Models: Straighten out model and modelData properties

If there is more than one role, just return the whole model item as
modelData. This makes sure we can always require modelData. That's a
basic precondition for writing delegates that work with any model.

The test shows that model and modelData behave quite erratically in the
different cases, but much of this cannot be changed anymore. At least
they are now both available in all cases.

Furthermore, provide modelData as anonymous property of model. This way,
if you have a model that can be singular, and a role that will be an
empty string if the model is singular, you can just write:

SomeDelegate {
    required property var model
    someData: model[role]
}

Task-number: QTBUG-111176
Task-number: QTBUG-110980
Task-number: QTBUG-104752
Change-Id: Ie200be467df2098d817b85b03d2409267722b596
Reviewed-by: Shawn Rutledge <shawn.rutledge@qt.io>

1 files changed, 1 insertions, 1 deletions

diff --git a/src/qml/jsruntime/qv4object.cpp b/src/qml/jsruntime/qv4object.cpp
index d58a712147..b3b907352b 100644
--- a/src/qml/jsruntime/qv4object.cpp
+++ b/src/qml/jsruntime/qv4object.cpp
@@ -177,7 +177,7 @@ void Object::defineAccessorProperty(StringOrSymbol *name, VTable::Call getter, V
     QV4::Scope scope(v4);
     ScopedProperty p(scope);
     QString n = name->toQString();
-    if (n.at(0) == QLatin1Char('@'))
+    if (!n.isEmpty() && n.at(0) == QLatin1Char('@'))
         n = QChar::fromLatin1('[') + QStringView{n}.mid(1) + QChar::fromLatin1(']');
     if (getter) {
         ScopedString getName(scope, v4->newString(QString::fromLatin1("get ") + n));