Add support for Swift 6

.circleci/config.pkl

@@ -125,7 +125,7 @@ jobs {
     ["test-pkl-\(distribution.normalizedVersion)"] {
       docker {
         new {
-          image = "swift:5.10-rhel-ubi9"
+          image = "swift:6.1-rhel-ubi9"
         }
       }
       resource_class = "xlarge"
@@ -163,7 +163,7 @@ jobs {
   ["test-format"] {
     docker {
       new {
-        image = "swift:5.10-rhel-ubi9"
+        image = "swift:6.1-rhel-ubi9"
       }
     }
     steps {
@@ -197,7 +197,7 @@ jobs {
     ["pkl-gen-swift-linux-\(arch)"] {
       docker {
         new {
-          image = "swift:5.10-rhel-ubi9"
+          image = "swift:6.1-rhel-ubi9"
         }
       }
       resource_class = if (arch == "amd64") "xlarge" else "arm.xlarge"

.circleci/config.yml

@@ -24,7 +24,7 @@ jobs:
         path: .out/test-results/
     resource_class: xlarge
     docker:
-    - image: swift:5.10-rhel-ubi9
+    - image: swift:6.1-rhel-ubi9
   test-pkl-0-29-0:
     steps:
     - checkout
@@ -52,7 +52,7 @@ jobs:
         path: .out/test-results/
     resource_class: xlarge
     docker:
-    - image: swift:5.10-rhel-ubi9
+    - image: swift:6.1-rhel-ubi9
   test-license-headers:
     steps:
     - checkout
@@ -66,7 +66,7 @@ jobs:
     - run:
         command: make swiftformat-lint
     docker:
-    - image: swift:5.10-rhel-ubi9
+    - image: swift:6.1-rhel-ubi9
   pkl-gen-swift-macos:
     steps:
     - checkout
@@ -98,7 +98,7 @@ jobs:
         - out/
     resource_class: arm.xlarge
     docker:
-    - image: swift:5.10-rhel-ubi9
+    - image: swift:6.1-rhel-ubi9
   pkl-gen-swift-linux-amd64:
     steps:
     - checkout
@@ -114,7 +114,7 @@ jobs:
         - out/
     resource_class: xlarge
     docker:
-    - image: swift:5.10-rhel-ubi9
+    - image: swift:6.1-rhel-ubi9
   pkl-package:
     steps:
     - checkout

DEVELOPMENT.adoc

@@ -28,4 +28,6 @@ make format
 swiftformat .
 
 hawkeye format
-----
+----
+
+To regenerate all the test fixtures after changes to the codegen run `make generate-fixtures`.

Package.swift

@@ -1,4 +1,4 @@
-// swift-tools-version: 5.10
+// swift-tools-version: 6.0
 //===----------------------------------------------------------------------===//
 // Copyright © 2024-2025 Apple Inc. and the Pkl project authors. All rights reserved.
 //
@@ -49,28 +49,33 @@ let package = Package(
     targets: [
         .target(
             name: "PklSwift",
-            dependencies: ["MessagePack", "PklSwiftInternals", "SemanticVersion"]
+            dependencies: ["MessagePack", "PklSwiftInternals", "SemanticVersion"],
+            swiftSettings: [.enableUpcomingFeature("StrictConcurrency")]
         ),
         .target(
-            name: "PklSwiftInternals"
+            name: "PklSwiftInternals",
+            swiftSettings: [.enableUpcomingFeature("StrictConcurrency")]
         ),
         .target(
             name: "MessagePack",
             dependencies: [
                 .product(name: "SystemPackage", package: "swift-system"),
-            ]
+            ],
+            swiftSettings: [.enableUpcomingFeature("StrictConcurrency")]
         ),
         .executableTarget(
             name: "pkl-gen-swift",
             dependencies: [
                 .product(name: "ArgumentParser", package: "swift-argument-parser"),
                 "PklSwift",
             ],
-            resources: [.embedInCode("Resources/VERSION.txt")]
+            resources: [.embedInCode("Resources/VERSION.txt")],
+            swiftSettings: [.enableUpcomingFeature("StrictConcurrency")]
         ),
         .executableTarget(
             name: "test-external-reader",
-            dependencies: ["PklSwift"]
+            dependencies: ["PklSwift"],
+            swiftSettings: [.enableUpcomingFeature("StrictConcurrency")]
         ),
         .testTarget(
             name: "PklSwiftTests",
@@ -87,14 +92,17 @@ let package = Package(
                 "Fixtures/Collections.pkl",
                 "Fixtures/Poly.pkl",
                 "Fixtures/ApiTypes.pkl",
-            ]
+            ],
+            swiftSettings: [.enableUpcomingFeature("StrictConcurrency")]
         ),
         .testTarget(
             name: "MessagePackTests",
             dependencies: [
                 "MessagePack",
-            ]
+            ],
+            swiftSettings: [.enableUpcomingFeature("StrictConcurrency")]
         ),
     ],
+    swiftLanguageModes: [.v5, .v6],
     cxxLanguageStandard: .cxx20
 )

