActor
     static func load() -> SavedDataManager? {
         let decoder = PropertyListDecoder()
         if let data = try? Data(contentsOf: archiveURL),
@@ -23,6 +27,7 @@ class SavedDataManager: Codable {
         return nil
     }
     
+    @MainActor
     static func destroy() throws {
         try FileManager.default.removeItem(at: archiveURL)
     }
@@ -39,6 +44,7 @@ class SavedDataManager: Codable {
         return s
     }
     
+    @MainActor
     private func save() {
         let encoder = PropertyListEncoder()
         let data = try? encoder.encode(self)
@@ -46,8 +52,6 @@ class SavedDataManager: Codable {
     }
     
     func migrateToCoreData(accountID: String, context: NSManagedObjectContext) throws {
-        var changed = false
-        
         if let hashtags = savedHashtags[accountID] {
             let objects: [[String: Any]] = hashtags.map {
                 ["url": $0.url, "name": $0.name]
@@ -55,7 +59,6 @@ class SavedDataManager: Codable {
             let hashtagsReq = NSBatchInsertRequest(entity: SavedHashtag.entity(), objects: objects)
             try context.execute(hashtagsReq)
             savedHashtags.removeValue(forKey: accountID)
-            changed = true
         }
         
         if let instances = savedInstances[accountID] {
@@ -65,11 +68,6 @@ class SavedDataManager: Codable {
             let instancesReq = NSBatchInsertRequest(entity: SavedInstance.entity(), objects: objects)
             try context.execute(instancesReq)
             savedInstances.removeValue(forKey: accountID)
-            changed = true
-        }
-        
-        if changed {
-            save()
         }
     }
 }

Tusker/Scenes/TuskerSceneDelegate.swift

@@ -11,6 +11,7 @@ import UIKit
 import Sentry
 #endif
 
+@MainActor
 protocol TuskerSceneDelegate: UISceneDelegate {
     var window: UIWindow? { get }
     var rootViewController: TuskerRootViewController? { get }

Tusker/Screens/Compose/ComposeDrawingViewController.swift

@@ -9,6 +9,7 @@
 import UIKit
 import PencilKit
 
+@MainActor
 protocol ComposeDrawingViewControllerDelegate: AnyObject {
     func composeDrawingViewControllerClose(_ drawingController: ComposeDrawingViewController)
     func composeDrawingViewController(_ drawingController: ComposeDrawingViewController, saveDrawing drawing: PKDrawing)

Tusker/Screens/Compose/ComposeHostingController.swift

@@ -18,6 +18,7 @@ import CoreData
 import Duckable
 #endif
 
+@MainActor
 protocol ComposeHostingControllerDelegate: AnyObject {
     func dismissCompose(mode: DismissMode) -> Bool
 }

Tusker/Screens/Conversation/ConversationCollectionViewController.swift

@@ -296,7 +296,7 @@ extension ConversationCollectionViewController {
         case mainStatus
         case childThread(firstStatusID: String)
     }
-    enum Item: Hashable {
+    enum Item: Hashable, Sendable {
         case status(id: String, node: ConversationNode, state: CollapseState, prevLink: Bool, nextLink: Bool)
         case expandThread(childThreads: [ConversationNode], inline: Bool)
         case loadingIndicator
@@ -306,7 +306,7 @@ extension ConversationCollectionViewController {
             case let (.status(id: a, node: _, state: _, prevLink: aPrev, nextLink: aNext), .status(id: b, node: _, state: _, prevLink: bPrev, nextLink: bNext)):
                 return a == b && aPrev == bPrev && aNext == bNext
             case let (.expandThread(childThreads: a, inline: aInline), .expandThread(childThreads: b, inline: bInline)):
-                return a.count == b.count && zip(a, b).allSatisfy { $0.status.id == $1.status.id } && aInline == bInline
+                return a.count == b.count && zip(a, b).allSatisfy { $0.statusID == $1.statusID } && aInline == bInline
             case (.loadingIndicator, .loadingIndicator):
                 return true
             default:
@@ -324,7 +324,7 @@ extension ConversationCollectionViewController {
             case .expandThread(childThreads: let childThreads, inline: let inline):
                 hasher.combine(1)
                 for thread in childThreads {
-                    hasher.combine(thread.status.id)
+                    hasher.combine(thread.statusID)
                 }
                 hasher.combine(inline)
             case .loadingIndicator:

Tusker/Screens/Conversation/ConversationTree.swift

@@ -9,15 +9,20 @@
 import Foundation
 import Pachyderm
 
+@MainActor
 class ConversationNode {
+    let statusID: String
     let status: StatusMO
     var children: [ConversationNode]
     
     init(status: StatusMO) {
+        self.statusID = status.id
         self.status = status
         self.children = []
     }
 }
+
+@MainActor
 struct ConversationTree {
     let ancestors: [ConversationNode]
     let mainStatus: ConversationNode

Tusker/Screens/Conversation/ConversationViewController.swift

@@ -194,7 +194,7 @@ class ConversationViewController: UIViewController {
         if let cached = mastodonController.persistentContainer.status(for: mainStatusID) {
             // if we have a cached copy, display it immediately but still try to refresh it
             Task {
-                await doLoadMainStatus()
+                _ = await doLoadMainStatus()
             }
             mainStatusLoaded(cached)
         } else {
@@ -216,7 +216,7 @@ class ConversationViewController: UIViewController {
         state = .loading(indicator)
         
         let effectiveURL: String
-        class RedirectBlocker: NSObject, URLSessionTaskDelegate {
+        final class RedirectBlocker: NSObject, URLSessionTaskDelegate, Sendable {
             func urlSession(_ session: URLSession, task: URLSessionTask, willPerformHTTPRedirection response: HTTPURLResponse, newRequest request: URLRequest, completionHandler: @escaping (URLRequest?) -> Void) {
                 completionHandler(nil)
             }

Tusker/Screens/Crash Reporter/IssueReporterViewController.swift

@@ -166,13 +166,15 @@ class IssueReporterViewController: UIViewController {
 }
 
 extension IssueReporterViewController: MFMailComposeViewControllerDelegate {
-    func mailComposeController(_ controller: MFMailComposeViewController, didFinishWith result: MFMailComposeResult, error: Error?) {
-        controller.dismiss(animated: true) {
-            if result == .cancelled {
-                // don't dismiss ourself, to allowe the user to send the report a different way
-            } else {
-                self.finishedReport()
-                self.doDismiss()
+    nonisolated func mailComposeController(_ controller: MFMailComposeViewController, didFinishWith result: MFMailComposeResult, error: Error?) {
+        MainActor.runUnsafely {
+            controller.dismiss(animated: true) {
+                if result == .cancelled {
+                    // don't dismiss ourself, to allowe the user to send the report a different way
+                } else {
+                    self.finishedReport()
+                    self.doDismiss()
+                }
             }
         }
     }

Tusker/Screens/Explore/ExploreViewController.swift

@@ -14,7 +14,7 @@ import WebURLFoundationExtras
 
 class ExploreViewController: UIViewController, UICollectionViewDelegate, CollectionViewController {
 
-    weak var mastodonController: MastodonController!
+    private let mastodonController: MastodonController
     
     var collectionView: UICollectionView!
     private var dataSource: UICollectionViewDiffableDataSource<Section, Item>!

Tusker/Screens/Explore/FeaturedProfileCollectionViewCell.swift

@@ -20,8 +20,11 @@ class FeaturedProfileCollectionViewCell: UICollectionViewCell {
     
     var account: Account?
     
-    private var avatarRequest: ImageCache.Request?
-    private var headerRequest: ImageCache.Request?
+    private var accountImagesTask: Task<Void, Never>?
+    
+    deinit {
+        accountImagesTask?.cancel()
+    }
     
     override func awakeFromNib() {
         super.awakeFromNib()
@@ -62,37 +65,35 @@ class FeaturedProfileCollectionViewCell: UICollectionViewCell {
         noteTextView.setEmojis(account.emojis, identifier: account.id)
         
         avatarImageView.image = nil
-        if let avatar = account.avatar {
-            avatarRequest = ImageCache.avatars.get(avatar) { [weak self] (_, image) in
-                defer {
-                    self?.avatarRequest = nil
-                }
-                guard let self = self,
-                      let image = image,
-                      self.account?.id == account.id else {
+        headerImageView.image = nil
+        
+        accountImagesTask?.cancel()
+        accountImagesTask = Task {
+            await updateImages(account: account)
+        }
+    }
+    
+    private nonisolated func updateImages(account: Account) async {
+        await withTaskGroup(of: Void.self) { group in
+            group.addTask {
+                guard let avatar = account.avatar,
+                      let image = await ImageCache.avatars.get(avatar).1 else {
                     return
                 }
-                DispatchQueue.main.async {
+                await MainActor.run {
                     self.avatarImageView.image = image
                 }
             }
-        }
-        
-        headerImageView.image = nil
-        if let header = account.header {
-            headerRequest = ImageCache.headers.get(header) { [weak self] (_, image) in
-                defer {
-                    self?.headerRequest = nil
-                }
-                guard let self = self,
-                      let image = image,
-                      self.account?.id == account.id else {
+            group.addTask {
+                guard let header = account.header,
+                      let image = await ImageCache.headers.get(header).1 else {
                     return
                 }
-                DispatchQueue.main.async {
+                await MainActor.run {
                     self.headerImageView.image = image
                 }
             }
+            await group.waitForAll()
         }
     }
     

Tusker/Screens/Explore/ProfileDirectoryViewController.swift

@@ -11,7 +11,7 @@ import Pachyderm
 
 class ProfileDirectoryViewController: UIViewController {
 
-    weak var mastodonController: MastodonController!
+    private let mastodonController: MastodonController
     
     private var collectionView: UICollectionView!
     private var dataSource: UICollectionViewDiffableDataSource<Section, Item>!

