From 55324650f9e759a43dce927f823c9858574106c3 Mon Sep 17 00:00:00 2001

From: Alexey Edelev <alexey.edelev@qt.io>

Date: Tue, 12 Jan 2021 16:37:09 +0100

Subject: [PATCH 36/36] Do not revert properties of deleted objects

If state contains revert action of properties of deleted objects,

we should avoid adding them to apply list

Fixes: QTBUG-85106

Pick-to: 5.15

Change-Id: Iff57eb9958a054476096f6d951ab7390277a2b39

Reviewed-by: Ulf Hermann <ulf.hermann@qt.io>

(cherry picked from commit 96763dbb105fde20431a264789ac27abfdab841c)

---

 src/quick/util/qquickstate.cpp                |  5 ++

 .../data/revertNullObjectBinding.qml          | 48 +++++++++++++

 .../quick/qquickstates/tst_qquickstates.cpp   | 68 +++++++++++++++++++

 3 files changed, 121 insertions(+)

 create mode 100644 tests/auto/quick/qquickstates/data/revertNullObjectBinding.qml

diff --git a/src/quick/util/qquickstate.cpp b/src/quick/util/qquickstate.cpp

index 71ab1f4d62..6a72754bde 100644

--- a/src/quick/util/qquickstate.cpp

+++ b/src/quick/util/qquickstate.cpp

@@ -635,6 +635,11 @@ void QQuickState::apply(QQuickTransition *trans, QQuickState *revert)

             }

         }

         if (!found) {

+            // If revert list contains bindings assigned to deleted objects, we need to

+            // prevent reverting properties of those objects.

+            if (d->revertList.at(ii).binding() && !d->revertList.at(ii).property().object()) {

+                continue;

+            }

             QVariant cur = d->revertList.at(ii).property().read();

             QQmlPropertyPrivate::removeBinding(d->revertList.at(ii).property());

diff --git a/tests/auto/quick/qquickstates/data/revertNullObjectBinding.qml b/tests/auto/quick/qquickstates/data/revertNullObjectBinding.qml

new file mode 100644

index 0000000000..dee82f52ed

--- /dev/null

+++ b/tests/auto/quick/qquickstates/data/revertNullObjectBinding.qml

@@ -0,0 +1,48 @@

+import QtQuick 2.12

+import Qt.test 1.0

+

+Item {

+    id: root

+    readonly property int someProp: 1234

+

+    property bool state1Active: false

+    property bool state2Active: false

+    StateGroup {

+        states: [

+            State {

+                id: state1

+                name: "state1"

+                when: state1Active

+                changes: [

+                    PropertyChanges {

+                        objectName: "propertyChanges1"

+                        target: ContainingObj.obj

+                        prop: root.someProp

+                    }

+                ]

+            }

+    ]}

+    StateGroup {

+        states: [

+            State {

+                id: state2

+                name: "state2"

+                when: state2Active

+                changes: [

+                    PropertyChanges {

+                        objectName: "propertyChanges2"

+                        target: ContainingObj.obj

+                        prop: 11111

+                    }

+                ]

+            }

+        ]

+    }

+

+    Component.onCompleted: {

+        state1Active = true;

+        state2Active = true;

+

+        ContainingObj.reset()

+    }

+}

diff --git a/tests/auto/quick/qquickstates/tst_qquickstates.cpp b/tests/auto/quick/qquickstates/tst_qquickstates.cpp

index d5fea3cb28..849522454f 100644

--- a/tests/auto/quick/qquickstates/tst_qquickstates.cpp

+++ b/tests/auto/quick/qquickstates/tst_qquickstates.cpp

@@ -79,6 +79,55 @@ private:

 QML_DECLARE_TYPE(MyRect)

 QML_DECLARE_TYPEINFO(MyRect, QML_HAS_ATTACHED_PROPERTIES)

+class RemovableObj : public QObject

+{

+    Q_OBJECT

+    Q_PROPERTY(int prop READ prop WRITE setProp NOTIFY propChanged)

+

+public:

+    RemovableObj(QObject *parent) : QObject(parent), m_prop(4321) { }

+    int prop() const { return m_prop; }

+

+public slots:

+    void setProp(int prop)

+    {

+        if (m_prop == prop)

+            return;

+

+        m_prop = prop;

+        emit propChanged(m_prop);

+    }

+

+signals:

+    void propChanged(int prop);

+

+private:

+    int m_prop;

+};

+

+class ContainingObj : public QObject

+{

+    Q_OBJECT

+    Q_PROPERTY(RemovableObj *obj READ obj NOTIFY objChanged)

+    RemovableObj *m_obj;

+

+public:

+    ContainingObj() : m_obj(new RemovableObj(this)) { }

+    RemovableObj *obj() const { return m_obj; }

+

+    Q_INVOKABLE void reset()

+    {

+        if (m_obj) {

+            m_obj->deleteLater();

+        }

+

+        m_obj = new RemovableObj(this);

+        emit objChanged();

+    }

+signals:

+    void objChanged();

+};

+

 class tst_qquickstates : public QQmlDataTest

 {

     Q_OBJECT

@@ -140,12 +189,20 @@ private slots:

     void duplicateStateName();

     void trivialWhen();

     void parentChangeCorrectReversal();

+    void revertNullObjectBinding();

 };

 void tst_qquickstates::initTestCase()

 {

     QQmlDataTest::initTestCase();

     qmlRegisterType<MyRect>("Qt.test", 1, 0, "MyRectangle");

+    qmlRegisterSingletonType<ContainingObj>(

+            "Qt.test", 1, 0, "ContainingObj", [](QQmlEngine *engine, QJSEngine *) {

+                static ContainingObj instance;

+                engine->setObjectOwnership(&instance, QQmlEngine::CppOwnership);

+                return &instance;

+            });

+    qmlRegisterUncreatableType<RemovableObj>("Qt.test", 1, 0, "RemovableObj", "Uncreatable");

 }

 QByteArray tst_qquickstates::fullDataPath(const QString &path) const

@@ -1692,6 +1749,17 @@ void tst_qquickstates::parentChangeCorrectReversal()

     QCOMPARE(oldX, stayingRectX.read().toDouble());

 }

+void tst_qquickstates::revertNullObjectBinding()

+{

+    QQmlEngine engine;

+

+    QQmlComponent c(&engine, testFileUrl("revertNullObjectBinding.qml"));

+    QScopedPointer<QObject> root { c.create() };

+    QVERIFY(root);

+    QTest::qWait(10);

+    QQmlProperty state2Active(root.get(), "state2Active");

+    state2Active.write(false);

+}

 QTEST_MAIN(tst_qquickstates)

-- 

2.31.1