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
Reviewed-by: Simon Hausmann <simon.hausmann@qt.io>
Change-Id: I255e18590d434e0487efac7c82c223752c645f25
(cherry-picked from commit 958e412a25523cc031564faae81c569aa6c3b01f)

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 d2934ba034..507f12cf3a 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 6d31ff9219..9d1aaa4458 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(
@@ -1329,6 +1330,29 @@ 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;