Defaults witout MainActor

Author: NikSativa

Source/Defaults.swift

@@ -1,9 +1,6 @@
 import Combine
 import Foundation
 
-#if swift(>=6.0)
-@MainActor
-#endif
 /// A property wrapper that stores and observes values in `UserDefaults` with support for encoding and decoding.
 ///
 /// `Defaults` synchronizes with `UserDefaults`, enabling automatic storage, retrieval, and observation
@@ -93,16 +90,7 @@ public final class Defaults<Value: Codable & Equatable> {
         self.decoderGenerator = decoder ?? { .init() }
 
         self.defaultsObserver = .init(key: key, userDefaults: userDefaults)
-        defaultsObserver.updateHandler = { [weak self] _ in
-            self?.syncMain()
-        }
-
-        // sometimes KVO is not working
-        self.notificationToken = NotificationCenter.default.addObserver(forName: UserDefaults.didChangeNotification,
-                                                                        object: userDefaults,
-                                                                        queue: .main) { [weak self] _ in
-            self?.syncMain()
-        }
+        subscribe()
     }
 
     deinit {
@@ -111,6 +99,24 @@ public final class Defaults<Value: Codable & Equatable> {
         }
     }
 
+    private func subscribe() {
+        // swiftformat:disable:next all
+        let unsafeSync = UnsafeSendable({ [weak self] in
+            self?.syncMain()
+        })
+
+        defaultsObserver.updateHandler = { [unsafeSync] _ in
+            unsafeSync.value()
+        }
+
+        // sometimes KVO is not working
+        notificationToken = NotificationCenter.default.addObserver(forName: UserDefaults.didChangeNotification,
+                                                                   object: userDefaults,
+                                                                   queue: .main) { [unsafeSync] _ in
+            unsafeSync.value()
+        }
+    }
+
     private nonisolated func syncMain() {
         assert(Thread.isMainThread, "Should be used only in main thread")
 
@@ -197,10 +203,6 @@ public extension Defaults where Value: ExpressibleByDictionaryLiteral, Value.Key
     }
 }
 
-#if swift(>=6.0)
-extension Defaults: @unchecked Sendable {}
-#endif
-
 private final class DefaultsObserver: NSObject {
     private let userDefaults: UserDefaults
     private let key: String
@@ -223,7 +225,7 @@ private final class DefaultsObserver: NSObject {
         userDefaults.removeObserver(self, forKeyPath: key, context: nil)
     }
 
-    override public func observeValue(forKeyPath keyPath: String?, of object: Any?, change: [NSKeyValueChangeKey: Any]?, context: UnsafeMutableRawPointer?) {
+    override func observeValue(forKeyPath keyPath: String?, of object: Any?, change: [NSKeyValueChangeKey: Any]?, context: UnsafeMutableRawPointer?) {
         guard let change, keyPath == key else {
             return
         }
@@ -239,20 +241,18 @@ private final class DefaultsObserver: NSObject {
     }
 }
 
-#if swift(>=6.0)
-extension DefaultsObserver: @unchecked Sendable {}
-
-private struct UnsafeSendable<T>: @unchecked Sendable {
+private struct UnsafeSendable<T> {
     let value: T
 }
-#else
-struct UnsafeSendable<T> {
-    let value: T
-}
-#endif
 
 extension UnsafeSendable {
     init(_ value: T) {
         self.value = value
     }
 }
+
+#if swift(>=6.0)
+extension Defaults: @unchecked Sendable {}
+extension DefaultsObserver: @unchecked Sendable {}
+extension UnsafeSendable: @unchecked Sendable {}
+#endif

Source/Storage.swift

@@ -124,8 +124,7 @@ public extension Storage {
 /// - Returns: A new `Storage` that reflects the combined state.
 @available(macOS 13, iOS 16, tvOS 16.0, watchOS 9.0, *)
 @inline(__always)
-public func zip<Value>(storages: [any Storage<Value>]) -> some Storage<Value>
-where Value: ExpressibleByNilLiteral & Equatable {
+public func zip<Value: ExpressibleByNilLiteral & Equatable>(storages: [any Storage<Value>]) -> some Storage<Value> {
     return StorageComposition(storages: storages).toAny()
 }
 
