#34828: DateTimeField breaks when given datetime that would be invalid in UTC
-------------------------------------+-------------------------------------
Reporter: Denis | Owner: nobody
Cornehl |
Type: Bug | Status: new
Component: Database | Version: 4.2
layer (models, ORM) |
Severity: Normal | Keywords:
Triage Stage: | Has patch: 0
Unreviewed |
Needs documentation: 0 | Needs tests: 0
Patch needs improvement: 0 | Easy pickings: 0
UI/UX: 0 |
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We had a strange production error which I think is due to a Django bug,
but please correct me if I'm wrong :)
We have `USE_TZ` active, our own timezone set (Europe/Berlin), and a user
entered `0001-01-01 00:00:00` into a datetimefield in a form.
This value is now put into the postgres `timestamp with tz` field
including its timezone (` 0001-01-01 00:00:28+00:53:28` for example).
When I now try to read the model instance from the database, I'm getting a
`ValueError: year -1 is out of range ` exception:
{{{
File "[...]/lib/python3.11/site-packages/django/db/models/manager.py",
line 87, in manager_method
return getattr(self.get_queryset(), name)(*args, **kwargs)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "[...]/lib/python3.11/site-packages/django/db/models/query.py",
line 633, in get
num = len(clone)
^^^^^^^^^^
File "[...]/lib/python3.11/site-packages/django/db/models/query.py",
line 380, in __len__
self._fetch_all()
File "[...]/lib/python3.11/site-packages/django/db/models/query.py",
line 1881, in _fetch_all
self._result_cache = list(self._iterable_class(self))
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "[...]/lib/python3.11/site-packages/django/db/models/query.py",
line 91, in __iter__
results = compiler.execute_sql(
^^^^^^^^^^^^^^^^^^^^^
File "[...]/lib/python3.11/site-
packages/django/db/models/sql/compiler.py", line 1595, in execute_sql
return list(result)
^^^^^^^^^^^^
File "[...]/lib/python3.11/site-
packages/django/db/models/sql/compiler.py", line 2093, in cursor_iter
for rows in iter((lambda: cursor.fetchmany(itersize)), sentinel):
File "[...]/lib/python3.11/site-
packages/django/db/models/sql/compiler.py", line 2093, in <lambda>
for rows in iter((lambda: cursor.fetchmany(itersize)), sentinel):
^^^^^^^^^^^^^^^^^^^^^^^^^^
File "[...]/lib/python3.11/site-packages/django/db/utils.py", line 98,
in inner
return func(*args, **kwargs)
^^^^^^^^^^^^^^^^^^^^^
ValueError: year -1 is out of range
}}}
I'm aware that the postgres timestamp supports a wider range than the
python datetime, but then I would have assumed that the field wouldn't
even accept values it can't handle.
In this specific case I see that we have a timezone aware datetime in
python, store it into the database with timezone, and `psycopg2` fetches
it as timezone aware datetime. So I'm not sure why it has to be valid in
UTC too.
This can be reproduced using a simple model:
{{{#!python
class TestModel(models.Model):
d = models.DateTimeField()
}}}
And the following code:
{{{#!python
from brokendate.models import TestModel
from datetime import datetime, date
from pytz import timezone
TestModel.objects.all().delete()
ok = datetime(1,1,1, 0,0,0, tzinfo=timezone("Europe/Berlin"))
t = TestModel()
# assign datetime that would be invalid in UTC
t.d = ok
t.save()
print("fetch object")
# this raises the exception
t = TestModel.objects.get()
print(t.d)
}}}
I've created a small django project / app with a `break` management
command that will reproduce this problem.
--
Ticket URL: <https://code.djangoproject.com/ticket/34828>
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