Allow comparing CallableFalse/CallableTrue with bitwise or

[Tom Christie]

Original raised as a ticket in REST framework: ​https://github.com/tomchristie/django-rest-framework/issues/4439

Something that may confuse users calling .is_authenticated...

There's a slight difference in behavior between how the CallableFalse/CallableTrue instances behave compare to how False/True behave.

The Python boolean type happens to support the bitwise OR operator, and its behavior in this case is exactly equivalent to the or operator. Eg. False | True returns True

The backwards compat CallableFalse/CallableTrue instances do not support this usage, and will fail with eg. TypeError: unsupported operand type(s) for |: 'instance' and 'bool'

Their behavior is reasonable enough, and the user should really be using the boolean or operator, but we might introduce slightly less friction (ie don't raise a slightly opaque error message to the user) if we simply support and allow the bitwise operator in the same way as the boolean equivalents.

I'm probably a +0 on resolving this, as think it'd save a few folks a bit of head banging. Certainly wouldn't dispute a wontfix categorization.

Tip for easy pickings folks: Should be resolvable by including an __or__ method on the CallableFalse/CallableTrue classes.

[Baptiste Mispelon]

The change seems simple enough and I don't see any drawbacks to adding it.

If we can make our users' lives easier, I'm +1 on it.

If anyone is interested in tackling this, the CallableFalse/CallableTrue classes are defined in django/utils/deprecation.py.

Once the change is made, I think we should also discuss backporting it.

Thanks.

[Tim Graham]

The implementation can follow commit 54afa960d1ee8c63635225a0f0a2489971b5aab5.

[Olexander Yermakov]

Here is the ​PR. Thanks.

[Tim Graham <timograham@…>]

In b7fb6081:

Fixed #27154 -- Allowed comparing CallableBool with bitwise or.

Thanks Tim for the review.

[Tim Graham <timograham@…>]

In 7c57f5c:

[1.10.x] Fixed #27154 -- Allowed comparing CallableBool with bitwise or.

Thanks Tim for the review.

Backport of b7fb608142a0be568bc5dce952de5e6aefc2488c from master