Fix default property preventing signals from being emitted.

Change the way connectAlias works so that even if the target
for the connection is not available immediately, anything that
is bound to it is notified when the target is changed.

(Fix is authored by Aaron).

Task-number: QTBUG-21580
Change-Id: Ida23c0e620069c50b123c71b5078929d4c7ec4e4
Reviewed-by: Martin Jones <martin.jones@nokia.com>

1 files changed, 34 insertions, 8 deletions

diff --git a/src/declarative/qml/qdeclarativecontext_p.h b/src/declarative/qml/qdeclarativecontext_p.h
index fb6473cb7a..92aa7bfafb 100644
--- a/src/declarative/qml/qdeclarativecontext_p.h
+++ b/src/declarative/qml/qdeclarativecontext_p.h
@@ -67,10 +67,12 @@
 #include <QtCore/qset.h>
 
 #include <private/qobject_p.h>
-#include "qdeclarativeguard_p.h"
+#include <private/qflagpointer_p.h>
+#include <private/qdeclarativeguard_p.h>
 
 #include <private/qv8_p.h>
 
+
 QT_BEGIN_NAMESPACE
 
 class QV8Bindings;
@@ -184,13 +186,13 @@ public:
     // id guards
     struct ContextGuard : public QDeclarativeGuard<QObject>
     {
-        ContextGuard() : context(0) {}
-        inline ContextGuard &operator=(QObject *obj)
-        { QDeclarativeGuard<QObject>::operator=(obj); return *this; }
-        virtual void objectDestroyed(QObject *) { 
-            if (context->contextObject && !QObjectPrivate::get(context->contextObject)->wasDeleted) bindings.notify(); 
-        }
-        QDeclarativeContextData *context;
+        inline ContextGuard();
+        inline ContextGuard &operator=(QObject *obj);
+        inline void objectDestroyed(QObject *);
+
+        inline bool wasSet() const;
+
+        QFlagPointer<QDeclarativeContextData> context;
         QDeclarativeNotifier bindings;
     };
     ContextGuard *idValues;
@@ -302,6 +304,30 @@ QDeclarativeGuardedContextData::operator=(QDeclarativeContextData *d)
     return *this;
 }
 
+QDeclarativeContextData::ContextGuard::ContextGuard()
+: context(0)
+{
+}
+
+QDeclarativeContextData::ContextGuard &QDeclarativeContextData::ContextGuard::operator=(QObject *obj)
+{
+    QDeclarativeGuard<QObject>::operator=(obj);
+    context.setFlag();
+    bindings.notify(); // For alias connections
+    return *this;
+}
+
+void QDeclarativeContextData::ContextGuard::objectDestroyed(QObject *)
+{
+    if (context->contextObject && !QObjectPrivate::get(context->contextObject)->wasDeleted)
+        bindings.notify();
+}
+
+bool QDeclarativeContextData::ContextGuard::wasSet() const
+{
+    return context.flag();
+}
+
 QT_END_NAMESPACE
 
 #endif // QDECLARATIVECONTEXT_P_H