#30575: Union of TruncBase annotations with different tzinfo apply
`convert_value`
of last tzinfo.
-------------------------------------+-------------------------------------
Reporter: Jurgis Pralgauskis | Owner: nobody
Type: Bug | Status: new
Component: Database layer | Version: master
(models, ORM) |
Severity: Normal | Resolution:
Keywords: timezone, | Triage Stage:
TruncBase, Union, PostgreSQL | Unreviewed
Has patch: 0 | Needs documentation: 0
Needs tests: 0 | Patch needs improvement: 0
Easy pickings: 0 | UI/UX: 0
-------------------------------------+-------------------------------------
Changes (by Jurgis Pralgauskis):
* status: closed => new
* resolution: worksforme =>
Old description:
> {{{#!python
> class Message(models.Model):
> timestamp = models.DateTimeField(auto_now=True) # PostgreSQL,
> USE_TZ=True
> msg = models.CharField(max_length=254)
> timezone = models.CharField(max_length=64, default="UTC",
> help_text="pytz name")
> }}}
>
> {{{#!python
> def test_demo_bug(self):
> from ..models import Message
> import pytz
> from django.db.models.functions import Trunc, TruncSecond
> import mock
> from django.utils import timezone
>
> with patch.object(timezone, 'now',
> return_value=pytz.utc.localize(datetime(2017, 1, 1, 0, 0))):
>
> # we have info
> Message.objects.create( msg = "bar", timezone = 'UTC')
> Message.objects.create( msg = "foo", timezone =
> 'America/Los_Angeles')
>
> # we want to get it with "localized" timestamps:
> qs = Message.objects.all()
>
> partitions = [] # partition by timezones
> for tzname in ['UTC', 'America/Los_Angeles']:
> tz = pytz.timezone(tzname)
> _qs = qs.filter(timezone=tzname)
> _qs =
> _qs.annotate(trunc_local_time=TruncSecond('timestamp', tzinfo=tz)) #
> could be Trunc_anything_
> partitions.append(_qs)
>
> qs1, qs2 = partitions
>
> result = list(qs1.union(qs2))
>
> for x in result:
> tz = pytz.timezone(x.timezone)
> print(x.msg)
> x.timestamp_trunc = x.timestamp.replace(microsecond=0)
> x.expected = x.timestamp_trunc.astimezone(tz) # this is
> the working way (but I wanted to get localization in DB layer)
> assert x.trunc_local_time == x.expected, "Error (msg:
> '{x.msg}'): {x.trunc_local_time} != {x.expected}".format(x=x)
>
> }}}
>
> {{{
> Failure
> Traceback (most recent call last):
> File "/home/jurgis/dev/new/tableair/sync_tableair-
> cloud/ta/api/booking/tests/test_endpoints.py", line 1107, in
> test_demo_bug
> assert x.trunc_local_time == x.expected, "Error (msg: '{x.msg}'):
> {x.trunc_local_time} != {x.expected}".format(x=x)
> AssertionError: Error (msg: 'bla'): 2016-12-31 16:00:00+00:00 !=
> 2017-01-01 00:00:00+00:00}}}
New description:
{{{#!python
class Message(models.Model):
timestamp = models.DateTimeField(auto_now=True) # PostgreSQL,
USE_TZ=True
msg = models.CharField(max_length=254)
timezone = models.CharField(max_length=64, default="UTC",
help_text="pytz name")
}}}
{{{#!python
def test_demo_bug(self):
from ..models import Message
import pytz
from django.db.models.functions import Trunc, TruncSecond
import mock
from django.utils import timezone
with patch.object(timezone, 'now',
return_value=pytz.utc.localize(datetime(2017, 1, 1, 0, 0))):
# we have info
Message.objects.create( msg = "bar", timezone = 'UTC')
Message.objects.create( msg = "foo", timezone =
'America/Los_Angeles')
# we want to get it with "localized" timestamps:
qs = Message.objects.all()
partitions = [] # partition by timezones
for tzname in ['UTC', 'America/Los_Angeles']:
tz = pytz.timezone(tzname)
_qs = qs.filter(timezone=tzname) # was but in test
hardcoded "UTC" instead of `tzname`
_qs =
_qs.annotate(trunc_local_time=TruncSecond('timestamp', tzinfo=tz)) # could
be Trunc_anything_
partitions.append(_qs)
qs1, qs2 = partitions
result = list(qs1.union(qs2))
for x in result:
tz = pytz.timezone(x.timezone)
print(x.msg)
x.timestamp_trunc = x.timestamp.replace(microsecond=0)
x.expected = x.timestamp_trunc.astimezone(tz) # this is
the working way (but I wanted to get localization in DB layer)
assert x.trunc_local_time == x.expected, "Error (msg:
'{x.msg}'): {x.trunc_local_time} != {x.expected}".format(x=x)
}}}
Problem - different TZ offsets
{{{
Failure
Traceback (most recent call last):
File "/home/jurgis/dev/new/tableair/sync_tableair-
cloud/ta/api/bookables/tests/test_endpoints.py", line 689, in
test_demo_bug
assert x.trunc_local_time == x.expected, "Error (msg: '{x.msg}'):
{x.trunc_local_time} != {x.expected}".format(x=x)
AssertionError: Error (msg: 'foo'): 2016-12-31 16:00:00+00:00 !=
2016-12-31 16:00:00-08:00
}}}
--
Comment:
Sorry, was a bug in my test, and failure didn't show up (probalby copied
wrong revision here)..
The SQL is generated OK, but imo, the problem is that
`TruncBase#convert_value` has the lines
{{{
value = value.replace(tzinfo=None)
value = timezone.make_aware(value, self.tzinfo)
}}}
they apply the same `tzinfo` to all (union'ed) rows (that come from
different timezones)
--
Ticket URL: <https://code.djangoproject.com/ticket/30575#comment:7>
Django <https://code.djangoproject.com/>
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