1 files changed, 51 insertions, 8 deletions

diff --git a/tests/auto/qml/qqmlenginecleanup/tst_qqmlenginecleanup.cpp b/tests/auto/qml/qqmlenginecleanup/tst_qqmlenginecleanup.cpp
index d0a8b6401f..7e9a1524b0 100644
--- a/tests/auto/qml/qqmlenginecleanup/tst_qqmlenginecleanup.cpp
+++ b/tests/auto/qml/qqmlenginecleanup/tst_qqmlenginecleanup.cpp
@@ -31,6 +31,8 @@
 #include <QtQml/qqml.h>
 #include <QtQml/QQmlEngine>
 #include <QtQml/QQmlComponent>
+#include <private/qhashedstring_p.h>
+#include <private/qqmlmetatype_p.h>
 
 //Separate test, because if engine cleanup attempts fail they can easily break unrelated tests
 class tst_qqmlenginecleanup : public QQmlDataTest
@@ -44,41 +46,82 @@ private slots:
     void test_valueTypeProviderModule(); // QTBUG-43004
 };
 
+// A wrapper around QQmlComponent to ensure the temporary reference counts
+// on the type data as a result of the main thread <> loader thread communication
+// are dropped. Regular Synchronous loading will leave us with an event posted
+// to the gui thread and an extra refcount that will only be dropped after the
+// event delivery. A plain sendPostedEvents() however is insufficient because
+// we can't be sure that the event is posted after the constructor finished.
+class CleanlyLoadingComponent : public QQmlComponent
+{
+public:
+    CleanlyLoadingComponent(QQmlEngine *engine, const QUrl &url)
+        : QQmlComponent(engine, url, QQmlComponent::Asynchronous)
+    { waitForLoad(); }
+    CleanlyLoadingComponent(QQmlEngine *engine, const QString &fileName)
+        : QQmlComponent(engine, fileName, QQmlComponent::Asynchronous)
+    { waitForLoad(); }
+
+    void waitForLoad()
+    {
+        QTRY_VERIFY(status() == QQmlComponent::Ready || status() == QQmlComponent::Error);
+    }
+};
+
 void tst_qqmlenginecleanup::test_qmlClearTypeRegistrations()
 {
     //Test for preventing memory leaks is in tests/manual/qmltypememory
     QQmlEngine* engine;
-    QQmlComponent* component;
+    CleanlyLoadingComponent* component;
     QUrl testFile = testFileUrl("types.qml");
 
+    const auto qmlTypeForTestType = []() {
+        return QQmlMetaType::qmlType(QStringLiteral("TestTypeCpp"), QStringLiteral("Test"), 2, 0);
+    };
+
+    QVERIFY(!qmlTypeForTestType().isValid());
     qmlRegisterType<QObject>("Test", 2, 0, "TestTypeCpp");
+    QVERIFY(qmlTypeForTestType().isValid());
+
     engine = new QQmlEngine;
-    component = new QQmlComponent(engine, testFile);
+    component = new CleanlyLoadingComponent(engine, testFile);
     QVERIFY(component->isReady());
 
-    delete engine;
     delete component;
-    qmlClearTypeRegistrations();
+    delete engine;
+
+    {
+        auto cppType = qmlTypeForTestType();
+
+        qmlClearTypeRegistrations();
+        QVERIFY(!qmlTypeForTestType().isValid());
+
+        // cppType should hold the last ref, qmlClearTypeRegistration should have wiped
+        // all internal references.
+        QCOMPARE(QQmlType::refCount(cppType.priv()), 1);
+    }
 
     //2nd run verifies that types can reload after a qmlClearTypeRegistrations
     qmlRegisterType<QObject>("Test", 2, 0, "TestTypeCpp");
+    QVERIFY(qmlTypeForTestType().isValid());
     engine = new QQmlEngine;
-    component = new QQmlComponent(engine, testFile);
+    component = new CleanlyLoadingComponent(engine, testFile);
     QVERIFY(component->isReady());
 
-    delete engine;
     delete component;
+    delete engine;
     qmlClearTypeRegistrations();
+    QVERIFY(!qmlTypeForTestType().isValid());
 
     //3nd run verifies that TestTypeCpp is no longer registered
     engine = new QQmlEngine;
-    component = new QQmlComponent(engine, testFile);
+    component = new CleanlyLoadingComponent(engine, testFile);
     QVERIFY(component->isError());
     QCOMPARE(component->errorString(),
             testFile.toString() +":33 module \"Test\" is not installed\n");
 
-    delete engine;
     delete component;
+    delete engine;
 }
 
 static void cleanState(QQmlEngine **e)