Minor tweaks

.swiftlint.yml

@@ -1,5 +1,4 @@
 only_rules:
-  - anyobject_protocol
   - array_init
   - block_based_kvo
   - class_delegate_protocol
@@ -10,6 +9,7 @@ only_rules:
   - collection_alignment
   - colon
   - comma
+  - comma_inheritance
   - compiler_protocol_init
   - computed_accessors_order
   - conditional_returns_on_newline
@@ -105,6 +105,7 @@ only_rules:
   - required_enum_case
   - return_arrow_whitespace
   - return_value_from_void_function
+  - self_binding
   - self_in_property_initialization
   - shorthand_operator
   - sorted_first_last
@@ -136,9 +137,9 @@ only_rules:
   - unused_setter_value
   - valid_ibinspectable
   - vertical_parameter_alignment
-  - vertical_parameter_alignment_on_call
   - vertical_whitespace_closing_braces
   - vertical_whitespace_opening_braces
+  - void_function_in_ternary
   - void_return
   - xct_specific_matcher
   - yoda_condition
@@ -192,3 +193,6 @@ custom_rules:
   final_class:
     regex: '^class [a-zA-Z\d]+[^{]+\{'
     message: 'Classes should be marked as final whenever possible. If you actually need it to be subclassable, just add `// swiftlint:disable:next final_class`.'
+  no_alignment_center:
+    regex: '\b\(alignment: .center\b'
+    message: 'This alignment is the default.'

Sources/Defaults/Defaults+AnySerializable.swift

@@ -191,7 +191,7 @@ extension Defaults.AnySerializable: ExpressibleByDictionaryLiteral {
 	}
 }
 
-extension Defaults.AnySerializable: _DefaultsOptionalType {
+extension Defaults.AnySerializable: _DefaultsOptionalProtocol {
 	// Since `nil` cannot be assigned to `Any`, we use `Void` instead of `nil`.
 	public var isNil: Bool { value is Void }
 }

Sources/Defaults/Defaults.swift

@@ -53,7 +53,7 @@ public enum Defaults {
 
 			super.init(name: key, suite: suite)
 
-			if (defaultValue as? _DefaultsOptionalType)?.isNil == true {
+			if (defaultValue as? _DefaultsOptionalProtocol)?.isNil == true {
 				return
 			}
 

Sources/Defaults/SwiftUI.swift

@@ -4,8 +4,10 @@ import Combine
 
 @available(macOS 10.15, iOS 13.0, tvOS 13.0, watchOS 6.0, *)
 extension Defaults {
+	@MainActor
 	final class Observable<Value: Serializable>: ObservableObject {
 		private var cancellable: AnyCancellable?
+		private var task: Task<Void, Never>?
 		private let key: Defaults.Key<Value>
 
 		let objectWillChange = ObservableObjectPublisher()
@@ -21,16 +23,34 @@ extension Defaults {
 		init(_ key: Key<Value>) {
 			self.key = key
 
-			self.cancellable = Defaults.publisher(key, options: [.prior])
-				.sink { [weak self] change in
-					guard change.isPrior else {
-						return
-					}
+			// We only use this on the latest OSes (as of adding this) since the backdeploy library has a lot of bugs.
+			if #available(macOS 13, iOS 16, tvOS 16, watchOS 9, *) {
+				// The `@MainActor` is important as the `.send()` method doesn't inherit the `@MainActor` from the class.
+				self.task = .detached(priority: .userInitiated) { @MainActor [weak self] in
+					for await _ in Defaults.events(key) {
+						guard let self else {
+							return
+						}
 
-					DispatchQueue.mainSafeAsync {
-						self?.objectWillChange.send()
+						self.objectWillChange.send()
 					}
 				}
+			} else {
+				self.cancellable = Defaults.publisher(key, options: [.prior])
+					.sink { [weak self] change in
+						guard change.isPrior else {
+							return
+						}
+
+						Task { @MainActor in
+							self?.objectWillChange.send()
+						}
+					}
+			}
+		}
+
+		deinit {
+			task?.cancel()
 		}
 
 		/**
@@ -77,7 +97,7 @@ public struct Default<Value: Defaults.Serializable>: DynamicProperty {
 	*/
 	public init(_ key: Defaults.Key<Value>) {
 		self.key = key
-		self.observable = Defaults.Observable(key)
+		self.observable = .init(key)
 	}
 
 	public var wrappedValue: Value {
@@ -178,7 +198,7 @@ extension Defaults {
 
 		public init(key: Defaults.Key<Bool>, @ViewBuilder label: @escaping () -> Label) {
 			self.label = label
-			self.observable = Defaults.Observable(key)
+			self.observable = .init(key)
 		}
 
 		public var body: some View {
@@ -194,7 +214,7 @@ extension Defaults {
 extension Defaults.Toggle<Text> {
 	public init(_ title: some StringProtocol, key: Defaults.Key<Bool>) {
 		self.label = { Text(title) }
-		self.observable = Defaults.Observable(key)
+		self.observable = .init(key)
 	}
 }
 
