QProperty: Refresh the observers after evaluating bindings

Evaluating bindings may actually break bindings, and remove observers.
Therefore, we need to re-fetch for notifying afterwards.

Fixes: QTBUG-94220
Change-Id: I96a78a825f983f58f1a574bf886e643f54453fdc
Reviewed-by: Fabian Kosmale <fabian.kosmale@qt.io>

1 files changed, 13 insertions, 8 deletions

diff --git a/src/corelib/kernel/qproperty.cpp b/src/corelib/kernel/qproperty.cpp
index 22e9e2d6e0..32c73278ec 100644
--- a/src/corelib/kernel/qproperty.cpp
+++ b/src/corelib/kernel/qproperty.cpp
@@ -546,16 +546,21 @@ void QPropertyBindingData::notifyObservers(QUntypedPropertyData *propertyDataPtr
     if (isNotificationDelayed())
         return;
     QPropertyBindingDataPointer d{this};
-    QPropertyObserverPointer observer = d.firstObserver();
-    if (!observer)
-        return;
-    auto *delay = groupUpdateData;
-    if (delay) {
-        delay->addProperty(this, propertyDataPtr);
+
+    if (QPropertyObserverPointer observer = d.firstObserver()) {
+        auto *delay = groupUpdateData;
+        if (delay) {
+            delay->addProperty(this, propertyDataPtr);
+            return;
+        }
+        observer.evaluateBindings();
+    } else {
         return;
     }
-    observer.evaluateBindings();
-    observer.notify(propertyDataPtr);
+
+    // evaluateBindings() can trash the observers. We need to re-fetch here.
+    if (QPropertyObserverPointer observer = d.firstObserver())
+        observer.notify(propertyDataPtr);
 }
 
 int QPropertyBindingDataPointer::observerCount() const