Support swift 6

.editorconfig

@@ -0,0 +1,9 @@
+# editorconfig.org
+
+root = true
+
+[*]
+indent_style = space
+indent_size = 4
+trim_trailing_whitespace = true
+insert_final_newline = true

Package.swift

@@ -1,36 +1,28 @@
-// swift-tools-version:5.1
+// swift-tools-version:6.0
 // The swift-tools-version declares the minimum version of Swift required to build this package.
 
 import PackageDescription
 
-#if swift(>=5.9)
-let platforms: [PackageDescription.SupportedPlatform] = [.macOS(.v10_13), .iOS(.v12), .watchOS(.v4), .tvOS(.v12)]
-#elseif swift(>=5.7)
-let platforms: [PackageDescription.SupportedPlatform] = [.macOS(.v10_13), .iOS(.v11), .watchOS(.v4), .tvOS(.v11)]
-#elseif swift(>=5.0)
-let platforms: [PackageDescription.SupportedPlatform]? = nil
-#endif
-
 let package = Package(
     name: "XMLCoder",
-    platforms: platforms,
+    platforms: [
+        .macOS(.v12),
+        .iOS(.v15),
+        .watchOS(.v8),
+        .tvOS(.v15)
+    ],
     products: [
         // Products define the executables and libraries produced by a package, and make them visible to other packages.
         .library(
             name: "XMLCoder",
             targets: ["XMLCoder"]
         ),
     ],
-    dependencies: [
-        // Dependencies declare other packages that this package depends on.
-        // .package(url: /* package url */, from: "1.0.0"),
-    ],
     targets: [
         // Targets are the basic building blocks of a package. A target can define a module or a test suite.
         // Targets can depend on other targets in this package, and on products in packages which this package depends on.
         .target(
-            name: "XMLCoder",
-            dependencies: []
+            name: "XMLCoder"
         ),
         .testTarget(
             name: "XMLCoderTests",

Sources/XMLCoder/Auxiliaries/Attribute.swift

@@ -40,6 +40,7 @@ extension Attribute: Codable where Value: Codable {
 
 extension Attribute: Equatable where Value: Equatable {}
 extension Attribute: Hashable where Value: Hashable {}
+extension Attribute: Sendable where Value: Sendable {}
 
 extension Attribute: ExpressibleByIntegerLiteral where Value: ExpressibleByIntegerLiteral {
     public typealias IntegerLiteralType = Value.IntegerLiteralType

Sources/XMLCoder/Auxiliaries/Box/DateBox.swift

@@ -43,14 +43,10 @@ struct DateBox: Equatable {
     }
 
     init?(iso8601 string: String) {
-        if #available(macOS 10.12, iOS 10.0, watchOS 3.0, tvOS 10.0, *) {
-            guard let unboxed = _iso8601Formatter.date(from: string) else {
-                return nil
-            }
-            self.init(unboxed, format: .iso8601)
-        } else {
-            fatalError("ISO8601DateFormatter is unavailable on this platform.")
+        guard let unboxed = try? Date(string, strategy: .iso8601) else {
+            return nil
         }
+        self.init(unboxed, format: .iso8601)
     }
 
     init?(xmlString: String, formatter: DateFormatter) {
@@ -69,11 +65,7 @@ struct DateBox: Equatable {
             let milliseconds = unboxed.timeIntervalSince1970 * 1000.0
             return milliseconds.description
         case .iso8601:
-            if #available(macOS 10.12, iOS 10.0, watchOS 3.0, tvOS 10.0, *) {
-                return _iso8601Formatter.string(from: self.unboxed)
-            } else {
-                fatalError("ISO8601DateFormatter is unavailable on this platform.")
-            }
+            return Date.ISO8601FormatStyle().format(self.unboxed)
         case let .formatter(formatter):
             return formatter.string(from: unboxed)
         }

Sources/XMLCoder/Auxiliaries/Element.swift

@@ -40,3 +40,4 @@ extension Element: Codable where Value: Codable {
 
 extension Element: Equatable where Value: Equatable {}
 extension Element: Hashable where Value: Hashable {}
+extension Element: Sendable where Value: Sendable {}

Sources/XMLCoder/Auxiliaries/ElementAndAttribute.swift

@@ -41,3 +41,4 @@ extension ElementAndAttribute: Codable where Value: Codable {
 
 extension ElementAndAttribute: Equatable where Value: Equatable {}
 extension ElementAndAttribute: Hashable where Value: Hashable {}
+extension ElementAndAttribute: Sendable where Value: Sendable {}

Sources/XMLCoder/Decoder/XMLDecoder.swift

@@ -26,7 +26,6 @@ open class XMLDecoder {
         case millisecondsSince1970
 
         /// Decode the `Date` as an ISO-8601-formatted string (in RFC 3339 format).
-        @available(macOS 10.12, iOS 10.0, watchOS 3.0, tvOS 10.0, *)
         case iso8601
 
         /// Decode the `Date` as a string parsed by the given formatter.

Sources/XMLCoder/Encoder/XMLEncoder.swift

@@ -13,7 +13,7 @@ open class XMLEncoder {
     // MARK: Options
 
     /// The formatting of the output XML data.
-    public struct OutputFormatting: OptionSet {
+    public struct OutputFormatting: OptionSet, Sendable {
         /// The format's default value.
         public let rawValue: UInt
 
@@ -39,7 +39,7 @@ open class XMLEncoder {
     }
 
     /// A node's encoding type. Specifies how a node will be encoded.
-    public enum NodeEncoding {
+    public enum NodeEncoding: Sendable {
         case attribute
         case element
         case both
@@ -59,7 +59,6 @@ open class XMLEncoder {
         case millisecondsSince1970
 
         /// Encode the `Date` as an ISO-8601-formatted string (in RFC 3339 format).
-        @available(macOS 10.12, iOS 10.0, watchOS 3.0, tvOS 10.0, *)
         case iso8601
 
         /// Encode the `Date` as a string formatted by the given formatter.
@@ -234,7 +233,7 @@ open class XMLEncoder {
     public typealias NodeEncodingStrategies = NodeEncodingStrategy
 
     public typealias XMLNodeEncoderClosure = (CodingKey) -> NodeEncoding?
-    public typealias XMLEncodingClosure = (Encodable.Type, Encoder) -> XMLNodeEncoderClosure
+    public typealias XMLEncodingClosure = @Sendable (Encodable.Type, Encoder) -> XMLNodeEncoderClosure
 
     /// Set of strategies to use for encoding of nodes.
     public enum NodeEncodingStrategy {

Tests/XMLCoderTests/AdvancedFeatures/PropertyWrappersTest.swift

@@ -9,7 +9,7 @@ import Foundation
 import XCTest
 import XMLCoder
 
-private struct Book: Codable, Equatable {
+private struct Book: Codable, Equatable, Sendable {
     @Attribute var id: Int
     @Element var name: String
     @ElementAndAttribute var authorID: Int

Tests/XMLCoderTests/CombineTests.swift

@@ -34,7 +34,6 @@ final class CustomEncoder: XMLEncoder {
     }
 }
 
-@available(iOS 13.0, macOS 10.15.0, tvOS 13.0, watchOS 6.0, *)
 final class CombineTests: XCTestCase {
     func testDecode() {
         var foo: Foo?