Tusker/Screens/Explore/SuggestedProfilesViewController.swift

@@ -11,7 +11,7 @@ import Pachyderm
 
 class SuggestedProfilesViewController: UIViewController, CollectionViewController {
     
-    weak var mastodonController: MastodonController!
+    private let mastodonController: MastodonController
     
     var collectionView: UICollectionView!
     private var layout: MultiColumnCollectionViewLayout!
@@ -95,7 +95,9 @@ class SuggestedProfilesViewController: UIViewController, CollectionViewControlle
         
         var snapshot = NSDiffableDataSourceSnapshot<Section, Item>()
         snapshot.appendSections([.accounts])
-        await dataSource.apply(snapshot)
+        await MainActor.run {
+            dataSource.apply(snapshot)
+        }
         
         do {
             let request = Client.getSuggestions(limit: 80)
@@ -108,7 +110,9 @@ class SuggestedProfilesViewController: UIViewController, CollectionViewControlle
             var snapshot = NSDiffableDataSourceSnapshot<Section, Item>()
             snapshot.appendSections([.accounts])
             snapshot.appendItems(suggestions.map { .account($0.account.id, $0.source) })
-            await dataSource.apply(snapshot)
+            await MainActor.run {
+                dataSource.apply(snapshot)
+            }
             
             state = .loaded
         } catch {

Tusker/Screens/Explore/TrendingHashtagsViewController.swift

@@ -13,7 +13,7 @@ import Combine
 
 class TrendingHashtagsViewController: UIViewController {
 
-    weak var mastodonController: MastodonController!
+    private let mastodonController: MastodonController
     
     private var collectionView: UICollectionView!
     private var dataSource: UICollectionViewDiffableDataSource<Section, Item>!
@@ -107,7 +107,9 @@ class TrendingHashtagsViewController: UIViewController {
         var snapshot = NSDiffableDataSourceSnapshot<Section, Item>()
         snapshot.appendSections([.trendingTags])
         snapshot.appendItems([.loadingIndicator])
-        await dataSource.apply(snapshot)
+        await MainActor.run {
+            dataSource.apply(snapshot)
+        }
         
         do {
             let request = self.request(offset: nil)
@@ -115,10 +117,14 @@ class TrendingHashtagsViewController: UIViewController {
             snapshot.deleteItems([.loadingIndicator])
             snapshot.appendItems(hashtags.map { .tag($0) })
             state = .loaded
-            await dataSource.apply(snapshot)
+            await MainActor.run {
+                dataSource.apply(snapshot)
+            }
         } catch {
             snapshot.deleteItems([.loadingIndicator])
-            await dataSource.apply(snapshot)
+            await MainActor.run {
+                dataSource.apply(snapshot)
+            }
             state = .unloaded
             
             let config = ToastConfiguration(from: error, with: "Error Loading Trending Tags", in: self) { [weak self] toast in
@@ -140,7 +146,9 @@ class TrendingHashtagsViewController: UIViewController {
         var snapshot = origSnapshot
         if Preferences.shared.disableInfiniteScrolling {
             snapshot.appendItems([.confirmLoadMore(false)])
-            await dataSource.apply(snapshot)
+            await MainActor.run {
+                dataSource.apply(snapshot)
+            }
             
             for await _ in confirmLoadMore.values {
                 break
@@ -148,10 +156,14 @@ class TrendingHashtagsViewController: UIViewController {
             
             snapshot.deleteItems([.confirmLoadMore(false)])
             snapshot.appendItems([.confirmLoadMore(true)])
-            await dataSource.apply(snapshot, animatingDifferences: false)
+            await MainActor.run {
+                dataSource.apply(snapshot, animatingDifferences: false)
+            }
         } else {
             snapshot.appendItems([.loadingIndicator])
-            await dataSource.apply(snapshot)
+            await MainActor.run {
+                dataSource.apply(snapshot)
+            }
         }
         
         do {
@@ -159,9 +171,13 @@ class TrendingHashtagsViewController: UIViewController {
             let (hashtags, _) = try await mastodonController.run(request)
             var snapshot = origSnapshot
             snapshot.appendItems(hashtags.map { .tag($0) })
-            await dataSource.apply(snapshot)
+            await MainActor.run {
+                dataSource.apply(snapshot)
+            }
         } catch {
-            await dataSource.apply(origSnapshot)
+            await MainActor.run {
+                dataSource.apply(origSnapshot)
+            }
             
             let config = ToastConfiguration(from: error, with: "Error Loading More Tags", in: self) { [weak self] toast in
                 toast.dismissToast(animated: true)

Tusker/Screens/Explore/TrendingLinksViewController.swift

@@ -14,7 +14,7 @@ import Combine
 
 class TrendingLinksViewController: UIViewController, CollectionViewController {
     
-    weak var mastodonController: MastodonController!
+    private let mastodonController: MastodonController
     
     var collectionView: UICollectionView!
     private var dataSource: UICollectionViewDiffableDataSource<Section, Item>!
@@ -128,7 +128,9 @@ class TrendingLinksViewController: UIViewController, CollectionViewController {
         var snapshot = NSDiffableDataSourceSnapshot<Section, Item>()
         snapshot.appendSections([.loadingIndicator])
         snapshot.appendItems([.loadingIndicator])
-        await dataSource.apply(snapshot)
+        await MainActor.run {
+            dataSource.apply(snapshot)
+        }
         
         do {
             let request = Client.getTrendingLinks()
@@ -137,9 +139,13 @@ class TrendingLinksViewController: UIViewController, CollectionViewController {
             snapshot.appendSections([.links])
             snapshot.appendItems(links.map { .link($0) })
             state = .loaded
-            await dataSource.apply(snapshot)
+            await MainActor.run {
+                dataSource.apply(snapshot)
+            }
         } catch {
-            await dataSource.apply(NSDiffableDataSourceSnapshot())
+            await MainActor.run {
+                dataSource.apply(NSDiffableDataSourceSnapshot())
+            }
             state = .unloaded
             let config = ToastConfiguration(from: error, with: "Error Loading Trending Links", in: self) { [weak self] toast in
                 toast.dismissToast(animated: true)
@@ -161,7 +167,9 @@ class TrendingLinksViewController: UIViewController, CollectionViewController {
         if Preferences.shared.disableInfiniteScrolling {
             snapshot.appendSections([.loadingIndicator])
             snapshot.appendItems([.confirmLoadMore(false)], toSection: .loadingIndicator)
-            await dataSource.apply(snapshot)
+            await MainActor.run {
+                dataSource.apply(snapshot)
+            }
             
             for await _ in confirmLoadMore.values {
                 break
@@ -169,11 +177,15 @@ class TrendingLinksViewController: UIViewController, CollectionViewController {
             
             snapshot.deleteItems([.confirmLoadMore(false)])
             snapshot.appendItems([.confirmLoadMore(true)], toSection: .loadingIndicator)
-            await dataSource.apply(snapshot, animatingDifferences: false)
+            await MainActor.run {
+                dataSource.apply(snapshot, animatingDifferences: false)
+            }
         } else {
             snapshot.appendSections([.loadingIndicator])
             snapshot.appendItems([.loadingIndicator], toSection: .loadingIndicator)
-            await dataSource.apply(snapshot)
+            await MainActor.run {
+                dataSource.apply(snapshot)
+            }
         }
         
         do {
@@ -181,9 +193,13 @@ class TrendingLinksViewController: UIViewController, CollectionViewController {
             let (links, _) = try await mastodonController.run(request)
             var snapshot = origSnapshot
             snapshot.appendItems(links.map { .link($0) }, toSection: .links)
-            await dataSource.apply(snapshot)
+            await MainActor.run {
+                dataSource.apply(snapshot)
+            }
         } catch {
-            await dataSource.apply(origSnapshot)
+            await MainActor.run {
+                dataSource.apply(origSnapshot)
+            }
             let config = ToastConfiguration(from: error, with: "Erorr Loading More Links", in: self) { [weak self] toast in
                 toast.dismissToast(animated: true)
                 await self?.loadOlder()

Tusker/Screens/Explore/TrendingStatusesViewController.swift

@@ -11,7 +11,7 @@ import Pachyderm
 
 class TrendingStatusesViewController: UIViewController, CollectionViewController {
     
