Spurious error when using label_tag of CheckboxSelectMultiple widget

[Mark Theng]

In the label_tag method of BoundField, if attrs == None and id_for_label == "" (as is possible with CheckboxSelectMultiple/RadioSelect), it is possible for the attrs passed into the context to be None. attrs.items is used directly in the attrs.html template without checking if attrs exists, resulting in the error django.template.base.VariableDoesNotExist: Failed lookup for key [items] in None.

This would be easily fixed by either passing attrs or {} into the context in the label_tag method, or adding an if attrs guard in attrs.html.

I have checked that this issue still exists on the main branch.

[Mariusz Felisiak]

Thanks for this report, however many templates, including some of the Django's templates, rely upon the silence of the template system when a nonexistent variable is encountered. I don't think it's worth tracking and changing them (see also #28526).