Support required properties in model delegates

If a delegates declares a required property of a given name, and that
name exists as a role in the model, we set the property accordingly.
The same holds true for the special properties that come from the
QQmlDelegateModel like "index" and "model".

All roles are still injected into scope and thus accessible;
changing this in Qt5 would be tedious or even impossible while still
maintaining backwardscompatibility with delegates that do not use
required properties.

Change-Id: I4f388ba549c42f1ff9822bdb3b8357c4d45e4b66
Reviewed-by: Ulf Hermann <ulf.hermann@qt.io>

1 files changed, 2 insertions, 0 deletions

diff --git a/src/qml/qml/qqmlobjectcreator.cpp b/src/qml/qml/qqmlobjectcreator.cpp
index b723ddb381..d2e9d36d55 100644
--- a/src/qml/qml/qqmlobjectcreator.cpp
+++ b/src/qml/qml/qqmlobjectcreator.cpp
@@ -82,6 +82,7 @@ QQmlObjectCreator::QQmlObjectCreator(QQmlContextData *parentContext, const QQmlR
     , propertyCaches(&compilationUnit->propertyCaches)
     , sharedState(new QQmlObjectCreatorSharedState)
     , topLevelCreator(true)
+    , hadRequiredProperties(false)
     , incubator(incubator)
 {
     init(parentContext);
@@ -1523,6 +1524,7 @@ bool QQmlObjectCreator::populateInstance(int index, QObject *instance, QObject *
         const QV4::CompiledData::Property* property = _compiledObject->propertiesBegin() + propertyIndex;
         QQmlPropertyData *propertyData = _propertyCache->property(_propertyCache->propertyOffset() + propertyIndex);
         if (property->isRequired) {
+            hadRequiredProperties = true;
             sharedState->requiredProperties.insert(propertyData,
                                                    RequiredPropertyInfo {compilationUnit->stringAt(property->nameIndex), compilationUnit->finalUrl(), property->location, {}});
         }