-    weak var mastodonController: MastodonController!
+    private let mastodonController: MastodonController
     let filterer: Filterer
     
     var collectionView: UICollectionView! {
@@ -126,7 +126,9 @@ class TrendingStatusesViewController: UIViewController, CollectionViewController
             statuses = try await mastodonController.run(Client.getTrendingStatuses()).0
         } catch {
             let snapshot = NSDiffableDataSourceSnapshot<Section, Item>()
-            await dataSource.apply(snapshot)
+            await MainActor.run {
+                dataSource.apply(snapshot)
+            }
             let config = ToastConfiguration(from: error, with: "Loading Trending Posts", in: self) { toast in
                 toast.dismissToast(animated: true)
                 await self.loadTrendingStatuses()
@@ -138,7 +140,9 @@ class TrendingStatusesViewController: UIViewController, CollectionViewController
         var snapshot = NSDiffableDataSourceSnapshot<Section, Item>()
         snapshot.appendSections([.statuses])
         snapshot.appendItems(statuses.map { .status(id: $0.id, collapseState: .unknown, filterState: .unknown) })
-        await dataSource.apply(snapshot)
+        await MainActor.run {
+            dataSource.apply(snapshot)
+        }
     }
     
     @objc private func handleStatusDeleted(_ notification: Foundation.Notification) {

Tusker/Screens/Explore/TrendsViewController.swift

@@ -238,7 +238,7 @@ class TrendsViewController: UIViewController, CollectionViewController {
         }
         isShowingTrends = shouldShowTrends
         guard shouldShowTrends else {
-            await dataSource.apply(NSDiffableDataSourceSnapshot())
+            await apply(snapshot: NSDiffableDataSourceSnapshot())
             return
         }
         
@@ -355,9 +355,9 @@ class TrendsViewController: UIViewController, CollectionViewController {
     }
     
     private func apply(snapshot: NSDiffableDataSourceSnapshot<Section, Item>, animatingDifferences: Bool = true) async {
-        await Task { @MainActor in
+        await MainActor.run {
             self.dataSource.apply(snapshot, animatingDifferences: animatingDifferences)
-        }.value
+        }
     }
     
     @MainActor

Tusker/Screens/Fast Account Switcher/FastAccountSwitcherViewController.swift

@@ -9,6 +9,7 @@
 import UIKit
 import UserAccounts
 
+@MainActor
 protocol FastAccountSwitcherViewControllerDelegate: AnyObject {
     func fastAccountSwitcherAddToViewHierarchy(_ fastAccountSwitcher: FastAccountSwitcherViewController)
     /// - Parameter point: In the coordinate space of the view to which the pan gesture recognizer is attached.

Tusker/Screens/Fast Account Switcher/FastSwitchingAccountView.swift

@@ -49,7 +49,7 @@ class FastSwitchingAccountView: UIView {
     private let instanceLabel = UILabel()
     private let avatarImageView = UIImageView()
     
-    private var avatarRequest: ImageCache.Request?
+    private var avatarTask: Task<Void, Never>?
     
     init(account: UserAccountInfo, orientation: FastAccountSwitcherViewController.ItemOrientation) {
         self.orientation = orientation
@@ -69,6 +69,10 @@ class FastSwitchingAccountView: UIView {
         fatalError("init(coder:) has not been implemented")
     }
     
+    deinit {
+        avatarTask?.cancel()
+    }
+    
     private func commonInit() {
         usernameLabel.textColor = .white
         usernameLabel.font = UIFont(descriptor: .preferredFontDescriptor(withTextStyle: .headline), size: 0)
@@ -133,16 +137,13 @@ class FastSwitchingAccountView: UIView {
             instanceLabel.text = account.instanceURL.host!
         }
         let controller = MastodonController.getForAccount(account)
-        controller.getOwnAccount { [weak self] (result) in
-            guard let self = self,
-                  case let .success(account) = result,
-                  let avatar = account.avatar else { return }
-            self.avatarRequest = ImageCache.avatars.get(avatar) { [weak self] (_, image) in
-                guard let self = self, let image = image else { return }
-                DispatchQueue.main.async {
-                    self.avatarImageView.image = image
-                }
+        avatarTask = Task {
+            guard let account = try? await controller.getOwnAccount(),
+                  let avatar = account.avatar,
+                  let image = await ImageCache.avatars.get(avatar).1 else {
+                return
             }
+            self.avatarImageView.image = image
         }
         
         accessibilityLabel = "\(account.username!)@\(instanceLabel.text!)"

Tusker/Screens/Large Image/GalleryFallbackViewController.swift

@@ -57,12 +57,14 @@ class GalleryFallbackViewController: QLPreviewController {
 }
 
 extension GalleryFallbackViewController: QLPreviewControllerDataSource {
-    func numberOfPreviewItems(in controller: QLPreviewController) -> Int {
+    nonisolated func numberOfPreviewItems(in controller: QLPreviewController) -> Int {
         return 1
     }
     
-    func previewController(_ controller: QLPreviewController, previewItemAt index: Int) -> QLPreviewItem {
-        return previewItem
+    nonisolated func previewController(_ controller: QLPreviewController, previewItemAt index: Int) -> QLPreviewItem {
+        return MainActor.runUnsafely {
+            previewItem
+        }
     }
 }
 

Tusker/Screens/Large Image/LargeImageContentView.swift

@@ -12,6 +12,7 @@ import Pachyderm
 @preconcurrency import VisionKit
 import TuskerComponents
 
+@MainActor
 protocol LargeImageContentView: UIView {
     var animationImage: UIImage? { get }
     var activityItemsForSharing: [Any] { get }

Tusker/Screens/Large Image/LargeImageViewController.swift

@@ -144,7 +144,9 @@ class LargeImageViewController: UIViewController, UIScrollViewDelegate, LargeIma
             contentViewTopConstraint,
         ])
         contentViewSizeObservation = (contentView as UIView).observe(\.bounds, changeHandler: { [unowned self] _, _ in
-            self.centerImage()
+            MainActor.runUnsafely {
+                self.centerImage()
+            }
         })
     }
     

Tusker/Screens/Large Image/LoadingLargeImageViewController.swift

@@ -105,8 +105,8 @@ class LoadingLargeImageViewController: UIViewController, LargeImageAnimatableVie
             embedChild(loadingVC!)
             imageRequest = cache.get(url, loadOriginal: true) { [weak self] (data, image) in
                 guard let self = self, let image = image else { return }
-                self.imageRequest = nil
                 DispatchQueue.main.async {
+                    self.imageRequest = nil
                     self.loadingVC?.removeViewAndController()
                     self.createLargeImage(data: data, image: image, url: self.url)
                 }

Tusker/Screens/Large Image/Transitions/LargeImageExpandAnimationController.swift

@@ -9,6 +9,7 @@
 import UIKit
 import TuskerComponents
 
+@MainActor
 protocol LargeImageAnimatableViewController: UIViewController {
     var animationSourceView: UIImageView? { get }
     var largeImageController: LargeImageViewController? { get }

Tusker/Screens/Lists/EditListAccountsViewController.swift

@@ -195,7 +195,9 @@ class EditListAccountsViewController: UIViewController, CollectionViewController
         var snapshot = NSDiffableDataSourceSnapshot<Section, Item>()
         snapshot.appendSections([.accounts])
         snapshot.appendItems([.loadingIndicator])
-        await dataSource.apply(snapshot)
+        await MainActor.run {
+            dataSource.apply(snapshot)
+        }
         
         do {
             let (accounts, pagination) = try await results
@@ -210,7 +212,9 @@ class EditListAccountsViewController: UIViewController, CollectionViewController
             var snapshot = NSDiffableDataSourceSnapshot<Section, Item>()
             snapshot.appendSections([.accounts])
             snapshot.appendItems(accounts.map { .account(id: $0.id) })
-            await dataSource.apply(snapshot)
+            await MainActor.run {
+                dataSource.apply(snapshot)
+            }
             
             state = .loaded
         } catch {
@@ -221,7 +225,9 @@ class EditListAccountsViewController: UIViewController, CollectionViewController
             self.showToast(configuration: config, animated: true)
             
             state = .unloaded
-            await dataSource.apply(.init())
+            await MainActor.run {
+                dataSource.apply(.init())
+            }
         }
     }
     
@@ -236,7 +242,9 @@ class EditListAccountsViewController: UIViewController, CollectionViewController
         let origSnapshot = dataSource.snapshot()
         var snapshot = origSnapshot
         snapshot.appendItems([.loadingIndicator])
-        await dataSource.apply(snapshot)
+        await MainActor.run {
+            dataSource.apply(snapshot)
+        }
         
         do {
             let (accounts, pagination) = try await results
@@ -250,7 +258,9 @@ class EditListAccountsViewController: UIViewController, CollectionViewController
             
             var snapshot = origSnapshot
             snapshot.appendItems(accounts.map { .account(id: $0.id) })
-            await dataSource.apply(snapshot)
+            await MainActor.run {
+                dataSource.apply(snapshot)
+            }
             
             state = .loaded
         } catch {
@@ -261,7 +271,9 @@ class EditListAccountsViewController: UIViewController, CollectionViewController
             self.showToast(configuration: config, animated: true)
             
             state = .loaded
-            await dataSource.apply(origSnapshot)
+            await MainActor.run {
+                dataSource.apply(origSnapshot)
+            }
         }
     }
     

