From 234dbbf25567ce44a8c8e099d003f04a12f2b371 Mon Sep 17 00:00:00 2001
From: Fabian Kosmale <fabian.kosmale@qt.io>
Date: Tue, 29 Oct 2019 16:11:21 +0100
Subject: QML Drag: Prevent crash when using image provider url

For attached property objects, qmlEngine will not return an engine.
However, QQuickDragAttached's parent is the object to which it is
attached, and from that one we can get the engine.

Fixes: QTBUG-72045
Change-Id: I40748dd11ea3eb4604c37e932b2cfd3baad6fd1f
Reviewed-by: Mitch Curtis <mitch.curtis@qt.io>
---
 src/quick/items/qquickdrag.cpp                 |  2 +-
 tests/auto/quick/qquickdrag/tst_qquickdrag.cpp | 25 +++++++++++++++++++++++++
 2 files changed, 26 insertions(+), 1 deletion(-)

diff --git a/src/quick/items/qquickdrag.cpp b/src/quick/items/qquickdrag.cpp
index a900406b17..a2cb739ff2 100644
--- a/src/quick/items/qquickdrag.cpp
+++ b/src/quick/items/qquickdrag.cpp
@@ -442,7 +442,7 @@ void QQuickDragAttached::setImageSource(const QUrl &url)
         if (url.isEmpty()) {
             d->pixmapLoader.clear();
         } else {
-            d->pixmapLoader.load(qmlEngine(this), url);
+            d->pixmapLoader.load(qmlEngine(parent()), url);
         }
 
         Q_EMIT imageSourceChanged();
diff --git a/tests/auto/quick/qquickdrag/tst_qquickdrag.cpp b/tests/auto/quick/qquickdrag/tst_qquickdrag.cpp
index 9d832066af..d3d3505e85 100644
--- a/tests/auto/quick/qquickdrag/tst_qquickdrag.cpp
+++ b/tests/auto/quick/qquickdrag/tst_qquickdrag.cpp
@@ -143,6 +143,7 @@ private slots:
     void source();
     void recursion_data();
     void recursion();
+    void noCrashWithImageProvider();
 
 private:
     QQmlEngine engine;
@@ -1279,6 +1280,30 @@ void tst_QQuickDrag::recursion()
     }
 }
 
+void tst_QQuickDrag::noCrashWithImageProvider()
+{
+    // QTBUG-72045
+    QQmlComponent component(&engine);
+    component.setData(
+    R"(
+    import QtQuick 2.9
+    Item {
+        Rectangle {
+            id: item
+            width: 50
+            height: 50
+            anchors.centerIn: parent
+            color: "orange"
+            Component.onCompleted: {
+                item.Drag.imageSource = "image://kill/me"
+            }
+        }
+    })", QUrl());
+    QScopedPointer<QObject> object(component.create());
+    QQuickItem *item = qobject_cast<QQuickItem *>(object.data());
+    QVERIFY(item);
+}
+
 
 QTEST_MAIN(tst_QQuickDrag)
 
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