Sources/MessagePack/Decoder/MessagePackDecoder.swift

@@ -417,7 +417,7 @@ public final class MessagePackDecoder {
 }
 
 /// A generic representation of MessagePack values.
-public enum MessagePackValue {
+public enum MessagePackValue: @unchecked Sendable {
     case `nil`
     case bool(Bool)
     case int(any BinaryInteger)

Sources/MessagePack/Decoder/SingleValueDecodingContainer.swift

@@ -92,7 +92,7 @@ extension _MessagePackDecoder.SingleValueContainer: SingleValueDecodingContainer
         }
     }
 
-    func decode(_: Date.Type) throws -> Date {
+    private func decode(_: Date.Type) throws -> Date {
         switch value {
         case .timestamp(let value):
             return value
@@ -101,7 +101,7 @@ extension _MessagePackDecoder.SingleValueContainer: SingleValueDecodingContainer
         }
     }
 
-    func decode(_: Data.Type) throws -> Data {
+    private func decode(_: Data.Type) throws -> Data {
         switch value {
         case .bin(let value):
             return Data(value)
@@ -110,7 +110,7 @@ extension _MessagePackDecoder.SingleValueContainer: SingleValueDecodingContainer
         }
     }
 
-    func decode(_: [UInt8].Type) throws -> [UInt8] {
+    private func decode(_: [UInt8].Type) throws -> [UInt8] {
         // accept either msgpack binary or array
         switch value {
         case .bin(let value):
@@ -130,7 +130,7 @@ extension _MessagePackDecoder.SingleValueContainer: SingleValueDecodingContainer
         }
     }
 
-    func decode(_: URL.Type) throws -> URL {
+    private func decode(_: URL.Type) throws -> URL {
         switch value {
         case .string(let value):
             if let url = URL(string: value) {

Sources/MessagePack/Encoder/SingleValueEncodingContainer.swift

@@ -219,7 +219,7 @@ extension _MessagePackEncoder.SingleValueContainer: SingleValueEncodingContainer
         self.storage.append(contentsOf: value.bytes)
     }
 
-    func encode(_ value: Date) throws {
+    private func encode(_ value: Date) throws {
         try checkCanEncode(value: value)
         defer { self.canEncodeNewValue = false }
 
@@ -246,7 +246,7 @@ extension _MessagePackEncoder.SingleValueContainer: SingleValueEncodingContainer
         }
     }
 
-    func encode(_ value: Data) throws {
+    private func encode(_ value: Data) throws {
         let length = value.count
         if let uint8 = UInt8(exactly: length) {
             self.storage.append(0xC4)
@@ -269,7 +269,7 @@ extension _MessagePackEncoder.SingleValueContainer: SingleValueEncodingContainer
         }
     }
 
-    func encode(_ value: [UInt8]) throws {
+    private func encode(_ value: [UInt8]) throws {
         let length = value.count
         if let uint8 = UInt8(exactly: length) {
             self.storage.append(0xC4)
@@ -292,7 +292,7 @@ extension _MessagePackEncoder.SingleValueContainer: SingleValueEncodingContainer
         }
     }
 
-    func encode(_ value: URL) throws {
+    private func encode(_ value: URL) throws {
         try self.encode(value.absoluteString)
     }
 

Sources/MessagePack/IO.swift

@@ -14,7 +14,7 @@
 // limitations under the License.
 //===----------------------------------------------------------------------===//
 
-public protocol Writer {
+public protocol Writer: Sendable {
     /// Write the given bytes into an output somewhere.
     func write(_ buffer: UnsafeRawBufferPointer) throws
 
@@ -32,7 +32,7 @@ extension Writer {
     }
 }
 
-public protocol Reader {
+public protocol Reader: Sendable {
     /// Reads bytes from somewhere, writing them into the given bytearray.
     func read(into: UnsafeMutableRawBufferPointer) throws -> Int
 
@@ -41,7 +41,7 @@ public protocol Reader {
 }
 
 /// Writes bytes into an internal buffer.
-public class BufferWriter: Writer {
+public class BufferWriter: Writer, @unchecked Sendable {
     var bytes: [UInt8] = []
 
     public func write(_ buffer: UnsafeRawBufferPointer) throws {
@@ -54,7 +54,7 @@ public class BufferWriter: Writer {
 }
 
 /// Reads bytes from the provided buffer.
-public class BufferReader: Reader {
+public class BufferReader: Reader, @unchecked Sendable {
     let bytes: [UInt8]
     var index: Int
 