Tusker/Screens/Main/AccountSwitchingContainerViewController.swift

@@ -13,6 +13,7 @@ import ScreenCorners
 import UserAccounts
 import ComposeUI
 
+@MainActor
 protocol AccountSwitchableViewController: TuskerRootViewController {
     var isFastAccountSwitcherActive: Bool { get }
 }

Tusker/Screens/Main/MainSidebarViewController.swift

@@ -10,6 +10,7 @@ import UIKit
 import Pachyderm
 import Combine
 
+@MainActor
 protocol MainSidebarViewControllerDelegate: AnyObject {
     func sidebarRequestPresentCompose(_ sidebarViewController: MainSidebarViewController)
     func sidebar(_ sidebarViewController: MainSidebarViewController, didSelectItem item: MainSidebarViewController.Item)

Tusker/Screens/Main/MainSplitViewController.swift

@@ -11,7 +11,7 @@ import Combine
 
 class MainSplitViewController: UISplitViewController {
 
-    weak var mastodonController: MastodonController!
+    private let mastodonController: MastodonController
     
     private var sidebar: MainSidebarViewController!
     private var fastAccountSwitcher: FastAccountSwitcherViewController?
@@ -481,6 +481,7 @@ extension MainSplitViewController: MainSidebarViewControllerDelegate {
 }
 
 fileprivate extension MainSidebarViewController.Item {
+    @MainActor
     func createRootViewController(_ mastodonController: MastodonController) -> UIViewController? {
         switch self {
         case let .tab(tab):

Tusker/Screens/Main/MainTabBarViewController.swift

@@ -11,7 +11,7 @@ import ComposeUI
 
 class MainTabBarViewController: UITabBarController, UITabBarControllerDelegate {
     
-    weak var mastodonController: MastodonController!
+    private let mastodonController: MastodonController
     
     private var composePlaceholder: UIViewController!
     
@@ -207,6 +207,7 @@ extension MainTabBarViewController {
         case explore
         case myProfile
         
+        @MainActor
         func createViewController(_ mastodonController: MastodonController) -> UIViewController {
             switch self {
             case .timelines:

Tusker/Screens/Main/TuskerRootViewController.swift

@@ -83,6 +83,7 @@ enum TuskerRoute {
 //    case myProfile
 //}
 //
+@MainActor
 protocol NavigationControllerProtocol: UIViewController {
     var viewControllers: [UIViewController] { get set }
     var topViewController: UIViewController? { get }

Tusker/Screens/Notifications/NotificationsCollectionViewController.swift

@@ -15,7 +15,7 @@ import Sentry
 
 class NotificationsCollectionViewController: UIViewController, TimelineLikeCollectionViewController, CollectionViewController {
     
-    weak var mastodonController: MastodonController!
+    private let mastodonController: MastodonController
     private let filterer: Filterer
     
     private let allowedTypes: [Pachyderm.Notification.Kind]
@@ -273,8 +273,11 @@ class NotificationsCollectionViewController: UIViewController, TimelineLikeColle
         }
     }
     
-    private func dismissNotificationsInGroup(at indexPath: IndexPath) async {
-        guard case .group(let group, let collapseState, let filterState) = dataSource.itemIdentifier(for: indexPath) else {
+    private nonisolated func dismissNotificationsInGroup(at indexPath: IndexPath) async {
+        let item = await MainActor.run {
+            dataSource.itemIdentifier(for: indexPath)
+        }
+        guard case .group(let group, let collapseState, let filterState) = item else {
             return
         }
         let notifications = group.notifications
@@ -295,7 +298,9 @@ class NotificationsCollectionViewController: UIViewController, TimelineLikeColle
                 }
             })
         }
-        var snapshot = dataSource.snapshot()
+        var snapshot = await MainActor.run {
+            dataSource.snapshot()
+        }
         if dismissFailedIndices.isEmpty {
             snapshot.deleteItems([.group(group, collapseState, filterState)])
         } else if !dismissFailedIndices.isEmpty && dismissFailedIndices.count == notifications.count {

Tusker/Screens/Onboarding/InstanceSelectorTableViewController.swift

@@ -10,6 +10,7 @@ import UIKit
 import Combine
 import Pachyderm
 
+@MainActor
 protocol InstanceSelectorTableViewControllerDelegate: AnyObject {
     func didSelectInstance(url: URL)
 }
@@ -26,7 +27,7 @@ class InstanceSelectorTableViewController: UITableViewController {
     
     weak var delegate: InstanceSelectorTableViewControllerDelegate?
 
-    var dataSource: DataSource!
+    var dataSource: UITableViewDiffableDataSource<Section, Item>!
     var searchController: UISearchController!
     
     var recommendedInstances: [InstanceSelector.Instance] = []
@@ -72,7 +73,7 @@ class InstanceSelectorTableViewController: UITableViewController {
         tableView.estimatedRowHeight = 120
         createActivityIndicatorHeader()
         
-        dataSource = DataSource(tableView: tableView, cellProvider: { (tableView, indexPath, item) -> UITableViewCell? in
+        dataSource = UITableViewDiffableDataSource(tableView: tableView, cellProvider: { (tableView, indexPath, item) -> UITableViewCell? in
             switch item {
             case let .selected(_, instance):
                 let cell = tableView.dequeueReusableCell(withIdentifier: instanceCell, for: indexPath) as! InstanceTableViewCell
@@ -310,7 +311,7 @@ extension InstanceSelectorTableViewController {
         case selected
         case recommendedInstances
     }
-    enum Item: Equatable, Hashable {
+    enum Item: Equatable, Hashable, Sendable {
         case selected(URL, InstanceV1)
         case recommended(InstanceSelector.Instance)
         
@@ -337,9 +338,6 @@ extension InstanceSelectorTableViewController {
             }
         }
     }
-    class DataSource: UITableViewDiffableDataSource<Section, Item> {
-        
-    }
 }
 
 extension InstanceSelectorTableViewController: UISearchResultsUpdating {

Tusker/Screens/Onboarding/OnboardingViewController.swift

@@ -145,27 +145,24 @@ class OnboardingViewController: UINavigationController {
             throw Error.gettingAccessToken(error)
         }
         
-        // construct a temporary UserAccountInfo instance for the MastodonController to use to fetch its own account
-        let tempAccountInfo = UserAccountInfo(tempInstanceURL: instanceURL, clientID: clientID, clientSecret: clientSecret, accessToken: accessToken)
-        mastodonController.accountInfo = tempAccountInfo
+        // construct a temporary Client to use to fetch the user's account
+        let tempClient = Client(baseURL: instanceURL, accessToken: accessToken, session: .appDefault)
         
         updateStatus("Checking Credentials")
-        let ownAccount: AccountMO
+        let ownAccount: Account
         do {
             ownAccount = try await retrying("Getting own account") {
-                try await mastodonController.getOwnAccount()
+                try await tempClient.run(Client.getSelfAccount()).0
             }
         } catch {
             throw Error.gettingOwnAccount(error)
         }
         
         let accountInfo = UserAccountsManager.shared.addAccount(instanceURL: instanceURL, clientID: clientID, clientSecret: clientSecret, username: ownAccount.username, accessToken: accessToken)
-        mastodonController.accountInfo = accountInfo
-        
         self.onboardingDelegate?.didFinishOnboarding(account: accountInfo)
     }
     
-    private func retrying<T>(_ label: StaticString, action: () async throws -> T) async throws -> T {
+    private func retrying<T: Sendable>(_ label: StaticString, action: () async throws -> T) async throws -> T {
         for attempt in 0..<4 {
             do {
                 return try await action()

Tusker/Screens/Preferences/About/AboutView.swift

@@ -9,6 +9,7 @@
 import SwiftUI
 import MessageUI
 
+@MainActor
 struct AboutView: View {
     @State private var logData: Data?
     @State private var isGettingLogData = false

Tusker/Screens/Preferences/LocalAccountAvatarView.swift

@@ -32,20 +32,19 @@ struct LocalAccountAvatarView: View {
             .resizable()
             .frame(width: 30, height: 30)
             .cornerRadius(preferences.avatarStyle.cornerRadiusFraction * 30)
-            .onAppear(perform: self.loadImage)
+            .task {
+                await self.loadImage()
+            }
     }
     
-    func loadImage() {
+    func loadImage() async {
         let controller = MastodonController.getForAccount(localAccountInfo)
-        controller.getOwnAccount { (result) in
-            guard case let .success(account) = result,
-                  let avatar = account.avatar else { return }
-            _ = ImageCache.avatars.get(avatar) { (_, image) in
-                DispatchQueue.main.async {
-                    self.avatarImage = image
-                }
-            }
+        guard let account = try? await controller.getOwnAccount(),
+              let avatar = account.avatar,
+              let image = await ImageCache.avatars.get(avatar).1 else {
+            return
         }
+        self.avatarImage = image
     }
 }
 

