QML: Consider all possible metatypes when looking for attached props

metaObjectToType is in fact a MultiHash. There can be more than one QML
type associated with a given metaobject. Therefore, in order to find the
attached properties we need to iterate them.

This highlights a different problem: If you register the same metaobject
under different QML names and define different attached properties for
each, you will get random results here. That, however, is a problem of
the public qmlAttachedPropertiesObject function, which doesn't take a
parameter for the registered name of the type.

Change-Id: I0eb9618114029ef5000d8eb12691b7f8de485121
Reviewed-by: Simon Hausmann <simon.hausmann@qt.io>

1 files changed, 8 insertions, 5 deletions

diff --git a/src/qml/qml/qqmlmetatype.cpp b/src/qml/qml/qqmlmetatype.cpp
index 083917d20f..c05ae27b93 100644
--- a/src/qml/qml/qqmlmetatype.cpp
+++ b/src/qml/qml/qqmlmetatype.cpp
@@ -2150,11 +2150,14 @@ int QQmlMetaType::attachedPropertiesFuncId(QQmlEnginePrivate *engine, const QMet
     QMutexLocker lock(metaTypeDataLock());
     QQmlMetaTypeData *data = metaTypeData();
 
-    QQmlType type(data->metaObjectToType.value(mo));
-    if (type.attachedPropertiesFunction(engine))
-        return type.attachedPropertiesId(engine);
-    else
-        return -1;
+    for (auto it = data->metaObjectToType.constFind(mo), end = data->metaObjectToType.constEnd();
+         it != end && it.key() == mo; ++it) {
+        const QQmlType type(it.value());
+        if (type.attachedPropertiesFunction(engine))
+            return type.attachedPropertiesId(engine);
+    }
+
+    return -1;
 }
 
 QQmlAttachedPropertiesFunc QQmlMetaType::attachedPropertiesFuncById(QQmlEnginePrivate *engine, int id)