Admin's date list filter's "This month/year" and "Today" are incorrect when USE_TZ is set (with the postgres backend).

[Glenn Washburn <development@…>]

This may be applicable to other backends, but I'm not sure.

When using USE_TZ the backend connection is set to use UTC. So __year/__month/__day lookup filters will filter where the UTC timestamp has a year/month/day of the lookup value. However, what's really desired is to use the timestamp at the current timezone. For example, the current code when filtering for "today" datetimes which are not in UTC can potentially return a list of matching records where the set of days being displayed is more than one.

[Julien Phalip]

I haven't been able to review this fully but this seems like a potential release blocker.

[Anssi Kääriäinen]

This is related to #17260, if not duplicate. Fixing this generally is going to be probably somewhat hard. I have one idea, though: you could manually add/subtract the offset from the datetime when doing the filtering. It is not perfect (DST not taken into account correctly). But it might be easy enough to do for 1.4.

[Aymeric Augustin]

Indeed, this has the same root cause as #17260, which is a known limitation of the current implementation of time zone support.

Until now, #17260 didn't include "date_filter on a DateTimeField" in the list of problems; I've added it.

[Aymeric Augustin]

In fact, the patch I prepared for #17830 fixes this too.