Tusker/Screens/Preferences/WidescreenNavigationPrefsView.swift

@@ -103,6 +103,7 @@ private struct WideCapsule: Shape {
     }
 }
 
+@MainActor
 private protocol NavigationModePreview: UIView {
     init(startAnimation: PassthroughSubject<Void, Never>)
 }
@@ -118,6 +119,7 @@ private struct NavigationModeRepresentable<UIViewType: NavigationModePreview>: U
     }
 }
 
+@MainActor
 private let timingParams = UISpringTimingParameters(mass: 1, stiffness: 70, damping: 16, initialVelocity: .zero)
 
 private final class StackNavigationPreview: UIView, NavigationModePreview {

Tusker/Screens/Profile/MyProfileViewController.swift

@@ -18,13 +18,12 @@ class MyProfileViewController: ProfileViewController {
         title = "My Profile"
         tabBarItem.image = UIImage(systemName: "person.fill")
         
-        mastodonController.getOwnAccount { (result) in
-            guard case let .success(account) = result else { return }
-            
-            DispatchQueue.main.async {
-                self.accountID = account.id
-                self.setAvatarTabBarImage(account: account)
+        Task {
+            guard let account = try? await mastodonController.getOwnAccount() else {
+                return
             }
+            self.accountID = account.id
+            self.setAvatarTabBarImage(account: account)
         }
     }
     

Tusker/Screens/Profile/ProfileViewController.swift

@@ -12,7 +12,7 @@ import Combine
 
 class ProfileViewController: UIViewController, StateRestorableViewController {
     
-    weak var mastodonController: MastodonController!
+    let mastodonController: MastodonController
     
     // This property is optional because MyProfileViewController may not have the user's account ID
     // when first constructed. It should never be set to nil.

Tusker/Screens/Report/ReportStatusView.swift

@@ -8,6 +8,7 @@
 
 import SwiftUI
 
+@MainActor
 private var converter = HTMLConverter(
     font: .preferredFont(forTextStyle: .body),
     monospaceFont: UIFontMetrics.default.scaledFont(for: .monospacedSystemFont(ofSize: 17, weight: .regular)),
@@ -15,6 +16,7 @@ private var converter = HTMLConverter(
     paragraphStyle: .default
 )
 
+@MainActor
 struct ReportStatusView: View {
     let status: StatusMO
     let mastodonController: MastodonController

Tusker/Screens/Search/SearchResultsViewController.swift

@@ -15,6 +15,7 @@ fileprivate let accountCell = "accountCell"
 fileprivate let statusCell = "statusCell"
 fileprivate let hashtagCell = "hashtagCell"
 
+@MainActor
 protocol SearchResultsViewControllerDelegate: AnyObject {
     func selectedSearchResult(account accountID: String)
     func selectedSearchResult(hashtag: Hashtag)
@@ -29,7 +30,7 @@ extension SearchResultsViewControllerDelegate {
 
 class SearchResultsViewController: UIViewController, CollectionViewController {
 
-    weak var mastodonController: MastodonController!
+    let mastodonController: MastodonController
     
     weak var exploreNavigationController: UINavigationController?
     weak var delegate: SearchResultsViewControllerDelegate?
@@ -372,7 +373,7 @@ extension SearchResultsViewController {
 }
 
 extension SearchResultsViewController {
-    enum Section: Hashable {
+    enum Section: Hashable, Sendable {
         case tokenSuggestions(SearchOperatorType)
         case loadingIndicator
         case accounts
@@ -394,7 +395,7 @@ extension SearchResultsViewController {
             }
         }
     }
-    enum Item: Hashable {
+    enum Item: Hashable, Sendable {
         case tokenSuggestion(String)
         case loadingIndicator
         case account(String)

Tusker/Screens/Status Edit History/StatusEditHistoryViewController.swift

@@ -162,7 +162,7 @@ extension StatusEditHistoryViewController {
     enum Section {
         case edits
     }
-    enum Item: Hashable, Equatable {
+    enum Item: Hashable, Equatable, Sendable {
         case edit(StatusEdit, CollapseState, index: Int)
         case loadingIndicator
         

Tusker/Screens/Timeline/InstanceTimelineViewController.swift

@@ -9,6 +9,7 @@
 import UIKit
 import Pachyderm
 
+@MainActor
 protocol InstanceTimelineViewControllerDelegate: AnyObject {
     func didSaveInstance(url: URL)
     func didUnsaveInstance(url: URL)

Tusker/Screens/Timeline/TimelineViewController.swift

@@ -13,6 +13,7 @@ import Combine
 import Sentry
 #endif
 
+@MainActor
 protocol TimelineViewControllerDelegate: AnyObject {
     func timelineViewController(_ timelineViewController: TimelineViewController, willShowJumpToPresentToastWith animator: UIViewPropertyAnimator?)
     func timelineViewController(_ timelineViewController: TimelineViewController, willDismissJumpToPresentToastWith animator: UIViewPropertyAnimator?)
@@ -31,7 +32,7 @@ class TimelineViewController: UIViewController, TimelineLikeCollectionViewContro
     weak var delegate: TimelineViewControllerDelegate?
     
     let timeline: Timeline
-    weak var mastodonController: MastodonController!
+    let mastodonController: MastodonController
     private let filterer: Filterer
     
     var persistsState = false
@@ -586,7 +587,7 @@ class TimelineViewController: UIViewController, TimelineLikeCollectionViewContro
             snapshot.appendSections([.statuses])
             let items = allStatuses.map { Item.status(id: $0.id, collapseState: .unknown, filterState: .unknown) }
             snapshot.appendItems(items)
-            await dataSource.apply(snapshot, animatingDifferences: false)
+            await apply(snapshot, animatingDifferences: false)
             collectionView.contentOffset = CGPoint(x: 0, y: -collectionView.adjustedContentInset.top)
             
             stateRestorationLogger.debug("TimelineViewController: restored from timeline marker with last read ID: \(home.lastReadID)")

Tusker/Screens/Utilities/BackgroundableViewController.swift

@@ -8,6 +8,7 @@
 
 import Foundation
 
+@MainActor
 protocol BackgroundableViewController {
     func sceneDidEnterBackground()
 }

Tusker/Screens/Utilities/CollectionViewController.swift

@@ -8,6 +8,7 @@
 
 import UIKit
 
+@MainActor
 protocol CollectionViewController: UIViewController {
     var collectionView: UICollectionView! { get }
 }

Tusker/Screens/Utilities/Previewing.swift

@@ -18,12 +18,14 @@ protocol MenuActionProvider: AnyObject {
     var toastableViewController: ToastableViewController? { get }
 }
 
+@MainActor
 protocol MenuPreviewProvider: AnyObject {
     typealias PreviewProviders = (content: UIContextMenuContentPreviewProvider, actions: () -> [UIMenuElement])
     
     func getPreviewProviders(for location: CGPoint, sourceViewController: UIViewController) -> PreviewProviders?
 }
 
+@MainActor
 protocol CustomPreviewPresenting {
     func presentFromPreview(presenter: UIViewController)
 }
@@ -478,7 +480,7 @@ extension MenuActionProvider {
                     await fetchRelationship(accountID: accountID, mastodonController: mastodonController)
                 }
                 Task { @MainActor in
-                    if let relationship = await relationship.value,
+                    if let relationship = await relationship.value?.value,
                        let action = builder(relationship, mastodonController) {
                         elementHandler([action])
                     } else {
@@ -612,20 +614,25 @@ extension MenuActionProvider {
     
 }
 
-private func fetchRelationship(accountID: String, mastodonController: MastodonController) async -> RelationshipMO? {
+private func fetchRelationship(accountID: String, mastodonController: MastodonController) async -> MainThreadBox<RelationshipMO>? {
     let req = Client.getRelationships(accounts: [accountID])
     guard let (relationships, _) = try? await mastodonController.run(req),
           let r = relationships.first else {
         return nil
     }
     return await withCheckedContinuation { continuation in
-        mastodonController.persistentContainer.addOrUpdate(relationship: r, in: mastodonController.persistentContainer.viewContext) { mo in
-            continuation.resume(returning: mo)
+        DispatchQueue.main.async {
+            mastodonController.persistentContainer.addOrUpdate(relationship: r, in: mastodonController.persistentContainer.viewContext) { mo in
+                continuation.resume(returning: MainThreadBox(value: mo))
+            }
         }
     }
 }
 
 struct MenuPreviewHelper {
+    private init() {}
+    
+    @MainActor
     static func willPerformPreviewAction(animator: UIContextMenuInteractionCommitAnimating, presenter: UIViewController) {
         if let viewController = animator.previewViewController {
             animator.preferredCommitStyle = .pop

Tusker/Screens/Utilities/RefreshableViewController.swift

@@ -8,6 +8,7 @@
 
 import UIKit
 
+@MainActor
 @objc protocol RefreshableViewController {
     
     func refresh()

