Fixed #4001 -- Added dynamic save_m2m method() to forms created with form_for_model and form_for_instance on save(commit=False).

git-svn-id: http://code.djangoproject.com/svn/django/trunk@5804 bcc190cf-cafb-0310-a4f2-bffc1f526a37

tests/modeltests/model_forms/models.py

@@ -332,6 +332,28 @@ Create a new article, with no categories, via the form.
 >>> new_art.categories.all()
 []
 
+Create a new article, with categories, via the form, but use commit=False.
+The m2m data won't be saved until save_m2m() is invoked on the form.
+>>> ArticleForm = form_for_model(Article)
+>>> f = ArticleForm({'headline': u'The walrus was Paul', 'pub_date': u'1967-11-01',
+...     'writer': u'1', 'article': u'Test.', 'categories': [u'1', u'2']})
+>>> new_art = f.save(commit=False)
+
+# Manually save the instance 
+>>> new_art.save()
+>>> new_art.id
+4
+
+# The instance doesn't have m2m data yet
+>>> new_art = Article.objects.get(id=4)
+>>> new_art.categories.all()
+[]
+
+# Save the m2m data on the form
+>>> f.save_m2m()
+>>> new_art.categories.all()
+[<Category: Entertainment>, <Category: It's a test>]
+
 Here, we define a custom Form. Because it happens to have the same fields as
 the Category model, we can use save_instance() to apply its changes to an
 existing Category instance.