Hi,
There is a inconsistency of how null is handled in
ChoiceRenderer#getIdValue and AbstractSingleSelectChoice#getModelValue.
ChoiceRenderer renders either "" as id, or index under which the null
value is in choices list.
AbstractSingleSelectChoice#getModelValue returns always -1 for null.
The outcome is that if RadioChoice has item with null value and the
model object is also null, the item is not pre-selected.
(because getValue() is compared to
getChoiceRenderer().getIdValue(choice, 0))
It is a bug, but I'm not sure what would be the best way to fix it.
Perhaps when AbstractSingleSelectChoice#isNullValid() is true the
getModelValue should call choiceRenderer.getIdValue(object, index) even
for null objects?
WDYT?
-Matej