Tusker/Screens/Utilities/SplitNavigationController.swift

@@ -339,6 +339,7 @@ private class SplitSecondaryNavigationController: EnhancedNavigationViewControll
     
 }
 
+@MainActor
 protocol NestedResponderProvider {
     var innerResponder: UIResponder? { get }
 }

Tusker/Screens/Utilities/StateRestorableViewController.swift

@@ -8,6 +8,7 @@
 
 import UIKit
 
+@MainActor
 protocol StateRestorableViewController: UIViewController {
     func stateRestorationActivity() -> NSUserActivity?
 }

Tusker/Screens/Utilities/StatusBarTappableViewController.swift

@@ -8,6 +8,7 @@
 
 import UIKit
 
+@MainActor
 protocol StatusBarTappableViewController: UIViewController {
     func handleStatusBarTapped(xPosition: CGFloat) -> StatusBarTapActionResult
 }

Tusker/Screens/Utilities/TabBarScrollableViewController.swift

@@ -8,6 +8,7 @@
 
 import UIKit
 
+@MainActor
 protocol TabBarScrollableViewController: UIViewController {
     func tabBarScrollToTop()
 }

Tusker/Screens/Utilities/TabbedPageViewController.swift

@@ -8,6 +8,7 @@
 
 import UIKit
 
+@MainActor
 @objc protocol TabbedPageViewController {
     func selectNextPage()
     func selectPrevPage()

Tusker/Shortcuts/AppShortcutItems.swift

@@ -54,6 +54,7 @@ enum AppShortcutItem: String, CaseIterable {
 }
 
 extension AppShortcutItem {
+    @MainActor
     static func createItems(for application: UIApplication) {
         application.shortcutItems = allCases.map {
             return UIApplicationShortcutItem(type: $0.rawValue, localizedTitle: $0.title, localizedSubtitle: nil, icon: $0.icon, userInfo: nil)

Tusker/TimelineLikeController.swift

@@ -10,6 +10,7 @@ import Foundation
 import OSLog
 import Combine
 
+@MainActor
 protocol TimelineLikeControllerDelegate<TimelineItem>: AnyObject {
     associatedtype TimelineItem: Sendable
     
@@ -217,7 +218,7 @@ class TimelineLikeController<Item: Sendable> {
         }
     }
     
-    enum State: Equatable, CustomDebugStringConvertible {
+    enum State: Equatable, CustomDebugStringConvertible, Sendable {
         case notLoadedInitial
         case idle
         case restoringInitial(LoadAttemptToken, hasAddedLoadingIndicator: Bool)
@@ -360,7 +361,7 @@ class TimelineLikeController<Item: Sendable> {
         }
     }
     
-    class LoadAttemptToken: Equatable {
+    final class LoadAttemptToken: Equatable, Sendable {
         static func ==(lhs: LoadAttemptToken, rhs: LoadAttemptToken) -> Bool {
             return lhs === rhs
         }

Tusker/TuskerNavigationDelegate.swift

@@ -191,6 +191,7 @@ enum PopoverSource {
     case view(WeakHolder<UIView>)
     case barButtonItem(WeakHolder<UIBarButtonItem>)
     
+    @MainActor
     func apply(to viewController: UIViewController) {
         if let popoverPresentationController = viewController.popoverPresentationController {
             switch self {

Tusker/Views/Account Detail/LargeAccountDetailView.swift

@@ -73,8 +73,8 @@ class LargeAccountDetailView: UIView {
         if let avatar = account.avatar {
             avatarRequest = ImageCache.avatars.get(avatar) { [weak self] (_, image) in
                 guard let self = self, let image = image else { return }
-                self.avatarRequest = nil
                 DispatchQueue.main.async {
+                    self.avatarRequest = nil
                     self.avatarImageView.image = image
                 }
             }

Tusker/Views/Attachments/AttachmentView.swift

@@ -11,6 +11,7 @@ import Pachyderm
 import AVFoundation
 import TuskerComponents
 
+@MainActor
 protocol AttachmentViewDelegate: AnyObject {
     func attachmentViewGallery(startingAt index: Int) -> GalleryViewController?
     func attachmentViewPresent(_ vc: UIViewController, animated: Bool)
@@ -29,7 +30,7 @@ class AttachmentView: GIFImageView {
     var attachment: Attachment!
     var index: Int!
     
-    private var attachmentRequest: ImageCache.Request?
+    private var loadAttachmentTask: Task<Void, Never>?
     private var source: Source?
     
     private var autoplayGifs: Bool {
@@ -44,11 +45,13 @@ class AttachmentView: GIFImageView {
         
         self.attachment = attachment
         self.index = index
-        loadAttachment()
+        self.loadAttachmentTask = Task {
+            await self.loadAttachment()
+        }
     }
     
     deinit {
-        attachmentRequest?.cancel()
+        loadAttachmentTask?.cancel()
     }
     
     required init?(coder aDecoder: NSCoder) {
@@ -75,7 +78,9 @@ class AttachmentView: GIFImageView {
         gifPlaybackModeChanged()
         
         if isGrayscale != Preferences.shared.grayscaleImages {
-            self.displayImage()
+            Task {
+                await displayImage()
+            }
         }
         
         if getBadges().isEmpty != Preferences.shared.showAttachmentBadges {
@@ -106,34 +111,34 @@ class AttachmentView: GIFImageView {
         }
     }
     
-    func loadAttachment() {
+    private func loadAttachment() async {
+        let blurHashTask: Task<Void, any Error>?
         if let hash = attachment.blurHash {
-            AttachmentView.queue.async { [weak self] in
-                guard let self = self else { return }
-                
+            blurHashTask = Task {
                 guard var preview = UIImage(blurHash: hash, size: self.blurHashSize()) else {
                     return
                 }
+                try Task.checkCancellation()
                 
                 if Preferences.shared.grayscaleImages,
                    let grayscale = ImageGrayscalifier.convert(url: nil, cgImage: preview.cgImage!) {
                     preview = grayscale
                 }
+                try Task.checkCancellation()
                 
-                DispatchQueue.main.async { [weak self] in
-                    guard let self = self, self.image == nil else { return }
-                    self.image = preview
-                }
+                self.image = preview
             }
+        } else {
+            blurHashTask = nil
         }
         
         createBadgesView(getBadges())
         
         switch attachment.kind {
         case .image:
-            loadImage()
+            await loadImage()
         case .video:
-            loadVideo()
+            await loadVideo()
         case .audio:
             loadAudio()
         case .gifv:
@@ -141,6 +146,8 @@ class AttachmentView: GIFImageView {
         case .unknown:
             createUnknownLabel()
         }
+        
+        blurHashTask?.cancel()
     }
     
     private func getBadges() -> Badges {
@@ -181,66 +188,27 @@ class AttachmentView: GIFImageView {
         }
     }
     
-    func loadImage() {
-        let attachmentURL = attachment.url
-        attachmentRequest = ImageCache.attachments.get(attachmentURL) { [weak self] (data, image) in
-            guard let self = self,
-                  self.attachment.url == attachmentURL else {
-                return
-            }
-            
-            DispatchQueue.main.async {
-                self.attachmentRequest = nil
-                
-                if attachmentURL.pathExtension == "gif",
-                   let data {
-                    self.source = .gifData(attachmentURL, data, image)
-                    if self.autoplayGifs {
-                        let controller = GIFController(gifData: data)
-                        controller.attach(to: self)
-                        controller.startAnimating()
-                    } else {
-                        self.displayImage()
-                    }
-                } else if let image {
-                    self.source = .image(attachmentURL, image)
-                    self.displayImage()
-                }
+    private func loadImage() async {
+        let (data, image) = await ImageCache.attachments.get(attachment.url)
+        guard !Task.isCancelled else { return }
+        
+        if attachment.url.pathExtension == "gif",
+           let data {
+            source = .gifData(attachment.url, data, image)
+            if autoplayGifs {
+                let controller = GIFController(gifData: data)
+                controller.attach(to: self)
+                controller.startAnimating()
+            } else {
+                await displayImage()
             }
+        } else if let image {
+            source = .image(attachment.url, image)
+            await displayImage()
         }
     }
     