@@ -137,7 +136,6 @@ where Value: ExpressibleByNilLiteral & Equatable {
 @available(macOS, deprecated: 13)
 @available(iOS, deprecated: 16)
 @inline(__always)
-public func zip<Value>(storages: [AnyStorage<Value>]) -> some Storage<Value>
-where Value: ExpressibleByNilLiteral & Equatable {
+public func zip<Value: ExpressibleByNilLiteral & Equatable>(storages: [AnyStorage<Value>]) -> some Storage<Value> {
     return StorageComposition(storages: storages).toAny()
 }

Source/StorageComposition.swift

@@ -13,7 +13,7 @@ internal final class StorageComposition<Value: ExpressibleByNilLiteral & Equatab
     /// A publisher that emits the current value and any future changes across the combined storages.
     ///
     /// Use this publisher to observe updates from any of the underlying storages.
-    public private(set) lazy var eventier: ValuePublisher<Value> = subject.eraseToAnyPublisher()
+    private(set) lazy var eventier: ValuePublisher<Value> = subject.eraseToAnyPublisher()
 
     private let storages: [AnyStorage<Value>]
     private var observers: [AnyCancellable] = []

Source/Storages/FileStorage.swift

@@ -7,8 +7,7 @@ import Foundation
 /// through Combine publishers.
 ///
 /// The file is stored in the app's Caches directory under a "Storages" folder.
-public final class FileStorage<Value>: Storage
-where Value: ExpressibleByNilLiteral & Codable {
+public final class FileStorage<Value: ExpressibleByNilLiteral & Codable>: Storage {
     private lazy var subject: ValueSubject<Value> = .init(get())
     /// A publisher that emits the current value and all subsequent updates.
     ///

Source/Storages/UserDefaultsStorage.swift

@@ -8,8 +8,7 @@ import Foundation
 /// Use this class to manage lightweight settings, preferences, or any other persistable data.
 ///
 /// - Note: The `Value` must conform to `Codable` and `ExpressibleByNilLiteral`.
-public final class UserDefaultsStorage<Value>: Storage
-where Value: ExpressibleByNilLiteral & Codable {
+public final class UserDefaultsStorage<Value: ExpressibleByNilLiteral & Codable>: Storage {
     private lazy var subject: ValueSubject<Value> = .init(get())
     /// A publisher that emits the current value and all subsequent changes.
     ///

Tests/DefaultsTests.swift

@@ -3,7 +3,6 @@ import Foundation
 import StorageKit
 import XCTest
 
-@MainActor
 final class DefaultsTests: XCTestCase {
     fileprivate struct Custom: Codable, Equatable {
         let value: Int
@@ -89,14 +88,13 @@ final class DefaultsTests: XCTestCase {
 }
 
 extension DefaultsTests {
-    private func run_test_value_type<T>(_ type: T.Type,
-                                        defaultValue: T,
-                                        values: [T],
-                                        isPropertyListType: Bool = true, // UserDefaults error: Attempt to insert non-property list object
-                                        userDefaults: UserDefaults?,
-                                        file: StaticString = #filePath,
-                                        line: UInt = #line)
-    where T: Codable & Equatable & SafeSendable {
+    private func run_test_value_type<T: Codable & Equatable & SafeSendable>(_: T.Type,
+                                                                            defaultValue: T,
+                                                                            values: [T],
+                                                                            isPropertyListType: Bool = true, // UserDefaults error: Attempt to insert non-property list object
+                                                                            userDefaults: UserDefaults?,
+                                                                            file: StaticString = #filePath,
+                                                                            line: UInt = #line) {
         let key = String(describing: T.self)
         let userDefaults: UserDefaults = userDefaults ?? .init(suiteName: "DefaultsTests_\(key)")!
         // clean user defaults before use