Use QObjCWeakPointer to track QMacKeyValueObserver observed object

Otherwise we might run the risk that the observed object dies before
we try to do removeObserver.

Pick-to: 6.9
Change-Id: I2b54ff32728fc40fd47be2d14070fc43640f81bf
Reviewed-by: Volker Hilsheimer <[email protected]>
Reviewed-by: Thiago Macieira <[email protected]>

1 files changed, 2 insertions, 3 deletions

diff --git a/src/corelib/kernel/qcore_mac_p.h b/src/corelib/kernel/qcore_mac_p.h
index dc3f172937f..be839debd57 100644
--- a/src/corelib/kernel/qcore_mac_p.h
+++ b/src/corelib/kernel/qcore_mac_p.h
@@ -407,7 +407,6 @@ public:
     QMacKeyValueObserver() = default;
 
 #if defined( __OBJC__)
-    // Note: QMacKeyValueObserver must not outlive the object observed!
     QMacKeyValueObserver(NSObject *object, NSString *keyPath, Callback callback,
         NSKeyValueObservingOptions options = NSKeyValueObservingOptionNew)
         : object(object), keyPath(keyPath), callback(new Callback(callback))
@@ -435,7 +434,7 @@ public:
 
     void swap(QMacKeyValueObserver &other) noexcept
     {
-        qt_ptr_swap(object, other.object);
+        std::swap(object, other.object);
         qt_ptr_swap(keyPath, other.keyPath);
         callback.swap(other.callback);
     }
@@ -445,7 +444,7 @@ private:
     void addObserver(NSKeyValueObservingOptions options);
 #endif
 
-    NSObject *object = nullptr;
+    QObjCWeakPointer<NSObject> object;
     NSString *keyPath = nullptr;
     std::unique_ptr<Callback> callback;