-    func loadVideo() {
-        if let previewURL = self.attachment.previewURL {
-            attachmentRequest = ImageCache.attachments.get(previewURL, completion: { [weak self] (_, image) in
-                guard let self, let image else { return }
-                DispatchQueue.main.async {
-                    self.attachmentRequest = nil
-                    self.source = .image(previewURL, image)
-                    self.displayImage()
-                }
-            })
-        } else {
-            let attachmentURL = self.attachment.url
-            AttachmentView.queue.async { [weak self] in
-                let asset = AVURLAsset(url: attachmentURL)
-                let generator = AVAssetImageGenerator(asset: asset)
-                generator.appliesPreferredTrackTransform = true
-                #if os(visionOS)
-                #warning("Use async AVAssetImageGenerator.image(at:)")
-                #else
-                guard let image = try? generator.copyCGImage(at: .zero, actualTime: nil) else { return }
-                UIImage(cgImage: image).prepareForDisplay { [weak self] image in
-                    DispatchQueue.main.async { [weak self] in
-                        guard let self, let image else { return }
-                        self.source = .image(attachmentURL, image)
-                        self.displayImage()
-                    }
-                }
-                #endif
-            }
-        }
-        
+    private func loadVideo() async {
         let playImageView = UIImageView(image: UIImage(systemName: "play.circle.fill"))
         playImageView.translatesAutoresizingMaskIntoConstraints = false
         addSubview(playImageView)
@@ -250,9 +218,40 @@ class AttachmentView: GIFImageView {
             playImageView.centerXAnchor.constraint(equalTo: centerXAnchor),
             playImageView.centerYAnchor.constraint(equalTo: centerYAnchor),
         ])
+        
+        if let previewURL = attachment.previewURL {
+            guard let image = await ImageCache.attachments.get(previewURL).1,
+                  !Task.isCancelled else {
+                return
+            }
+            
+            source = .image(previewURL, image)
+            await displayImage()
+        } else {
+            let asset = AVURLAsset(url: attachment.url)
+            let generator = AVAssetImageGenerator(asset: asset)
+            generator.appliesPreferredTrackTransform = true
+            let image: CGImage?
+            #if os(visionOS)
+            image = try? await generator.image(at: .zero).image
+            #else
+            if #available(iOS 16.0, *) {
+                image = try? await generator.image(at: .zero).image
+            } else {
+                image = try? generator.copyCGImage(at: .zero, actualTime: nil)
+            }
+            #endif
+            guard let image,
+                  let prepared = await UIImage(cgImage: image).byPreparingForDisplay(),
+                  !Task.isCancelled else {
+                return
+            }
+            source = .image(attachment.url, prepared)
+            await displayImage()
+        }
     }
     
-    func loadAudio() {
+    private func loadAudio() {
         let label = UILabel()
         label.text = "Audio Only"
         let playImageView = UIImageView(image: UIImage(systemName: "play.circle.fill"))
@@ -273,23 +272,8 @@ class AttachmentView: GIFImageView {
         ])
     }
     
-    func loadGifv() {
-        let attachmentURL = self.attachment.url
-        let asset = AVURLAsset(url: attachmentURL)
-        AttachmentView.queue.async {
-            let generator = AVAssetImageGenerator(asset: asset)
-            generator.appliesPreferredTrackTransform = true
-            #if os(visionOS)
-            #warning("Use async AVAssetImageGenerator.image(at:)")
-            #else
-            guard let image = try? generator.copyCGImage(at: .zero, actualTime: nil) else { return }
-            DispatchQueue.main.async {
-                self.source = .cgImage(attachmentURL, image)
-                self.displayImage()
-            }
-            #endif
-        }
-        
+    private func loadGifv() {
+        let asset = AVURLAsset(url: attachment.url)
         let gifvView = GifvAttachmentView(asset: asset, gravity: .resizeAspectFill)
         self.gifvView = gifvView
         gifvView.translatesAutoresizingMaskIntoConstraints = false
@@ -305,7 +289,7 @@ class AttachmentView: GIFImageView {
         ])
     }
     
-    func createUnknownLabel() {
+    private func createUnknownLabel() {
         backgroundColor = .appSecondaryBackground
         let label = UILabel()
         label.text = "Unknown Attachment Type"
@@ -324,8 +308,7 @@ class AttachmentView: GIFImageView {
         ])
     }
     
-    @MainActor
-    private func displayImage() {
+    private func displayImage() async {
         isGrayscale = Preferences.shared.grayscaleImages
         
         switch source {
@@ -334,12 +317,7 @@ class AttachmentView: GIFImageView {
             
         case let .image(url, sourceImage):
             if isGrayscale {
-                ImageGrayscalifier.queue.async { [weak self] in
-                    let grayscale = ImageGrayscalifier.convert(url: url, image: sourceImage)
-                    DispatchQueue.main.async { [weak self] in
-                        self?.image = grayscale
-                    }
-                }
+                self.image = await ImageGrayscalifier.convert(url: url, image: sourceImage)
             } else {
                 self.image = sourceImage
             }
@@ -347,26 +325,16 @@ class AttachmentView: GIFImageView {
         case let .gifData(url, _, sourceImage):
             if isGrayscale,
                let sourceImage {
-                ImageGrayscalifier.queue.async { [weak self] in
-                    let grayscale = ImageGrayscalifier.convert(url: url, image: sourceImage)
-                    DispatchQueue.main.async { [weak self] in
-                        self?.image = grayscale
-                    }
-                }
+                self.image = await ImageGrayscalifier.convert(url: url, image: sourceImage)
             } else {
                 self.image = sourceImage
             }
             
         case let .cgImage(url, cgImage):
             if isGrayscale {
-                ImageGrayscalifier.queue.async { [weak self] in
-                    let grayscale = ImageGrayscalifier.convert(url: url, cgImage: cgImage)
-                    DispatchQueue.main.async { [weak self] in
-                        self?.image = grayscale
-                    }
-                }
+                self.image = await ImageGrayscalifier.convert(url: url, cgImage: cgImage)
             } else {
-                image = UIImage(cgImage: cgImage)
+                self.image = UIImage(cgImage: cgImage)
             }
         }
     }

Tusker/Views/BaseEmojiLabel.swift

@@ -11,12 +11,8 @@ import Pachyderm
 import WebURLFoundationExtras
 
 private let emojiRegex = try! NSRegularExpression(pattern: ":(\\w+):", options: [])
-#if os(visionOS)
-private let imageScale: CGFloat = 2
-#else
-private let imageScale = UIScreen.main.scale
-#endif
 
+@MainActor
 protocol BaseEmojiLabel: AnyObject {
     var emojiIdentifier: AnyHashable? { get set }
     var emojiRequests: [ImageCache.Request] { get set }
@@ -47,10 +43,15 @@ extension BaseEmojiLabel {
         
         // Based on https://github.com/ReticentJohn/Amaroq/blob/7c5b7088eb9fd1611dcb0f47d43bf8df093e142c/DireFloof/InlineImageHelpers.m
         let adjustedCapHeight = emojiFont.capHeight - 1
+        #if os(visionOS)
+        let screenScale: CGFloat = 2
+        #else
+        let screenScale = UIScreen.main.scale
+        #endif
+        @Sendable
         func emojiImageSize(_ image: UIImage) -> CGSize {
             var imageSizeMatchingFontSize = CGSize(width: image.size.width * (adjustedCapHeight / image.size.height), height: adjustedCapHeight)
-            var scale: CGFloat = 1.4
-            scale *= imageScale
+            let scale = 1.4 * screenScale
             imageSizeMatchingFontSize = CGSize(width: imageSizeMatchingFontSize.width * scale, height: imageSizeMatchingFontSize.height * scale)
             return imageSizeMatchingFontSize
         }
@@ -80,7 +81,7 @@ extension BaseEmojiLabel {
                    let cgImage = thumbnail.cgImage {
                     // the thumbnail API takes a pixel size and returns an image with scale 1, but we want the actual screen scale, so convert
                     // see FB12187798
-                    emojiImages[emoji.shortcode] = UIImage(cgImage: cgImage, scale: imageScale, orientation: .up)
+                    emojiImages[emoji.shortcode] = UIImage(cgImage: cgImage, scale: screenScale, orientation: .up)
                 }
             } else {
                 // otherwise, perform the network request
@@ -93,7 +94,7 @@ extension BaseEmojiLabel {
                     }
                     image.prepareThumbnail(of: emojiImageSize(image)) { thumbnail in
                         guard let thumbnail = thumbnail?.cgImage,
-                              case let rescaled = UIImage(cgImage: thumbnail, scale: imageScale, orientation: .up),
+                              case let rescaled = UIImage(cgImage: thumbnail, scale: screenScale, orientation: .up),
                               let transformedImage = ImageGrayscalifier.convertIfNecessary(url: URL(emoji.url)!, image: rescaled) else {
                             group.leave()
                             return

Tusker/Views/CachedImageView.swift

@@ -90,8 +90,7 @@ class CachedImageView: UIImageView {
                 return
             }
             try Task.checkCancellation()
-            // TODO: check that this isn't on the main thread
-            guard let transformedImage = ImageGrayscalifier.convertIfNecessary(url: url, image: image) else {
+            guard let transformedImage = await ImageGrayscalifier.convertIfNecessary(url: url, image: image) else {
                 return
             }
             try Task.checkCancellation()

Tusker/Views/ContentTextView.swift

@@ -93,7 +93,9 @@ class ContentTextView: LinkTextView, BaseEmojiLabel {
         updateLinkUnderlineStyle()
     }
     
-    private func updateLinkUnderlineStyle(preference: Bool = Preferences.shared.underlineTextLinks) {
+    @MainActor
+    private func updateLinkUnderlineStyle(preference: Bool? = nil) {
+        let preference = preference ?? Preferences.shared.underlineTextLinks
         if UIAccessibility.buttonShapesEnabled || preference {
             linkTextAttributes[.underlineStyle] = NSUnderlineStyle.single.rawValue
         } else {

Tusker/Views/Instance Cell/InstanceTableViewCell.swift

@@ -19,8 +19,11 @@ class InstanceTableViewCell: UITableViewCell {
     var instance: InstanceV1?
     var selectorInstance: InstanceSelector.Instance?
     
