4 files changed, 29 insertions, 1 deletions
diff --git a/src/declarative/qml/qdeclarativecomponent.cpp b/src/declarative/qml/qdeclarativecomponent.cpp
index d319e8f..5f26ad5 100644
--- a/src/declarative/qml/qdeclarativecomponent.cpp
+++ b/src/declarative/qml/qdeclarativecomponent.cpp
@@ -597,6 +597,11 @@ QDeclarativeComponentPrivate::beginCreate(QDeclarativeContextData *context, cons
         return 0;
     }
 
+    if (!context->isValid()) {
+        qWarning("QDeclarativeComponent::beginCreate(): Cannot create a component in an invalid context");
+        return 0;
+    }
+
     if (context->engine != engine) {
         qWarning("QDeclarativeComponent::beginCreate(): Must create component in context from the same QDeclarativeEngine");
         return 0;
diff --git a/src/declarative/qml/qdeclarativecontext.cpp b/src/declarative/qml/qdeclarativecontext.cpp
index 9307bcc..ba4da95 100644
--- a/src/declarative/qml/qdeclarativecontext.cpp
+++ b/src/declarative/qml/qdeclarativecontext.cpp
@@ -202,6 +202,12 @@ QDeclarativeContext::~QDeclarativeContext()
         d->data->destroy();
 }
 
+bool QDeclarativeContext::isValid() const
+{
+    Q_D(const QDeclarativeContext);
+    return d->data && d->data->isValid();
+}
+
 /*!
     Return the context's QDeclarativeEngine, or 0 if the context has no QDeclarativeEngine or the
     QDeclarativeEngine was destroyed.
@@ -245,6 +251,11 @@ void QDeclarativeContext::setContextObject(QObject *object)
         return;
     }
 
+    if (!isValid()) {
+        qWarning("QDeclarativeContext: Cannot set context object on invalid context.");
+        return;
+    }
+
     data->contextObject = object;
 }
 
@@ -264,6 +275,11 @@ void QDeclarativeContext::setContextProperty(const QString &name, const QVariant
         return;
     }
 
+    if (!isValid()) {
+        qWarning("QDeclarativeContext: Cannot set property on invalid context.");
+        return;
+    }
+
     if (data->engine) {
         bool ok;
         QObject *o = QDeclarativeEnginePrivate::get(data->engine)->toQObject(value, &ok);
@@ -305,6 +321,11 @@ void QDeclarativeContext::setContextProperty(const QString &name, QObject *value
         return;
     }
 
+    if (!isValid()) {
+        qWarning("QDeclarativeContext: Cannot set property on invalid context.");
+        return;
+    }
+
     if (!data->propertyNames) data->propertyNames = new QDeclarativeIntegerCache(data->engine);
     int idx = data->propertyNames->value(name);
 
diff --git a/src/declarative/qml/qdeclarativecontext.h b/src/declarative/qml/qdeclarativecontext.h
index 11b4771..94c9f4a 100644
--- a/src/declarative/qml/qdeclarativecontext.h
+++ b/src/declarative/qml/qdeclarativecontext.h
@@ -71,6 +71,8 @@ public:
     QDeclarativeContext(QDeclarativeContext *parent, QObject *objParent=0);
     virtual ~QDeclarativeContext();
 
+    bool isValid() const;
+
     QDeclarativeEngine *engine() const;
     QDeclarativeContext *parentContext() const;
 
diff --git a/src/declarative/qml/qdeclarativecontext_p.h b/src/declarative/qml/qdeclarativecontext_p.h
index 6059f72..7a16179 100644
--- a/src/declarative/qml/qdeclarativecontext_p.h
+++ b/src/declarative/qml/qdeclarativecontext_p.h
@@ -115,7 +115,7 @@ public:
     void destroy();
 
     inline bool isValid() const {
-        return engine && (!isInternal || contextObject && !QObjectPrivate::get(contextObject)->wasDeleted);
+        return engine && (!isInternal || !contextObject || !QObjectPrivate::get(contextObject)->wasDeleted);
     }
 
     // My parent context and engine