| Subject: | Getting 0 instead of NULL from form_has_a |
The updates post-0.47 to allow form_has_a to support nullable columns,
are inserting 0 instead of NULL when the NULL option is selected.
This subsequently breaks link_view, because an empty object is retrieved
(ID 0, doesn't actually exist in the related table, but an empty object
gets built). If the column was NULL, nothing would get retrieved and
there'd be no link to build.