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
17380	Default value of ModelAdmin.inlines can be altered.	Matthew Schinckel	nobody	"Because ModelAdmin.inlines is defined as an empty list, if you have not altered this in a ModelAdmin subclass, and then add to it, you actually add that inline to every ModelAdmin subclass that does not override inlines.

    class MyModelAdmin(admin.ModelAdmin):
        pass

    if 'other_app' in settings.INSTALLED_APPS:
        MyModelAdmin.inlines += [OtherInline]

This bug rears its head if you try to add two (or more) inlines to UserAdmin.

I do have what seems like a fix: in ModelAdmin.__init__(), we can do:

    self.inlines = self.inlines or []

This will set self.inlines to a new empty list if the original value was falsy."	Uncategorized	closed	contrib.admin	1.3	Normal	wontfix			Unreviewed	0	0	0	0	0	0