asyncObserverQueue should be unique per NotificationCenter

Author: cthielen

Sources/FoundationEssentials/NotificationCenter/NotificationCenter.swift

@@ -76,6 +76,7 @@ private struct MessageBox {
 
 open class NotificationCenter: @unchecked Sendable {
     private var registrar: LockedState<[String? /* Notification name */: [ObjectIdentifier? /* object */ : AutoDictionary<@Sendable (MessageBox) -> Void>]]>
+    internal lazy var _actorQueueManager = _NotificationCenterActorQueueManager()
 
     public required init() {
         registrar = LockedState(initialState: [:])
@@ -149,6 +150,10 @@ open class NotificationCenter: @unchecked Sendable {
             _registrar.isEmpty
         }
     }
+    
+    internal func _getActorQueueManager() -> _NotificationCenterActorQueueManager {
+        return _actorQueueManager
+    }
 }
 
 extension NotificationCenter: Equatable {

Sources/FoundationEssentials/NotificationCenter/NotificationCenterMessage.swift

@@ -135,15 +135,7 @@ extension NotificationCenter {
 }
 
 extension NotificationCenter {
-#if FOUNDATION_FRAMEWORK
     internal var asyncObserverQueue: _NotificationCenterActorQueueManager {
         self._getActorQueueManager() as! _NotificationCenterActorQueueManager
     }
-#else
-    internal static let _actorQueueManager = _NotificationCenterActorQueueManager()
-
-    internal var asyncObserverQueue: _NotificationCenterActorQueueManager {
-        return Self._actorQueueManager
-    }
-#endif
 }

Tests/FoundationEssentialsTests/NotificationCenterTests.swift

@@ -7,9 +7,11 @@
 // See http://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
 //
 
-#if !FOUNDATION_FRAMEWORK
-
+#if FOUNDATION_FRAMEWORK
+@testable import Foundation
+#else
 @testable @_spi(SwiftCorelibsFoundation) import FoundationEssentials
+#endif
 
 import Testing
 
@@ -28,7 +30,8 @@ private struct NotificationCenterTests {
         let center2 = NotificationCenter()
         #expect(center1 != center2)
     }
-    
+
+#if !FOUNDATION_FRAMEWORK
     @Test func internalPostNotification() {
         nonisolated(unsafe) var flag = false
 
@@ -214,6 +217,13 @@ private struct NotificationCenterTests {
         center._removeObserver(observer2)
         center._removeObserver(observer3)
     }
-}
-
 #endif
+    
+    @MainActor
+    @Test func uniqueActorQueuePerCenter() {
+        let center1 = NotificationCenter()
+        let center2 = NotificationCenter()
+        
+        #expect(center1.asyncObserverQueue !== center2.asyncObserverQueue)
+    }
+}