[utils] swift-xcodegen: Bump deployment target to macOS 15 and use Mutex

Author: AnthonyLatsis

utils/swift-xcodegen/Package.swift

@@ -6,7 +6,7 @@ import class Foundation.ProcessInfo
 
 let package = Package(
     name: "swift-xcodegen",
-    platforms: [.macOS(.v13)],
+    platforms: [.macOS(.v15)],
     targets: [
         .target(
             name: "SwiftXcodeGen",

utils/swift-xcodegen/Sources/SwiftXcodeGen/Concurrency/Lock.swift

@@ -0,0 +1,42 @@
+//===--- Mutex+Extensions.swift -------------------------------------------===//
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2025 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See https://swift.org/LICENSE.txt for license information
+// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
+//
+//===----------------------------------------------------------------------===//
+
+import Synchronization
+
+extension Mutex {
+  init() where Value == Void {
+    self.init(())
+  }
+
+  init<T>() where Value == T? {
+    self.init(nil)
+  }
+
+  init<T>() where Value == [T] {
+    self.init([])
+  }
+
+  init<T, U>() where Value == [T: U] {
+    self.init([:])
+  }
+}
+
+/// Having to write `_ in` when the value is `Void` is annoying.
+extension Mutex where Value == Void {
+  borrowing func withLock<Result: ~Copyable & Sendable, E>(
+    _ body: () throws(E) -> sending Result
+  ) throws(E) -> sending Result {
+    return try self.withLock { _ throws(E) in
+      try body()
+    }
+  }
+}

utils/swift-xcodegen/Sources/SwiftXcodeGen/Concurrency/Mutex+Extensions.swift

@@ -11,10 +11,11 @@
 //===----------------------------------------------------------------------===//
 
 import Foundation
+import Synchronization
 
 public final class Logger: @unchecked Sendable {
-  private let stateLock = Lock()
-  private let outputLock = Lock()
+  private let stateLock = Mutex<Void>()
+  private let outputLock = Mutex<Void>()
 
   private var _hadError = false
   public var hadError: Bool {
@@ -44,7 +45,7 @@ public final class Logger: @unchecked Sendable {
 }
 
 extension Logger {
-  public enum LogLevel: Comparable {
+  public enum LogLevel: Comparable, Sendable {
     /// A message with information that isn't useful to the user, but is
     /// useful when debugging issues.
     case debug

utils/swift-xcodegen/Sources/SwiftXcodeGen/Concurrency/MutexBox.swift

@@ -2,20 +2,22 @@
 //
 // This source file is part of the Swift.org open source project
 //
-// Copyright (c) 2024 Apple Inc. and the Swift project authors
+// Copyright (c) 2024 - 2025 Apple Inc. and the Swift project authors
 // Licensed under Apache License v2.0 with Runtime Library Exception
 //
 // See https://swift.org/LICENSE.txt for license information
 // See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
 //
 //===----------------------------------------------------------------------===//
 
+import Synchronization
+
 public final class NinjaBuildDir: Sendable {
   public let path: AbsolutePath
   public let projectRootDir: AbsolutePath
   private let _tripleSuffix: Result<String, Error>
 
-  private let repoBuildDirs = MutexBox<[Repo: RepoBuildDir]>()
+  private let repoBuildDirs = Mutex<[Repo: RepoBuildDir]>()
 
   private static func detectTripleSuffix(
     buildDir: AbsolutePath

utils/swift-xcodegen/Sources/SwiftXcodeGen/Logging/Logger.swift

@@ -2,14 +2,16 @@
 //
 // This source file is part of the Swift.org open source project
 //
-// Copyright (c) 2024 Apple Inc. and the Swift project authors
+// Copyright (c) 2024 - 2025 Apple Inc. and the Swift project authors
 // Licensed under Apache License v2.0 with Runtime Library Exception
 //
 // See https://swift.org/LICENSE.txt for license information
 // See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
 //
 //===----------------------------------------------------------------------===//
 
+import Synchronization
+
 public final class RepoBuildDir: Sendable {
   public let projectRootDir: AbsolutePath
   public let repo: Repo
@@ -19,10 +21,10 @@ public final class RepoBuildDir: Sendable {
 
   private let repoDirCache: DirectoryCache
 
-  private let _ninjaFile = MutexBox<NinjaBuildFile?>()
-  private let _runnableTargets = MutexBox<RunnableTargets?>()
-  private let _clangArgs = MutexBox<ClangBuildArgsProvider?>()
-  private let _swiftTargets = MutexBox<SwiftTargets?>()
+  private let _ninjaFile = Mutex<NinjaBuildFile?>()
+  private let _runnableTargets = Mutex<RunnableTargets?>()
+  private let _clangArgs = Mutex<ClangBuildArgsProvider?>()
+  private let _swiftTargets = Mutex<SwiftTargets?>()
 
   init(_ repo: Repo, for parent: NinjaBuildDir) throws {
     self.projectRootDir = parent.projectRootDir

utils/swift-xcodegen/Sources/SwiftXcodeGen/Ninja/NinjaBuildDir.swift

@@ -2,7 +2,7 @@
 //
 // This source file is part of the Swift.org open source project
 //
-// Copyright (c) 2024 Apple Inc. and the Swift project authors
+// Copyright (c) 2024 - 2025 Apple Inc. and the Swift project authors
 // Licensed under Apache License v2.0 with Runtime Library Exception
 //
 // See https://swift.org/LICENSE.txt for license information
@@ -11,13 +11,14 @@
 //===----------------------------------------------------------------------===//
 
 import Foundation
+import Synchronization
 
 /// A simple cache for the recursive contents of a directory under a given
 /// root path. This is pretty basic and doesn't handle cases where we've already
 /// cached the parent.
-struct DirectoryCache {
+struct DirectoryCache: ~Copyable {
   private let root: AbsolutePath
-  private let storage = MutexBox<[RelativePath: [RelativePath]]>()
+  private let storage = Mutex<[RelativePath: [RelativePath]]>()
 
   init(root: AbsolutePath) {
     self.root = root