Allow Locked to store non-Sendable elements (#9)

.github/workflows/ci.yml

@@ -1,12 +1,14 @@
+name: CI
+
 on: push
 
 jobs:
   test:
     runs-on: macos-12
 
     steps:
-      - uses: actions/checkout@v2
-      # Available environments: https://github.com/actions/virtual-environments/blob/main/images/macos/macos-12-Readme.md#xcode
-      - run: xcversion select 13.4
-      - run: swift package resolve
-      - run: swift test --skip-update
+      - uses: actions/checkout@v3
+      - name: Select Xcode 14
+        run: sudo xcode-select -s /Applications/Xcode_14.1.app
+      - name: Test
+        run: swift test

Sources/Synchronized/Locked.swift

@@ -1,6 +1,6 @@
 import Foundation
 
-public struct Locked<Element: Sendable>: @unchecked Sendable {
+public struct Locked<Element> {
     private final class Lock: ManagedBuffer<Element, os_unfair_lock> {
         deinit {
             withUnsafeMutablePointerToElements { lock in
@@ -13,7 +13,9 @@ public struct Locked<Element: Sendable>: @unchecked Sendable {
 
     public init(_ element: Element) {
         buffer = Lock.create(minimumCapacity: 1) { buffer in
-            buffer.withUnsafeMutablePointerToElements { $0.initialize(to: os_unfair_lock()) }
+            buffer.withUnsafeMutablePointerToElements {
+                $0.initialize(to: os_unfair_lock())
+            }
             return element
         }
     }
@@ -26,3 +28,5 @@ public struct Locked<Element: Sendable>: @unchecked Sendable {
         }
     }
 }
+
+extension Locked: @unchecked Sendable where Element: Sendable {}

Tests/SynchronizedTests/SynchronizedTests.swift

@@ -37,6 +37,17 @@ final class SynchronizedTests: XCTestCase {
         XCTAssertThrowsError(try lock.locked { throw TestError.locked })
     }
 
+    func testLockedElementDoesNotNeedToBeSendable() {
+        class ThreadUnsafe {
+            var name: String
+            init(name: String) { self.name = name }
+        }
+
+        let unsafe = Locked(ThreadUnsafe(name: "something"))
+        unsafe.access { $0.name = "else" }
+        XCTAssertEqual("else", unsafe.access { $0.name })
+    }
+
     func testCounterWithLock() {
         let iterations = 100_000
         let counter = Counter()

bin/format.sh

@@ -1,17 +1,25 @@
 #!/usr/bin/env bash
+# https://sharats.me/posts/shell-script-best-practices/
 
-set -e
+set -o errexit
+set -o nounset
+set -o pipefail
+if [[ "${TRACE-0}" == "1" ]]; then
+    set -o xtrace
+fi
 
-SELF=`realpath $0`
-DIR=`dirname $SELF`
-DEV_DIR=`echo ${DIR%/*}`
+if [[ "${1-}" =~ ^-*h(elp)?$ ]]; then
+    echo 'Usage: ./format.sh'
+    exit
+fi
 
-pushd "$DEV_DIR" &>/dev/null
+DIR=`dirname "$0"`
+pushd "$DIR/.." &>/dev/null
 
 if command -v swiftformat >/dev/null 2>&1; then
   swiftformat --quiet --config .swiftformat .
 else
-  echo "warning: Install swiftformat by running 'brew install swiftformat'"
+  echo "warning: Install swiftformat by running 'brew install swiftformat'" >&2
 fi
 
 popd &>/dev/null