Deprecate Cache.has_key()?

[Tim Graham]

Any opposition to deprecating Cache.has_key()? Cache already implements __contains__() so converting has_key() to "in" can be done with existing versions of Django. Anyone using flake8 will get a warning about has_key() usage: W601 .has_key() is deprecated, use 'in'.


[Tim Graham]

Also the template BaseContext class has an undocumented has_key() method. I wonder if that can be removed without a deprecation?

https://github.com/django/django/pull/6066

[Curtis Maloney]

Isn't this so it complies with the dict interface? True, it's discouraged now, but it's still there.

--
Sent from my Android device with K-9 Mail. Please excuse my brevity.

[Tim Graham]

Yes, but dict.has_key() is removed in Python 3. If we started the deprecation in Django now, it would be scheduled for removal in Django 2.0 which also drops support for Python 2.

[Adam Johnson]

Might be problematic for third-party cache backends which implement has_key and rely on __contains__ calling it - don't see how you can show the warning in that case.

[Tim Graham]

We have django.utils.deprecation.RenameMethodsBase to help with that, but now I see that subclasses have this signature, `def has_key(self, key, version=None)`, so it doesn't seem the method can be replaced with __contains__.

Proposal withdrawn.