QML debugger: Don't crash when creating objects on engine destruction

You can create further objects while the QML engine is being destroyed.
The debug service is not interested in those because they will be rather
short lived anyway.

Task-number: QTBUG-62458
Change-Id: If5395ef058268e0e956d159bc636495da1c0c98f
Reviewed-by: Simon Hausmann <simon.hausmann@qt.io>

2 files changed, 26 insertions, 1 deletions

diff --git a/src/plugins/qmltooling/qmldbg_debugger/qqmlenginedebugservice.cpp b/src/plugins/qmltooling/qmldbg_debugger/qqmlenginedebugservice.cpp
index 288ad243ce..236109d041 100644
--- a/src/plugins/qmltooling/qmldbg_debugger/qqmlenginedebugservice.cpp
+++ b/src/plugins/qmltooling/qmldbg_debugger/qqmlenginedebugservice.cpp
@@ -812,7 +812,8 @@ void QQmlEngineDebugServiceImpl::engineAboutToBeRemoved(QJSEngine *engine)
 void QQmlEngineDebugServiceImpl::objectCreated(QJSEngine *engine, QObject *object)
 {
     Q_ASSERT(engine);
-    Q_ASSERT(m_engines.contains(engine));
+    if (!m_engines.contains(engine))
+        return;
 
     int engineId = QQmlDebugService::idForObject(engine);
     int objectId = QQmlDebugService::idForObject(object);
diff --git a/tests/auto/qml/debugger/qqmlenginedebugservice/tst_qqmlenginedebugservice.cpp b/tests/auto/qml/debugger/qqmlenginedebugservice/tst_qqmlenginedebugservice.cpp
index d01d9a6791..89217e7556 100644
--- a/tests/auto/qml/debugger/qqmlenginedebugservice/tst_qqmlenginedebugservice.cpp
+++ b/tests/auto/qml/debugger/qqmlenginedebugservice/tst_qqmlenginedebugservice.cpp
@@ -141,6 +141,7 @@ private slots:
     void queryObjectWithNonStreamableTypes();
     void asynchronousCreate();
     void invalidContexts();
+    void createObjectOnDestruction();
 };
 
 QmlDebugObjectReference tst_QQmlEngineDebugService::findRootObject(
@@ -1345,6 +1346,29 @@ void tst_QQmlEngineDebugService::invalidContexts()
     QCOMPARE(m_dbg->rootContext().contexts.count(), 0);
 }
 
+void tst_QQmlEngineDebugService::createObjectOnDestruction()
+{
+    QSignalSpy spy(m_dbg, SIGNAL(newObject(int)));
+    {
+        QQmlEngine engine;
+        QQmlComponent component(&engine);
+        component.setData(
+                    "import QtQml 2.0;"
+                    "QtObject {"
+                        "property Component x:"
+                            "Qt.createQmlObject('import QtQml 2.0; Component { QtObject { } }',"
+                                                "this, 'x.qml');"
+                        "Component.onDestruction: x.createObject(this, {});"
+                    "}", QUrl::fromLocalFile("x.qml"));
+        QVERIFY(component.isReady());
+        QVERIFY(component.create());
+        QTRY_COMPARE(spy.count(), 2);
+    }
+    // Doesn't crash and doesn't give us another signal for the object created on destruction.
+    QTest::qWait(500);
+    QCOMPARE(spy.count(), 2);
+}
+
 int main(int argc, char *argv[])
 {
     int _argc = argc + 1;