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
9889	Admin error when using extra fields on many-to-many relationships	Adrian Ribao	nobody	"http://docs.djangoproject.com/en/dev/topics/db/models/#extra-fields-on-many-to-many-relationships

I have created a models similar to the one in the docs. Previously the admin was working ok, but when I changed the model to include extra fields in the m2m relationship, the admin broke.

The models code:

{{{
class Coach(models.Model):
    user = models.OneToOneField(User)
    customers = models.ManyToManyField(User, related_name = 'customers', through='CustomerCoach')
    
class CustomerCoach(models.Model):
    user = models.ForeignKey(user)
    coach = models.ForeignKey(Coach)
    date_joined = models.DateTimeField()
}}}


The admin code:
{{{
class CustomersCoachAdmin(admin.ModelAdmin):
    pass
admin.site.register(CustomersCoachAdmin, CustomerCoach)
}}}

I get this error:

{{{
'MediaDefiningClass' object is not iterable
}}}
"		closed	contrib.admin	dev		invalid		aribao@…	Unreviewed	0	0	0	0	0	0