Fix Trunc database function with tzinfo parameter

[timgraham]

No description provided.

[WaVEV]

This line isn't reachable I think. If value were None, cannot be instance of date

[WaVEV]

I think this logic could be refactored
But dont know how, at least If value none, return

[WaVEV]

This part does two things, astimezone and time (one or none)
To check if they must be applied, an code like

if convert_to_tz and isinstance(value, datetime):
    if isinstance(self.output_type, DatetimeField | DateField | TimeField):
        value = value.astimezone(self.tzinfo)
    if isinstance(self.output_type, DateField):
        value = value.date()
    elif isinstance(self.output_field, TimeField):
        value = value.time()
return value
        

Does this code make sense?
I am assuming that datetimefield implies a datetime value

[timgraham]

Yes, that looks logically correct, but it doesn't short-circuit as much and therefore has some extra isinstance() calls in some cases. (By the way, here's the original method: https://github.com/django/django/blob/9d93e35c207a001de1aa9ca9165bdec824da9021/django/db/models/functions/datetime.py#L345-L364. As you said, there's at least the issue of the unneeded None check under isinstance(value, datetime) there.)

edit: Actually, it's not correct, .date() and .time() truncations are needed even when convert_to_tz=False.

[WaVEV]

Oh right. I think it could be "untabbed" but in that way the code isn't much simple

[WaVEV]

Is this setting needed to raise the exception?

[timgraham]

Yes, tzinfo is ignored if USE_TZ=False.