@@ -81,7 +81,7 @@ public class BufferReader: Reader {
 }
 
 /// Like [Reader], but also supports a way to peek bytes.
-class PeekableReader: Reader {
+class PeekableReader: Reader, @unchecked Sendable {
     var peekedByte: UInt8?
 
     let reader: Reader

Sources/PklSwift/API/DataSize.swift

@@ -18,7 +18,7 @@ import Foundation
 import MessagePack
 
 /// DataSize is the Swift representation of Pkl's `pkl.DataSize`.
-public struct DataSize: Hashable {
+public struct DataSize: Hashable, Sendable {
     /// The value of this ``DataSize`` in the unit set in ``unit``.
     let value: Float64
 
@@ -150,7 +150,7 @@ extension DataSize {
 }
 
 /// The unit of a ``DataSize``.
-public enum DataSizeUnit: String, CaseIterable, Decodable {
+public enum DataSizeUnit: String, CaseIterable, Decodable, Sendable {
     /// byte
     case b
 

Sources/PklSwift/API/Duration.swift

@@ -17,7 +17,7 @@
 import Foundation
 
 /// Duration is the Swift representation of Pkl's `pkl.Duration`.
-public struct Duration: Hashable {
+public struct Duration: Hashable, Sendable {
     /// The value of this ``Duration`` in the unit set in ``unit``.
     public let value: Float64
 
@@ -137,7 +137,7 @@ extension Duration {
 }
 
 /// A unit (magnitude) of duration.
-public enum DurationUnit: String, CaseIterable, Decodable {
+public enum DurationUnit: String, CaseIterable, Decodable, Sendable {
     /// Nanosecond
     case ns
 

Sources/PklSwift/Decoder/PklDecoder.swift

@@ -17,7 +17,7 @@
 import Foundation
 import MessagePack
 
-public enum PklValueType: UInt8, Decodable {
+public enum PklValueType: UInt8, Decodable, Sendable {
     case object = 0x1
     case map = 0x2
     case mapping = 0x3

Sources/PklSwift/Evaluator.swift

@@ -22,7 +22,7 @@ import Foundation
 /// - Parameters:
 ///   - options: The options used to configure the evaluator.
 ///   - action: The action to perform.
-public func withEvaluator<T>(options: EvaluatorOptions, _ action: (Evaluator) async throws -> T) async throws -> T {
+public func withEvaluator<T: Sendable>(options: EvaluatorOptions, _ action: (Evaluator) async throws -> T) async throws -> T {
     try await withEvaluatorManager { manager in
         let evaluator: Evaluator = try await manager.newEvaluator(options: options)
         return try await action(evaluator)
@@ -32,7 +32,7 @@ public func withEvaluator<T>(options: EvaluatorOptions, _ action: (Evaluator) as
 /// Like ``withEvaluator(options:_:)``, but with preconfigured evaluator options.
 ///
 /// - Parameter action: The action to perform
-public func withEvaluator<T>(_ action: (Evaluator) async throws -> T) async throws -> T {
+public func withEvaluator<T: Sendable>(_ action: (Evaluator) async throws -> T) async throws -> T {
     try await withEvaluator(options: .preconfigured, action)
 }
 
@@ -42,7 +42,7 @@ public func withEvaluator<T>(_ action: (Evaluator) async throws -> T) async thro
 ///   - projectBaseURI: The base path containing the PklProject file.
 ///   - action: The action to perform.
 /// - Returns: The result of the action.
-public func withProjectEvaluator<T>(projectBaseURI: URL, _ action: (Evaluator) async throws -> T) async throws -> T {
+public func withProjectEvaluator<T: Sendable>(projectBaseURI: URL, _ action: (Evaluator) async throws -> T) async throws -> T {
     try await withProjectEvaluator(projectBaseURI: projectBaseURI, options: .preconfigured, action)
 }
 
@@ -57,7 +57,7 @@ public func withProjectEvaluator<T>(projectBaseURI: URL, _ action: (Evaluator) a
 ///   - options: The base options used to configure the evaluator.
 ///   - action: The action to perform.
 /// - Returns: The result of the action.
-public func withProjectEvaluator<T>(
+public func withProjectEvaluator<T: Sendable>(
     projectBaseURI: URL,
     options: EvaluatorOptions,
     _ action: (Evaluator) async throws -> T
@@ -69,7 +69,7 @@ public func withProjectEvaluator<T>(
 }
 
 /// The core API for evaluating Pkl modules.
-public struct Evaluator {
+public struct Evaluator: Sendable {
     private var manager: EvaluatorManager
     private let evaluatorID: Int64
     private let resourceReaders: [ResourceReader]