id	summary	reporter	owner	description	type	status	component	version	severity	resolution	keywords	cc	stage	has_patch	needs_docs	needs_tests	needs_better_patch	easy	ui_ux
9177	list_filter cannot filter nullable fields	Bob Thomas	nobody	"I have a model with a FloatField that is nullable. I would like to filter models that have that field set to null, so I added it to list_filter in my ModelAdmin class. When I select the ""None"" option, I get an exception from get_db_prep_value because it's calling float(None). I tried modifying get_db_prep_value for FloatField to return None if value is None or ""None"", which got rid of the exception, but did not return any results.

Will attach a patch if I figure out how to fix this to return correct results.

ForeignKey fields that are nullable do not even display a None option in the filter, but I get a similar error trying to modify the query string to use None instead of an id.
"		closed	contrib.admin	1.0		duplicate			Unreviewed	0	0	0	0	0	0