#29754: Trunc() doesn't handle NonExistentTimeError/AmbiguousTimeError
-------------------------------------+-------------------------------------
Reporter: Alexander Holmbäck | Owner: nobody
Type: Bug | Status: new
Component: Database layer | Version: master
(models, ORM) |
Severity: Normal | Resolution:
Keywords: pytz, Trunc() | Triage Stage:
| Unreviewed
Has patch: 0 | Needs documentation: 0
Needs tests: 0 | Patch needs improvement: 0
Easy pickings: 0 | UI/UX: 0
-------------------------------------+-------------------------------------
Description changed by Alexander Holmbäck:
Old description:
> When `Trunc()` truncates to a nonexisting or ambiguous datetime, the
> exception raised by pytz remains unhandled. The expected behavior would,
> IMO, be to use naive datetimes for truncated dates, or adjust to closest
> existing non-ambiguous datetime.
>
> This test for example:
> {{{#!python
> import datetime
> import pytz
>
> from django.db.models.functions import Trunc
> from django.test import TestCase
> from django.utils import timezone
>
> from .models import Log
>
> class TestTruncateToNonExistingTime(TestCase):
>
> def test_truncate_to_dst_ends_stockholm(self):
> tzinfo = pytz.timezone('Europe/Stockholm')
> timestamp = datetime.datetime(2018, 10, 28, 2, tzinfo=tzinfo)
> Log.objects.create(timestamp=timestamp)
> logs = Log.objects.annotate(day=Trunc('timestamp', 'hour')).all()
>
> timezone.activate(tzinfo)
> self.assertEqual(logs[0].day.day, 28)
> }}}
>
> Results in the following error:
> {{{
> ======================================================================
> ERROR: test_truncate_to_dst_ends_stockholm
> (trunc.tests.TestTruncateToNonExistingTime)
> ----------------------------------------------------------------------
> Traceback (most recent call last):
> File "/home/alex/tickets/trunc/tests.py", line 47, in
> test_truncate_to_dst_ends_stockholm
> self.assertEqual(logs[0].day.day, 28)
> File "/home/alex/django/django/db/models/query.py", line 303, in
> __getitem__
> qs._fetch_all()
> File "/home/alex/django/django/db/models/query.py", line 1190, in
> _fetch_all
> self._result_cache = list(self._iterable_class(self))
> File "/home/alex/django/django/db/models/query.py", line 64, in
> __iter__
> for row in compiler.results_iter(results):
> File "/home/alex/django/django/db/models/sql/compiler.py", line 1013,
> in apply_converters
> value = converter(value, expression, connection)
> File "/home/alex/django/django/db/models/functions/datetime.py", line
> 225, in convert_value
> value = timezone.make_aware(value, self.tzinfo)
> File "/home/alex/django/django/utils/timezone.py", line 270, in
> make_aware
> return timezone.localize(value, is_dst=is_dst)
> File "/home/alex/.virtualenvs/djangodev/lib/python3.6/site-
> packages/pytz/tzinfo.py", line 363, in localize
> raise AmbiguousTimeError(dt)
> pytz.exceptions.AmbiguousTimeError: 2018-10-28 02:00:00
> }}}
New description:
When `Trunc()` truncates to a nonexisting or ambiguous datetime, the
exception raised by pytz remains unhandled. The expected behavior would,
IMO, be to not check the validity of truncated dates.
This test for example:
{{{#!python
import datetime
import pytz
from django.db.models.functions import Trunc
from django.test import TestCase
from django.utils import timezone
from .models import Log
class TestTruncateToInvalidTime(TestCase):
def test_truncate_to_dst_ends_stockholm(self):
tzinfo = pytz.timezone('Europe/Stockholm')
timestamp = datetime.datetime(2018, 10, 28, 2, tzinfo=tzinfo)
Log.objects.create(timestamp=timestamp)
logs = Log.objects.annotate(day=Trunc('timestamp', 'hour')).all()
timezone.activate(tzinfo)
self.assertEqual(logs[0].day.day, 28)
}}}
Results in the following error:
{{{
======================================================================
ERROR: test_truncate_to_dst_ends_stockholm
(trunc.tests.TestTruncateInvalidTime)
----------------------------------------------------------------------
Traceback (most recent call last):
File "/home/alex/tickets/trunc/tests.py", line 47, in
test_truncate_to_dst_ends_stockholm
self.assertEqual(logs[0].day.day, 28)
File "/home/alex/django/django/db/models/query.py", line 303, in
__getitem__
qs._fetch_all()
File "/home/alex/django/django/db/models/query.py", line 1190, in
_fetch_all
self._result_cache = list(self._iterable_class(self))
File "/home/alex/django/django/db/models/query.py", line 64, in __iter__
for row in compiler.results_iter(results):
File "/home/alex/django/django/db/models/sql/compiler.py", line 1013, in
apply_converters
value = converter(value, expression, connection)
File "/home/alex/django/django/db/models/functions/datetime.py", line
225, in convert_value
value = timezone.make_aware(value, self.tzinfo)
File "/home/alex/django/django/utils/timezone.py", line 270, in
make_aware
return timezone.localize(value, is_dst=is_dst)
File "/home/alex/.virtualenvs/djangodev/lib/python3.6/site-
packages/pytz/tzinfo.py", line 363, in localize
raise AmbiguousTimeError(dt)
pytz.exceptions.AmbiguousTimeError: 2018-10-28 02:00:00
}}}
--
--
Ticket URL: <https://code.djangoproject.com/ticket/29754#comment:1>
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