QML: Before processing deep aliases, remove pending bindings

We may have additional bindings scheduled for the deep alias, but those
are to be overridden by the alias. They should therefore be removed like
bindings to target properties of shallow aliases.

For QProperty bindings we have to apply a separate trick and set and
clear the binding bit in the right places. We don't have access to the
actual binding when writing the value, after all.

Pick-to: 6.2
Fixes: QTBUG-115579
Change-Id: Ia915e59905d7e3185a17c5b6613926264ad9bc6b
Reviewed-by: Qt CI Bot <qt_ci_bot@qt-project.org>
Reviewed-by: Fabian Kosmale <fabian.kosmale@qt.io>
(cherry picked from commit 0fdf9042ce)
(cherry picked from commit c07f63d064)
Reviewed-by: Qt Cherry-pick Bot <cherrypick_bot@qt-project.org>

src/qml/qml/qqmlobjectcreator.cpp

@@ -913,10 +913,13 @@ bool QQmlObjectCreator::setPropertyBinding(const QQmlPropertyData *bindingProper
             && !(bindingFlags & QV4::CompiledData::Binding::IsPropertyObserver)
             && !_valueTypeProperty;
 
-    if (_ddata->hasBindingBit(bindingProperty->coreIndex()) && allowedToRemoveBinding) {
+    if (allowedToRemoveBinding) {
-        QQmlPropertyPrivate::removeBinding(_bindingTarget, QQmlPropertyIndex(bindingProperty->coreIndex()));
+        if (bindingProperty->isBindable()) {
-    } else if (bindingProperty->isBindable() && allowedToRemoveBinding) {
+            removePendingBinding(_bindingTarget, bindingProperty->coreIndex());
-        removePendingBinding(_bindingTarget, bindingProperty->coreIndex());
+        } else {
+            QQmlPropertyPrivate::removeBinding(
+                    _bindingTarget, QQmlPropertyIndex(bindingProperty->coreIndex()));
+        }
     }
 
     if (bindingType == QV4::CompiledData::Binding::Type_Script || binding->isTranslationBinding()) {
@@ -962,6 +965,9 @@ bool QQmlObjectCreator::setPropertyBinding(const QQmlPropertyData *bindingProper
                 qmlBinding = QQmlPropertyBinding::create(bindingProperty, runtimeFunction, _scopeObject, context, currentQmlContext(), _bindingTarget, index);
             }
             sharedState.data()->allQPropertyBindings.push_back(DeferredQPropertyBinding {_bindingTarget, bindingProperty->coreIndex(), qmlBinding });
+
+            QQmlData *data = QQmlData::get(_bindingTarget, true);
+            data->setBindingBit(_bindingTarget, bindingProperty->coreIndex());
         } else {
             // When writing bindings to grouped properties implemented as value types,
             // such as point.x: { someExpression; }, then the binding is installed on
@@ -1458,6 +1464,14 @@ bool QQmlObjectCreator::finalize(QQmlInstantiationInterrupt &interrupt)
 
     while (!sharedState->allQPropertyBindings.isEmpty()) {
         auto& [target, index, qmlBinding] = sharedState->allQPropertyBindings.first();
+
+        QQmlData *data = QQmlData::get(target);
+        if (!data || !data->hasBindingBit(index)) {
+            // The target property has been overwritten since we stashed the binding.
+            sharedState->allQPropertyBindings.pop_front();
+            continue;
+        }
+
         QUntypedBindable bindable;
         void *argv[] = { &bindable };
         // allow interception

src/qml/qml/qqmlvmemetaobject.cpp

@@ -1031,15 +1031,20 @@ int QQmlVMEMetaObject::metaCall(QObject *o, QMetaObject::Call c, int _id, void *
                 int coreIndex = encodedIndex.coreIndex();
                 const int valueTypePropertyIndex = encodedIndex.valueTypeIndex();
 
