[patch] ValueError on form.save() for form_for_model and form_for_instance with ManyToManyField

[jhilyard@…]

The database API wants a list of related object instances, not the list of primary key values supplied by clean_data (actually integers as unicode strings) when you .save() a form_for_model or form_for_instance instance.

ValueError at /edit/news/2/
objects to add() must be Audience instances
Request Method: POST
Request URL: [my url]
Exception Type: ValueError
Exception Value: objects to add() must be Audience instances
Exception Location: /usr/lib/python2.4/site-packages/django/db/models/fields/related.py in _add_items, line 327

here are the relevant bits of the models:

class News(models.Model):

audiences = models.ManyToManyField(Audience,filter_interface=models.HORIZONTAL)

class Audience(models.Model):

name = models.CharField(maxlength=64,unique=True,db_index=True)

[Jeff Hilyard <jhilyard@…>]

Suggested patch

[Jeff Hilyard <jhilyard@…>]

This is a suggestion that works for me since I am an impatient person (and I have Deadlines!).

I have only tested it in the case where the form_for_model or _instance is invoked on the model that contains the ManyToManyField, so I can't comment on whether it works in the backwards relation case.

I love the work you guys are doing and can't wait for 1.0!

[Jeff Hilyard <jhilyard@…>]

I should have used "_default_manager" instead of "objects" in the new line 41 of the attached .diff

[(none)]

Milestone Version 1.0 deleted

[Chris Beaven]

Thanks for the initial patch, Jeff.

[Adrian Holovaty]

(In [4439]) Fixed #3263 -- newforms form_for_model() and form_for_instance() now handle foreign-key and many-to-many data properly. Thanks for the patch, Jeff Hilyard