Restore value bindings when disabling a Binding element

We previously only restored script bindings that were replaced by
a Binding. Now we handle both.

[ChangeLog] QML Binding elements now support restoring previous values
of the bound property when the binding is disabled. This will be the
default behavior in Qt 5.15. Reliance on the old behavior of only
restoring binding, not literal values results in a warning now.

Fixes: QTBUG-33444
Change-Id: I833403b0645c08eee486fbd4acf5d3c7de2ef73a
Reviewed-by: Michael Brasser <michael.brasser@live.com>

1 files changed, 75 insertions, 0 deletions

diff --git a/tests/auto/qml/qqmlbinding/tst_qqmlbinding.cpp b/tests/auto/qml/qqmlbinding/tst_qqmlbinding.cpp
index 34cf21024d..717fd5dbd1 100644
--- a/tests/auto/qml/qqmlbinding/tst_qqmlbinding.cpp
+++ b/tests/auto/qml/qqmlbinding/tst_qqmlbinding.cpp
@@ -42,6 +42,9 @@ private slots:
     void binding();
     void whenAfterValue();
     void restoreBinding();
+    void restoreBindingValue();
+    void restoreBindingVarValue();
+    void restoreBindingJSValue();
     void restoreBindingWithLoop();
     void restoreBindingWithoutCrash();
     void deletedObject();
@@ -134,6 +137,78 @@ void tst_qqmlbinding::restoreBinding()
     delete rect;
 }
 
+void tst_qqmlbinding::restoreBindingValue()
+{
+    QQmlEngine engine;
+    QQmlComponent c(&engine, testFileUrl("restoreBinding2.qml"));
+    QScopedPointer<QQuickRectangle> rect(qobject_cast<QQuickRectangle*>(c.create()));
+    QVERIFY(!rect.isNull());
+
+    auto myItem = qobject_cast<QQuickRectangle*>(rect->findChild<QQuickRectangle*>("myItem"));
+    QVERIFY(myItem != nullptr);
+
+    QCOMPARE(myItem->height(), 100);
+    myItem->setProperty("when", QVariant(false));
+    QCOMPARE(myItem->height(), 300); // make sure the original value was restored
+
+    myItem->setProperty("when", QVariant(true));
+    QCOMPARE(myItem->height(), 100); // make sure the value specified in Binding is set
+    rect->setProperty("boundValue", 200);
+    QCOMPARE(myItem->height(), 200); // make sure the changed binding value is set
+    myItem->setProperty("when", QVariant(false));
+    // make sure that the original value is back, not e.g. the value from before the
+    // change (i.e. 100)
+    QCOMPARE(myItem->height(), 300);
+}
+
+void tst_qqmlbinding::restoreBindingVarValue()
+{
+    QQmlEngine engine;
+    QQmlComponent c(&engine, testFileUrl("restoreBinding3.qml"));
+    QScopedPointer<QQuickRectangle> rect(qobject_cast<QQuickRectangle*>(c.create()));
+    QVERIFY(!rect.isNull());
+
+    auto myItem = qobject_cast<QQuickRectangle*>(rect->findChild<QQuickRectangle*>("myItem"));
+    QVERIFY(myItem != nullptr);
+
+    QCOMPARE(myItem->property("foo"), 13);
+    myItem->setProperty("when", QVariant(false));
+    QCOMPARE(myItem->property("foo"), 42); // make sure the original value was restored
+
+    myItem->setProperty("when", QVariant(true));
+    QCOMPARE(myItem->property("foo"), 13); // make sure the value specified in Binding is set
+    rect->setProperty("boundValue", 31337);
+    QCOMPARE(myItem->property("foo"), 31337); // make sure the changed binding value is set
+    myItem->setProperty("when", QVariant(false));
+    // make sure that the original value is back, not e.g. the value from before the
+    // change (i.e. 100)
+    QCOMPARE(myItem->property("foo"), 42);
+}
+
+void tst_qqmlbinding::restoreBindingJSValue()
+{
+    QQmlEngine engine;
+    QQmlComponent c(&engine, testFileUrl("restoreBinding4.qml"));
+    QScopedPointer<QQuickRectangle> rect(qobject_cast<QQuickRectangle*>(c.create()));
+    QVERIFY(!rect.isNull());
+
+    auto myItem = qobject_cast<QQuickRectangle*>(rect->findChild<QQuickRectangle*>("myItem"));
+    QVERIFY(myItem != nullptr);
+
+    QCOMPARE(myItem->property("fooCheck"), false);
+    myItem->setProperty("when", QVariant(false));
+    QCOMPARE(myItem->property("fooCheck"), true); // make sure the original value was restored
+
+    myItem->setProperty("when", QVariant(true));
+    QCOMPARE(myItem->property("fooCheck"), false); // make sure the value specified in Binding is set
+    rect->setProperty("boundValue", 31337);
+    QCOMPARE(myItem->property("fooCheck"), false); // make sure the changed binding value is set
+    myItem->setProperty("when", QVariant(false));
+    // make sure that the original value is back, not e.g. the value from before the change
+    QCOMPARE(myItem->property("fooCheck"), true);
+
+}
+
 void tst_qqmlbinding::restoreBindingWithLoop()
 {
     QQmlEngine engine;