-                // Remove binding (if any) on write
+                const auto removePendingBinding
-                if(c == QMetaObject::WriteProperty) {
+                        = [c, a](QObject *target, int coreIndex, QQmlPropertyIndex encodedIndex) {
-                    int flags = *reinterpret_cast<int*>(a[3]);
+                    // Remove binding (if any) on write
-                    if (flags & QQmlPropertyData::RemoveBindingOnAliasWrite) {
+                    if (c == QMetaObject::WriteProperty) {
-                        QQmlData *targetData = QQmlData::get(target);
+                        int flags = *reinterpret_cast<int*>(a[3]);
-                        if (targetData && targetData->hasBindingBit(coreIndex))
+                        if (flags & QQmlPropertyData::RemoveBindingOnAliasWrite) {
-                            QQmlPropertyPrivate::removeBinding(target, encodedIndex);
+                            QQmlData *targetData = QQmlData::get(target);
+                            if (targetData && targetData->hasBindingBit(coreIndex)) {
+                                QQmlPropertyPrivate::removeBinding(target, encodedIndex);
+                                targetData->clearBindingBit(coreIndex);
+                            }
+                        }
                     }
-                }
+                };
 
                 if (valueTypePropertyIndex != -1) {
                     if (!targetDData->propertyCache)
@@ -1049,6 +1054,7 @@ int QQmlVMEMetaObject::metaCall(QObject *o, QMetaObject::Call c, int _id, void *
                     QQmlGadgetPtrWrapper *valueType = QQmlGadgetPtrWrapper::instance(
                                 ctxt->engine(), pd->propType());
                     if (valueType) {
+                        removePendingBinding(target, coreIndex, encodedIndex);
                         valueType->read(target, coreIndex);
                         int rv = QMetaObject::metacall(valueType, c, valueTypePropertyIndex, a);
 
@@ -1061,10 +1067,14 @@ int QQmlVMEMetaObject::metaCall(QObject *o, QMetaObject::Call c, int _id, void *
                         // deep alias
                         void *argv[1] = { &target };
                         QMetaObject::metacall(target, QMetaObject::ReadProperty, coreIndex, argv);
+                        removePendingBinding(
+                                target, valueTypePropertyIndex,
+                                QQmlPropertyIndex(valueTypePropertyIndex));
                         return QMetaObject::metacall(target, c, valueTypePropertyIndex, a);
                     }
 
                 } else {
+                    removePendingBinding(target, coreIndex, encodedIndex);
                     return QMetaObject::metacall(target, c, coreIndex, a);
                 }
 

tests/auto/qml/qqmllanguage/data/DeepAliasOnIC.qml

@@ -2,6 +2,7 @@ import QtQml
 
 QtObject {
     id: root
+    objectName: "theRoot"
 
     component ObjectWithColor: QtObject {
         property string color
@@ -10,12 +11,14 @@ QtObject {
 
     property ObjectWithColor border: ObjectWithColor {
         id: border
+        objectName: root.objectName
         color: root.trueBorderColor
         varvar: root.trueBorderVarvar
     }
 
     readonly property rect readonlyRect: ({x: 12, y: 13, width: 14, height: 15})
 
+    property alias borderObjectName: border.objectName
     property alias borderColor: border.color
     property alias borderVarvar: border.varvar
     property alias readonlyRectX: root.readonlyRect.x

tests/auto/qml/qqmllanguage/data/deepAliasOnICUser.qml

@@ -1,6 +1,7 @@
 import QtQml
 
 DeepAliasOnIC {
+    borderObjectName: "theLeaf"
     borderColor: "black"
     borderVarvar: "mauve"
 }

tests/auto/qml/qqmllanguage/tst_qqmllanguage.cpp

@@ -8125,15 +8125,11 @@ void tst_qqmllanguage::deepAliasOnICOrReadonly()
     QScopedPointer<QObject> o(c.create());
     QVERIFY(!o.isNull());
 
-    // We are mostly testing that it doesn't crash here. The actual bug is fixed separately.
-
-    QEXPECT_FAIL("", "QTBUG-115579 is not fixed yet", Continue);
     QCOMPARE(o->property("borderColor").toString(), QLatin1String("black"));
+    QCOMPARE(o->property("borderObjectName").toString(), QLatin1String("theLeaf"));
 
     const QVariant var = o->property("borderVarvar");
-    QEXPECT_FAIL("", "QTBUG-115579 is not fixed yet", Continue);
     QCOMPARE(var.metaType(), QMetaType::fromType<QString>());
-    QEXPECT_FAIL("", "QTBUG-115579 is not fixed yet", Continue);
     QCOMPARE(var.toString(), QLatin1String("mauve"));
 
     QQmlComponent c2(&engine, testFileUrl("deepAliasOnReadonly.qml"));