make_aware throws AmbiguousTimeError exception

[trott@…]

When using the pytz package, the make_aware() utility function occasionally throws an AmbiguousTimeError or NonExistentTimeError exception.
As the pytz maintainer explain, some dates time values may not be localizable (using the pytz.localize() function) when the optional is_dst Parameter is
None.

I don't think, that Django should throw an exception in these cases, that results in a "show stopper" behavior.
Instead, I would prefer to just "guess" it the is_dst parameter when these Exceptions occur. That may result in a 50% chance to get a 1 hour
miscalculation – but until we don't know a better way, I just prefer that instead of having some values not saved at all...

Anyway, I attached a little patch to prevent this nasty Exceptions.

[trott@…]

patch for utils/timezone.py

[Aymeric Augustin]

% python -m this | grep ambiguity
In the face of ambiguity, refuse the temptation to guess.

[Josh Smeaton]

​https://github.com/django/django/pull/4416

[Tim Graham <timograham@…>]

In 143255c8:

Fixed #22598 -- Allowed make_aware() to work with ambiguous datetime