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
4714	JSON serializer doesn't handle None primary keys correctly (has tests.)	phil.h.smith@…	Maciej Wiśniowski	"Seems conceptually similar to #2894.

If you serialize('json', [model]) a model with model.id == None, you will produce json containing ""pk"": ""None"" instead of ""pk"": null.  The offending line seems to be in django.core.serializers.python.Serializer.end_object, around line 29, when str(obj._get_pk_val()) is called (or this is intentional and the generated ""None"" needs to be handled further down the line).

Test cases attached.
"		closed	Core (Serialization)	dev		fixed	json serialization primary key None null		Ready for checkin	1	0	0	0	0	0