Fix edge case in signal emission semantics

Signal emission triggered by property changes during an onDestruction
handler was previously not well tested.  This commit adds several
unit tests to ensure correct behaviour in that situation.

Those unit tests showed a problem in signal emission related to when
children objects are cleaned up.  This commit also ensures that if
such children own their own context, their onDestruction handlers
are called prior to marking the child as deleted.

Change-Id: Ibf84ae56ba1134e5d6402b742aee1bdc0e5e4e15
Reviewed-by: Matthew Vogt <matthew.vogt@nokia.com>

2 files changed, 15 insertions, 12 deletions

diff --git a/src/qml/qml/qqmldata_p.h b/src/qml/qml/qqmldata_p.h
index 2c2c597de4..12344e3a6b 100644
--- a/src/qml/qml/qqmldata_p.h
+++ b/src/qml/qml/qqmldata_p.h
@@ -193,7 +193,7 @@ public:
     static inline bool wasDeleted(QObject *);
 
     static void markAsDeleted(QObject *);
-    static inline void setQueuedForDeletion(QObject *);
+    static void setQueuedForDeletion(QObject *);
 
 private:
     // For attachedProperties
@@ -213,17 +213,6 @@ bool QQmlData::wasDeleted(QObject *object)
            static_cast<QQmlData *>(priv->declarativeData)->isQueuedForDeletion;
 }
 
-void QQmlData::setQueuedForDeletion(QObject *object)
-{
-    if (object) {
-        if (QObjectPrivate *priv = QObjectPrivate::get(object)) {
-            if (!priv->wasDeleted && priv->declarativeData) {
-                static_cast<QQmlData *>(priv->declarativeData)->isQueuedForDeletion = true;
-            }
-        }
-    }
-}
-
 QQmlNotifierEndpoint *QQmlData::notify(int index)
 {
     Q_ASSERT(index <= 0xFFFF);
diff --git a/src/qml/qml/qqmlengine.cpp b/src/qml/qml/qqmlengine.cpp
index 22d2845f61..7eed2f9e08 100644
--- a/src/qml/qml/qqmlengine.cpp
+++ b/src/qml/qml/qqmlengine.cpp
@@ -477,6 +477,20 @@ void QQmlData::markAsDeleted(QObject *o)
     }
 }
 
+void QQmlData::setQueuedForDeletion(QObject *object)
+{
+    if (object) {
+        if (QObjectPrivate *priv = QObjectPrivate::get(object)) {
+            if (!priv->wasDeleted && priv->declarativeData) {
+                QQmlData *ddata = QQmlData::get(object, false);
+                if (ddata->ownContext && ddata->context)
+                    ddata->context->emitDestruction();
+                ddata->isQueuedForDeletion = true;
+            }
+        }
+    }
+}
+
 void QQmlEnginePrivate::init()
 {
     Q_Q(QQmlEngine);