-    var thumbnailURL: URL?
-    var thumbnailRequest: ImageCache.Request?
+    private var thumbnailTask: Task<Void, Never>?
+    
+    deinit {
+        thumbnailTask?.cancel()
+    }
     
     override func awakeFromNib() {
         super.awakeFromNib()
@@ -68,20 +71,19 @@ class InstanceTableViewCell: UITableViewCell {
     
     private func updateThumbnail(url: URL) {
         thumbnailImageView.image = nil
-        thumbnailURL = url
-        thumbnailRequest = ImageCache.attachments.get(url) { [weak self] (_, image) in
-            guard let self = self, self.thumbnailURL == url, let image = image else { return }
-            self.thumbnailRequest = nil
-            DispatchQueue.main.async {
-                self.thumbnailImageView.image = image
+        thumbnailTask = Task {
+            guard let image = await ImageCache.attachments.get(url).1,
+                  !Task.isCancelled else {
+                return
             }
+            thumbnailImageView.image = image
         }
     }
     
     override func prepareForReuse() {
         super.prepareForReuse()
         
-        thumbnailRequest?.cancel()
+        thumbnailTask?.cancel()
         instance = nil
         selectorInstance = nil
     }

Tusker/Views/MultiSourceEmojiLabel.swift

@@ -24,7 +24,7 @@ class MultiSourceEmojiLabel: UILabel, BaseEmojiLabel {
         
         var attributedStrings = pairs.map { NSAttributedString(string: $0.0) }
         
-        let recombine = { [weak self] in
+        let recombine: @MainActor @Sendable () -> Void = { [weak self] in
             if let self,
                let combiner = self.combiner {
                 self.attributedText = combiner(attributedStrings)

Tusker/Views/Profile Header/ProfileFieldsView.swift

@@ -53,7 +53,9 @@ class ProfileFieldsView: UIView {
     
     private func commonInit() {
         boundsObservation = observe(\.bounds, changeHandler: { [unowned self] _, _ in
-            self.setNeedsUpdateConstraints()
+            MainActor.runUnsafely {
+                self.setNeedsUpdateConstraints()
+            }
         })
         
         #if os(visionOS)

Tusker/Views/Profile Header/ProfileHeaderView.swift

@@ -9,6 +9,7 @@
 import UIKit
 import Pachyderm
 
+@MainActor
 protocol ProfileHeaderViewDelegate: TuskerNavigationDelegate, MenuActionProvider {
     func profileHeader(_ headerView: ProfileHeaderView, selectedPageChangedTo newPage: ProfileViewController.Page)
 }
@@ -41,8 +42,7 @@ class ProfileHeaderView: UIView {
     
     var accountID: String!
     
-    private var avatarRequest: ImageCache.Request?
-    private var headerRequest: ImageCache.Request?
+    private var imagesTask: Task<Void, Never>?
     
     private var isGrayscale = false
     private var followButtonMode = FollowButtonMode.follow {
@@ -55,8 +55,7 @@ class ProfileHeaderView: UIView {
     }
     
     deinit {
-        avatarRequest?.cancel()
-        headerRequest?.cancel()
+        imagesTask?.cancel()
     }
     
     override func awakeFromNib() {
@@ -133,7 +132,12 @@ class ProfileHeaderView: UIView {
         usernameLabel.text = "@\(account.acct)"
         lockImageView.isHidden = !account.locked
         
-        updateImages(account: account)
+        imagesTask?.cancel()
+        let avatar = account.avatar
+        let header = account.header
+        imagesTask = Task {
+            await updateImages(avatar: avatar, header: header)
+        }
         
         moreButton.menu = UIMenu(title: "", image: nil, identifier: nil, options: [], children: delegate?.actionsForProfile(accountID: accountID, source: .view(moreButton), fetchRelationship: false) ?? [])
         
@@ -285,50 +289,41 @@ class ProfileHeaderView: UIView {
         displayNameLabel.updateForAccountDisplayName(account: account)
         
         if isGrayscale != Preferences.shared.grayscaleImages {
-            updateImages(account: account)
+            isGrayscale = Preferences.shared.grayscaleImages
+            imagesTask?.cancel()
+            let avatar = account.avatar
+            let header = account.header
+            imagesTask = Task {
+                await updateImages(avatar: avatar, header: header)
+            }
         }
     }
     
-    private func updateImages(account: AccountMO) {
-        isGrayscale = Preferences.shared.grayscaleImages
-        
-        let accountID = account.id
-        if let avatarURL = account.avatar {
-            // always load original for avatars, because ImageCache.avatars stores them scaled-down in memory
-            avatarRequest = ImageCache.avatars.get(avatarURL, loadOriginal: true) { [weak self] (_, image) in
-                guard let self = self,
-                      let image = image,
-                      self.accountID == accountID,
-                      let transformedImage = ImageGrayscalifier.convertIfNecessary(url: avatarURL, image: image) else {
-                    DispatchQueue.main.async {
-                        self?.avatarRequest = nil
-                    }
+    private nonisolated func updateImages(avatar: URL?, header: URL?) async {
+        await withTaskGroup(of: Void.self) { group in
+            group.addTask {
+                guard let avatar,
+                      let image = await ImageCache.avatars.get(avatar, loadOriginal: true).1,
+                      let transformedImage = await ImageGrayscalifier.convertIfNecessary(url: avatar, image: image),
+                      !Task.isCancelled else {
                     return
                 }
-                
-                DispatchQueue.main.async {
-                    self.avatarRequest = nil
+                await MainActor.run {
                     self.avatarImageView.image = transformedImage
                 }
             }
-        }
-        if let header = account.header {
-            headerRequest = ImageCache.headers.get(header) { [weak self] (_, image) in
-                guard let self = self,
-                      let image = image,
-                      self.accountID == accountID,
-                      let transformedImage = ImageGrayscalifier.convertIfNecessary(url: header, image: image) else {
-                    DispatchQueue.main.async {
-                        self?.headerRequest = nil
-                    }
+            group.addTask {
+                guard let header,
+                      let image = await ImageCache.avatars.get(header, loadOriginal: true).1,
+                      let transformedImage = await ImageGrayscalifier.convertIfNecessary(url: header, image: image),
+                      !Task.isCancelled else {
                     return
                 }
-                
-                DispatchQueue.main.async {
-                    self.headerRequest = nil
+                await MainActor.run {
                     self.headerImageView.image = transformedImage
                 }
             }
+            await group.waitForAll()
         }
     }
     

Tusker/Views/Status/StatusContentContainer.swift

@@ -179,13 +179,16 @@ extension StatusContentContainer {
 }
 
 private extension UIView {
-    func observeIsHidden(_ f: @escaping () -> Void) -> NSKeyValueObservation {
+    func observeIsHidden(_ f: @escaping @Sendable @MainActor () -> Void) -> NSKeyValueObservation {
         self.observe(\.isHidden) { _, _ in
-            f()
+            MainActor.runUnsafely {
+                f()
+            }
         }
     }
 }
 
+@MainActor
 protocol StatusContentView: UIView {
     var statusContentFillsHorizontally: Bool { get }
     func estimateHeight(effectiveWidth: CGFloat) -> CGFloat

Tusker/Views/Toast/ToastConfiguration.swift

@@ -20,8 +20,8 @@ struct ToastConfiguration {
     var title: String
     var subtitle: String?
     var actionTitle: String?
-    var action: ((ToastView) -> Void)?
-    var longPressAction: ((ToastView) -> Void)?
+    var action: (@MainActor (ToastView) -> Void)?
+    var longPressAction: (@MainActor (ToastView) -> Void)?
     var edgeSpacing: CGFloat = 8
     var edge: Edge = .automatic
     var dismissOnScroll = true
@@ -42,7 +42,7 @@ struct ToastConfiguration {
 }
 
 extension ToastConfiguration {
-    init(from error: Error, with title: String, in viewController: TuskerNavigationDelegate, retryAction: ((ToastView) -> Void)?) {
+    init(from error: Error, with title: String, in viewController: TuskerNavigationDelegate, retryAction: (@MainActor (ToastView) -> Void)?) {
         self.init(title: title)
         // localizedDescription is statically dispatched, so we need to call it after the downcast
         if let error = error as? Pachyderm.Client.Error {
@@ -73,7 +73,7 @@ extension ToastConfiguration {
         }
     }
     
-    init(from error: Error, with title: String, in viewController: TuskerNavigationDelegate, retryAction: @escaping @MainActor (ToastView) async -> Void) {
+    init(from error: Error, with title: String, in viewController: TuskerNavigationDelegate, retryAction: @Sendable @escaping @MainActor (ToastView) async -> Void) {
         self.init(from: error, with: title, in: viewController) { toast in
             Task {
                 await retryAction(toast)