Refactor Cache locking mechanism to use NSRecursiveLock for improved thread safety and prevent deadlocks. Added comprehensive thread safety tests to validate the fix and ensure no new locking issues are introduced. (#22)

* Refactor Cache locking mechanism to use NSRecursiveLock for improved thread safety and prevent deadlocks. Added comprehensive thread safety tests to validate the fix and ensure no new locking issues are introduced.

* Refactor ThreadSafetyTests to improve clarity and maintain compatibility with Windows. Added type annotations for ComposableCache and AnyCacheable instances, and wrapped tests in conditional compilation to exclude them on Windows.

* Add cache initialization in thread safety tests to avoid redundant instantiation. This change enhances test clarity and performance by reusing the cache instance across multiple operations.

* Enhance thread safety tests by refining cache initialization and improving test clarity. Updated comments to reflect changes in locking mechanisms and added new test scenarios to validate cache behavior under high contention and mixed operations.

Author: 0xLeif

Sources/Cache/Cache/Cache.swift

@@ -16,7 +16,8 @@ import Foundation
 open class Cache<Key: Hashable, Value>: Cacheable, @unchecked Sendable {
 
     /// Lock to synchronize the access to the cache dictionary.
-    fileprivate var lock: NSLock
+    /// Using NSRecursiveLock to prevent re-entrant lock deadlocks with @Published property wrapper
+    fileprivate var lock: NSRecursiveLock
 
     #if os(Linux) || os(Windows)
     fileprivate var cache: [Key: Value] = [:]
@@ -31,7 +32,7 @@ open class Cache<Key: Hashable, Value>: Cacheable, @unchecked Sendable {
      - Parameter initialValues: An optional dictionary of initial key-value pairs.
      */
     required public init(initialValues: [Key: Value] = [:]) {
-        lock = NSLock()
+        lock = NSRecursiveLock()
         cache = initialValues
     }