@@ -209,6 +229,29 @@ extension Defaults.Toggle {
 	}
 }
 
+@available(macOS 10.15, iOS 13.0, tvOS 13.0, watchOS 6.0, *)
+extension Defaults {
+	// TODO: Expose this publicly at some point.
+	private static func events<Value: Serializable>(
+		_ key: Defaults.Key<Value>,
+		initial: Bool = true
+	) -> AsyncStream<Value> { // TODO: Make this `some AsyncSequence<Value>` when Swift 6 is out.
+		.init { continuation in
+			let observation = UserDefaultsKeyObservation(object: key.suite, key: key.name) { change in
+				// TODO: Use the `.deserialize` method directly.
+				let value = KeyChange(change: change, defaultValue: key.defaultValue).newValue
+				continuation.yield(value)
+			}
+
+			observation.start(options: initial ? [.initial] : [])
+
+			continuation.onTermination = { _ in
+				observation.invalidate()
+			}
+		}
+	}
+}
+
 @available(macOS 10.15, iOS 13.0, tvOS 13.0, watchOS 6.0, *)
 @propertyWrapper
 private struct ViewStorage<Value>: DynamicProperty {

Sources/Defaults/UserDefaults.swift

@@ -10,7 +10,7 @@ extension UserDefaults {
 	}
 
 	 func _set<Value: Defaults.Serializable>(_ key: String, to value: Value) {
-		if (value as? _DefaultsOptionalType)?.isNil == true {
+		if (value as? _DefaultsOptionalProtocol)?.isNil == true {
 			removeObject(forKey: key)
 			return
 		}

Sources/Defaults/Utilities.swift

@@ -20,7 +20,7 @@ extension Decodable {
 }
 
 
-final class ObjectAssociation<T: Any> {
+final class ObjectAssociation<T> {
 	subscript(index: AnyObject) -> T? {
 		get {
 			objc_getAssociatedObject(index, Unmanaged.passUnretained(self).toOpaque()) as! T?
@@ -124,32 +124,18 @@ A protocol for making generic type constraints of optionals.
 
 - Note: It's intentionally not including `associatedtype Wrapped` as that limits a lot of the use-cases.
 */
-public protocol _DefaultsOptionalType: ExpressibleByNilLiteral {
+public protocol _DefaultsOptionalProtocol: ExpressibleByNilLiteral {
 	/**
 	This is useful as you cannot compare `_OptionalType` to `nil`.
 	*/
 	var isNil: Bool { get }
 }
 
-extension Optional: _DefaultsOptionalType {
+extension Optional: _DefaultsOptionalProtocol {
 	public var isNil: Bool { self == nil }
 }
 
 
-extension DispatchQueue {
-	/**
-	Performs the `execute` closure immediately if we're on the main thread or asynchronously puts it on the main thread otherwise.
-	*/
-	static func mainSafeAsync(execute work: @escaping () -> Void) {
-		if Thread.isMainThread {
-			work()
-		} else {
-			main.async(execute: work)
-		}
-	}
-}
-
-
 extension Sequence {
 	/**
 	Returns an array containing the non-nil elements.

Tests/DefaultsTests/DefaultsCodableEnumTests.swift

@@ -2,7 +2,7 @@ import Foundation
 import Defaults
 import XCTest
 
-private enum FixtureCodableEnum: String, Defaults.Serializable & Codable & Hashable {
+private enum FixtureCodableEnum: String, Hashable, Codable, Defaults.Serializable {
 	case tenMinutes = "10 Minutes"
 	case halfHour = "30 Minutes"
 	case oneHour = "1 Hour"

Tests/DefaultsTests/DefaultsNSSecureCodingTests.swift

@@ -349,7 +349,12 @@ final class DefaultsNSSecureCodingTests: XCTestCase {
 				.collect(expectedArray.count)
 				.sink { result in
 					print("Result array: \(result)")
-					result == expectedArray ? expect.fulfill() : XCTFail("Expected Array is not matched")
+
+					if result == expectedArray {
+						expect.fulfill()
+					} else {
+						XCTFail("Expected Array is not matched")
+					}
 				}
 
 			inputArray.forEach {
@@ -378,7 +383,12 @@ final class DefaultsNSSecureCodingTests: XCTestCase {
 				.collect(expectedArray.count)
 				.sink { result in
 					print("Result array: \(result)")
-					result == expectedArray ? expect.fulfill() : XCTFail("Expected Array is not matched")
+
+					if result == expectedArray {
+						expect.fulfill()
+					} else {
+						XCTFail("Expected Array is not matched")
+					}
 				}
 
 			inputArray.forEach {

Tests/DefaultsTests/DefaultsTests.swift

@@ -499,7 +499,12 @@ final class DefaultsTests: XCTestCase {
 			.collect(expectedArray.count)
 			.sink { result in
 				print("Result array: \(result)")
-				result == expectedArray ? expect.fulfill() : XCTFail("Expected Array is not matched")
+
+				if result == expectedArray {
+					expect.fulfill()
+				} else {
+					XCTFail("Expected Array is not matched")
+				}
 			}
 
 		inputArray.forEach {
@@ -527,7 +532,12 @@ final class DefaultsTests: XCTestCase {
 			.collect(expectedArray.count)
 			.sink { result in
 				print("Result array: \(result)")
-				result == expectedArray ? expect.fulfill() : XCTFail("Expected Array is not matched")
+
+				if result == expectedArray {
+					expect.fulfill()
+				} else {
+					XCTFail("Expected Array is not matched")
+				}
 			}
 
 		inputArray.forEach {