From 5e0c3a798ab0d70be45a107661fc5f0a17322a2a Mon Sep 17 00:00:00 2001
From: Simon Hausmann <simon.hausmann@qt.io>
Date: Fri, 2 Mar 2018 09:09:17 +0100
Subject: Fix calling Qt.createComponent() from QQmlEngine::evaluate()

If we're run from a top-level evaluate() call from the JS engine, then
let's assume that any created components are top-level components that
belong to the root QML engine context. This is not quite a typical
use-case, but our API allows for this and this seems like an easy and
sensible solution.

Task-number: QTBUG-66792
Change-Id: Ic1c9171c257e8e60c0b2c43f9194bd038744ed2d
Reviewed-by: Oleg Yadrov <oleg.yadrov@qt.io>
Reviewed-by: Michael Brasser <michael.brasser@live.com>
---
 src/qml/qml/v8/qqmlbuiltinfunctions.cpp      | 10 ++++++++++
 tests/auto/qml/qqmlengine/tst_qqmlengine.cpp | 12 ++++++++++++
 2 files changed, 22 insertions(+)

diff --git a/src/qml/qml/v8/qqmlbuiltinfunctions.cpp b/src/qml/qml/v8/qqmlbuiltinfunctions.cpp
index c147feeb73..1371f1f041 100644
--- a/src/qml/qml/v8/qqmlbuiltinfunctions.cpp
+++ b/src/qml/qml/v8/qqmlbuiltinfunctions.cpp
@@ -1119,6 +1119,11 @@ ReturnedValue QtObject::method_createQmlObject(const FunctionObject *b, const Va
     QQmlEngine *engine = scope.engine->qmlEngine();
 
     QQmlContextData *context = scope.engine->callingQmlContext();
+    if (!context) {
+        QQmlEngine *qmlEngine = scope.engine->qmlEngine();
+        if (qmlEngine)
+            context = QQmlContextData::get(QQmlEnginePrivate::get(qmlEngine)->rootContext);
+    }
     Q_ASSERT(context);
     QQmlContext *effectiveContext = nullptr;
     if (context->isPragmaLibraryContext)
@@ -1246,6 +1251,11 @@ ReturnedValue QtObject::method_createComponent(const FunctionObject *b, const Va
     QQmlEngine *engine = scope.engine->qmlEngine();
 
     QQmlContextData *context = scope.engine->callingQmlContext();
+    if (!context) {
+        QQmlEngine *qmlEngine = scope.engine->qmlEngine();
+        if (qmlEngine)
+            context = QQmlContextData::get(QQmlEnginePrivate::get(qmlEngine)->rootContext);
+    }
     Q_ASSERT(context);
     QQmlContextData *effectiveContext = context;
     if (context->isPragmaLibraryContext)
diff --git a/tests/auto/qml/qqmlengine/tst_qqmlengine.cpp b/tests/auto/qml/qqmlengine/tst_qqmlengine.cpp
index bf964a5744..52e18011cb 100644
--- a/tests/auto/qml/qqmlengine/tst_qqmlengine.cpp
+++ b/tests/auto/qml/qqmlengine/tst_qqmlengine.cpp
@@ -76,6 +76,7 @@ private slots:
     void qmlContextProperties();
     void testGCCorruption();
     void testGroupedPropertyRevisions();
+    void componentFromEval();
 
 public slots:
     QObject *createAQObjectForOwnershipTest ()
@@ -885,6 +886,17 @@ void tst_qqmlengine::testGroupedPropertyRevisions()
     QVERIFY(!c2.errorString().isEmpty());
 }
 
+void tst_qqmlengine::componentFromEval()
+{
+    QQmlEngine engine;
+    const QUrl testUrl = testFileUrl("EmptyComponent.qml");
+    QJSValue result = engine.evaluate("Qt.createComponent(\"" + testUrl.toString() + "\");");
+    QPointer<QQmlComponent> component(qobject_cast<QQmlComponent*>(result.toQObject()));
+    QVERIFY(!component.isNull());
+    QScopedPointer<QObject> item(component->create());
+    QVERIFY(!item.isNull());
+}
+
 QTEST_MAIN(tst_qqmlengine)
 
 #include "tst_qqmlengine.moc"
-- 
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