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>

4 files changed, 10 insertions, 0 deletions

diff --git a/src/qml/qml/qqmlincubator.cpp b/src/qml/qml/qqmlincubator.cpp
index 7b3ae31c08..5c3ecbfb60 100644
--- a/src/qml/qml/qqmlincubator.cpp
+++ b/src/qml/qml/qqmlincubator.cpp
@@ -690,6 +690,11 @@ RequiredProperties &QQmlIncubatorPrivate::requiredProperties()
     return creator->requiredProperties();
 }
 
+bool QQmlIncubatorPrivate::hadRequiredProperties() const
+{
+    return creator->componentHadRequiredProperties();
+}
+
 /*!
 Stores a mapping from property names to initial values with which the incubated
 component will be initialized
diff --git a/src/qml/qml/qqmlincubator_p.h b/src/qml/qml/qqmlincubator_p.h
index 731db7aad3..aadb147bd5 100644
--- a/src/qml/qml/qqmlincubator_p.h
+++ b/src/qml/qml/qqmlincubator_p.h
@@ -108,6 +108,7 @@ public:
     void forceCompletion(QQmlInstantiationInterrupt &i);
     void incubate(QQmlInstantiationInterrupt &i);
     RequiredProperties &requiredProperties();
+    bool hadRequiredProperties() const;
 };
 
 QT_END_NAMESPACE
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, {}});
         }
diff --git a/src/qml/qml/qqmlobjectcreator_p.h b/src/qml/qml/qqmlobjectcreator_p.h
index ee1d82d4e3..c302660799 100644
--- a/src/qml/qml/qqmlobjectcreator_p.h
+++ b/src/qml/qml/qqmlobjectcreator_p.h
@@ -126,6 +126,7 @@ public:
     QFiniteStack<QPointer<QObject> > &allCreatedObjects() { return sharedState->allCreatedObjects; }
 
     RequiredProperties &requiredProperties() {return sharedState->requiredProperties;}
+    bool componentHadRequiredProperties() const {return hadRequiredProperties;}
 
 private:
     QQmlObjectCreator(QQmlContextData *contextData, const QQmlRefPointer<QV4::ExecutableCompilationUnit> &compilationUnit, QQmlObjectCreatorSharedState *inheritedSharedState);
@@ -172,6 +173,7 @@ private:
     const QQmlPropertyCacheVector *propertyCaches;
     QExplicitlySharedDataPointer<QQmlObjectCreatorSharedState> sharedState;
     bool topLevelCreator;
+    bool hadRequiredProperties;
     QQmlIncubatorPrivate *incubator;
 
     QObject *_qobject;