Emit destruction signal before child contexts are destroyed.

Verbatim comment from bug report:

When using a QtObject inside an item, and then we call a function
in the Component.onDestruction handler of that item, we get a
crash. This happens because the QDeclarativeContextData engine
has been invalidated before reaching
QDeclarativeExpressionPrivate::evalFunction.

Change code to emit the onDestruction signal before the child
contexts are invalidated.

Task-number: QTBUG-22535
Change-Id: Ic4983ae5fdf104ae977189c21dc202c9b02bc2bc
Reviewed-by: Chris Adams <christopher.adams@nokia.com>

1 files changed, 8 insertions, 8 deletions

diff --git a/src/declarative/qml/qdeclarativecontext.cpp b/src/declarative/qml/qdeclarativecontext.cpp
index 1723603d29..50e2235768 100644
--- a/src/declarative/qml/qdeclarativecontext.cpp
+++ b/src/declarative/qml/qdeclarativecontext.cpp
@@ -529,14 +529,6 @@ QDeclarativeContextData::QDeclarativeContextData(QDeclarativeContext *ctxt)
 
 void QDeclarativeContextData::invalidate()
 {
-    while (childContexts) {
-        if (childContexts->ownedByParent) {
-            childContexts->destroy();
-        } else {
-            childContexts->invalidate();
-        }
-    }
-
     while (componentAttached) {
         QDeclarativeComponentAttached *a = componentAttached;
         componentAttached = a->next;
@@ -548,6 +540,14 @@ void QDeclarativeContextData::invalidate()
         emit a->destruction();
     }
 
+    while (childContexts) {
+        if (childContexts->ownedByParent) {
+            childContexts->destroy();
+        } else {
+            childContexts->invalidate();
+        }
+    }
+
     if (prevChild) {
         *prevChild = nextChild;
         if (nextChild) nextChild->prevChild = prevChild;