LazyObject is missing __iter__

[Rik]

The LazyObject class in utils.functional (​https://github.com/django/django/blob/master/django/utils/functional.py#L235) is missing the __iter__ magic method.

Other dict related magic methods like __getitem__, __setitem__ and __delitem__ are supported but not __iter__. I can't think of a reason it isn't there and haven't been able to find discussions about it. The __getitem__, __setitem__ and __delitem__ were added in this ticket:

https://code.djangoproject.com/ticket/18447

I think they just forgot __iter__. I'm proposing to add this. If this is done, then tickets like these:

https://code.djangoproject.com/ticket/23783

Can be resolved with SimpleLazyObject (which implements LazyObject).

[Rik]

Created a pull request:

​https://github.com/django/django/pull/3541

[Tim Graham]

As I noted on the pull request, the new tests pass even before the fix is applied so either there is no issue here or the test needs to be modified to actually show what issue is fixed.

[Baptiste Mispelon]

Hi,

The feature looks reasonable but as noted by Tim, the tests need some improvement.

Thanks.

[Rik]

I updated my pull request, the test now fails when __iter__ is not implemented in LazyObject, so it's a good unit test now.

[Bas Peschier]

New tests check for __iter__ and fail with old implementation; commit message is fine, lgtm.

The old test was already covered by the actual tests for __getitem__.

[Baptiste Mispelon <bmispelon@…>]

In a5b225084f69e27b78fab0f2954fa9520656976e:

Fixed #23838 -- added missing __iter__ to LazyObject