Check that animation still exists

Fixes: QTBUG-76749
Change-Id: Ie5eed240e8190a7297f71f5e40870a007e737d1d
Reviewed-by: Simon Hausmann <simon.hausmann@qt.io>
Reviewed-by: Mitch Curtis <mitch.curtis@qt.io>

src/quick/util/qquickbehavior.cpp

@@ -143,7 +143,7 @@ void QQuickBehavior::setAnimation(QQuickAbstractAnimation *animation)
 
 void QQuickBehaviorPrivate::animationStateChanged(QAbstractAnimationJob *, QAbstractAnimationJob::State newState,QAbstractAnimationJob::State)
 {
-    if (!blockRunningChanged)
+    if (!blockRunningChanged && animation)
         animation->notifyRunningChanged(newState == QAbstractAnimationJob::Running);
 }
 

tests/auto/quick/qquickbehaviors/data/delete.qml

@@ -0,0 +1,37 @@
+import QtQuick 2.12
+
+Item {
+    visible: true
+    width: 640
+    height: 480
+
+    Component.onCompleted: {
+            myLoader.active = false
+    }
+
+    Loader {
+        id: myLoader
+
+        active: true
+        sourceComponent: Item {
+            width: 100
+            height: 100
+            id: myPopup
+
+            NumberAnimation {
+                id: anim
+            }
+
+            Rectangle {
+                color: "black"
+                Component.onCompleted: {
+                    opacity = 20
+                }
+
+                Behavior on opacity {
+                    animation: anim
+                }
+            }
+        }
+    }
+}

tests/auto/quick/qquickbehaviors/tst_qquickbehaviors.cpp

@@ -74,6 +74,7 @@ private slots:
     void aliasedProperty();
     void innerBehaviorOverwritten();
     void oneWay();
+    void safeToDelete();
 };
 
 void tst_qquickbehaviors::simpleBehavior()
@@ -647,6 +648,16 @@ void tst_qquickbehaviors::oneWay()
     QCOMPARE(myAnimation->isRunning(), false);
 }
 
+// QTBUG-76749
+void tst_qquickbehaviors::safeToDelete()
+{
+    QQmlEngine engine;
+    QQmlComponent c(&engine, testFileUrl("delete.qml"));
+    QVERIFY(c.create());
+}
+
+
+
 QTEST_MAIN(tst_qquickbehaviors)
 
 #include "tst_qquickbehaviors.moc"