Example in documentation saves an unbounded form

[alexpirine]

​https://docs.djangoproject.com/en/dev/topics/forms/modelforms/#the-save-method

This doesn't work:

>>> a = Article.objects.get(pk=1)
>>> f = ArticleForm(instance=a)
>>> f.save() # AttributeError: 'Article' object has no attribute 'cleaned_data'

Also confirmed here:

​http://stackoverflow.com/questions/2393348/django-form-error#comment2374980_2394120

and here:

​https://docs.djangoproject.com/en/dev/ref/forms/api/#behavior-of-unbound-forms

[phantummm]

The issue here seems to be that whoever wrote the example assumed, reasonably enough perhaps, that "instance=a" binds the form. But it appears that the given instance and its fields are used only for supplying the "initial" parameter to the BaseForm class, whereas BaseForm.is_bound is based only on the presence of the "data" and "files" parameters. This is why, looking at the example above:

>>> f = ArticleForm({'title':'...', 'body':'...'})
>>> f.save()
<Article: Article object>

...would work, saving the passed data as a new Article and binding it to the form.

[phantummm <phantummm@…>]

Pull-request here: ​https://github.com/django/django/pull/730

[Tim Graham <timograham@…>]

In a7358586e95016e414d90bccdff4675b1b65bbe3:

Merge pull request #730 from phantummm/ticket_19719

Fixed #19719 - Removed misleading example from ModelForm documentation

[Tim Graham <timograham@…>]

In 5c3c8bf09a986660fcd4421df38745167a10ba11:

[1.5.x] Fixed #19719 - Removed misleading example from ModelForm documentation

Backport of 976dc07baf from master

[Tim Graham <timograham@…>]

In 3d6388941d231e7ae1b5a53cdf2e401b704744b5:

[1.4.x] Fixed #19719 - Removed misleading example from ModelForm documentation

Backport of 976dc07baf from master