BooleanField: different behaviour when default=callable

[alex@…]

When using a callable, the behaviour of the BooleanField is different from just using a constant. Example:

foo = models.BooleanField(default=lambda: False)

vs.

foo = models.BooleanField(default=False)

[alex@…]

Oh, hit submit too fast. Basically, the callable-form emits, when used in a ModelForm (for example the admin), the following hidden initial-field:

<input type="hidden" name="initial-child1_set-0-foo" value="False" id="id_child1_set-0-foo" />

This has the effect that form.has_changed() is always True, so that extra forms of formsets are always considered for validation.

[alex@…]

Ok, I found out that I can work around by returning None instead of False from the callable, the value="" attribute is left out in the hidden initial. A possible fix would be to make the CheckboxInput widget accept u"False" as False in the _has_changed check, or by preventing the hidden initial field from having value="False" in the first place.

[SafPlusPlus <freark@…>]

Regression test for #10928

[SafPlusPlus <freark@…>]

Added a test, which is hopefully correct. Maybe I should've named the file in way that more reflects that it only contains a test and not a fix, but then again, I'm just a newbie so I may get away with it. :)

[Aymeric Augustin]

Change UI/UX from NULL to False.

[Aymeric Augustin]

Change Easy pickings from NULL to False.

[Markus Amalthea Magnuson]

This was fixed in ​https://github.com/django/django/commit/d11038acb2ea2f59a1d00a41b553f578b5f2c59c