ref: Swift NSLock return value (#3741)

Use generics to allow a return value for NSLock synchronized.

Author: philipphofmann

Sources/Swift/Extensions/NSLock.swift

@@ -5,9 +5,11 @@ extension NSLock {
     /// Executes the closure while acquiring the lock.
     ///
     /// - Parameter closure: The closure to run.
-    func synchronized(_ closure: () throws -> Void) rethrows {
-        self.lock()
+    ///
+    /// - Returns:           The value the closure generated.
+    func synchronized<T>(_ closure: () throws -> T) rethrows -> T {
         defer { self.unlock() }
-        try closure()
+        self.lock()
+        return try closure()
     }
 }

Tests/SentryTests/Swift/Extensions/NSLockTests.swift

@@ -10,12 +10,18 @@ final class NSLockTests: XCTestCase {
         var value = 0
 
         testConcurrentModifications(asyncWorkItems: 10, writeLoopCount: 9, writeWork: { _ in
+            let returnValue: Int = lock.synchronized {
+                value += 1
+                return 10
+            }
+            expect(returnValue) == 10
+            
             lock.synchronized {
                 value += 1
             }
         })
 
-        expect(value) == 100
+        expect(value) == 200
     }
 
     func testUnlockWhenThrowing() throws {