#29391: Postgres array lookups need to call get_db_prep_value to adapt values to
their db representation (FieldGetDbPrepValueMixin)
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Reporter: Gavin Wahl | Owner: (none)
Type: Uncategorized | Status: new
Component: contrib.postgres | Version: 2.0
Severity: Normal | Keywords:
Triage Stage: Unreviewed | Has patch: 0
Needs documentation: 0 | Needs tests: 0
Patch needs improvement: 0 | Easy pickings: 0
UI/UX: 0 |
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I have have a model that has an ArrayField of objects that need to be
adapted to database values (EnumField from https://github.com/hzdg/django-
enumfields).
The custom array lookups in django.contrib.postgres.arrays are not
correctly calling the base fields get_db_prep_value/get_prep_value before
passing the objects to the db api.
Repro:
{{{#!python
import enum
from django.db import models
from django.contrib.postgres.fields import ArrayField
class TestEnum(enum.Enum):
VALUE_1 = 'value_1'
class EnumField(models.CharField):
def get_prep_value(self, value):
if value is None:
return None
else:
return value.value
class TestModel(models.Model):
array_of_enums = ArrayField(EnumField(max_length=20))
TestModel.objects.filter(array_of_enums__contains=[TestEnum.VALUE_1])
}}}
Currently this fails with:
{{{
Traceback (most recent call last):
File "django/db/backends/utils.py", line 64, in execute
return self.cursor.execute(sql, params)
psycopg2.ProgrammingError: can't adapt type 'TestEnum'
The above exception was the direct cause of the following exception:
Traceback (most recent call last):
File "<console>", line 1, in <module>
File "django/db/models/query.py", line 226, in __repr__
data = list(self[:REPR_OUTPUT_SIZE + 1])
File "django/db/models/query.py", line 250, in __iter__
self._fetch_all()
File "django/db/models/query.py", line 1118, in _fetch_all
self._result_cache = list(self._iterable_class(self))
File "django/db/models/query.py", line 53, in __iter__
results = compiler.execute_sql(chunked_fetch=self.chunked_fetch)
File "django/db/models/sql/compiler.py", line 899, in execute_sql
raise original_exception
File "django/db/models/sql/compiler.py", line 889, in execute_sql
cursor.execute(sql, params)
File "django/db/backends/utils.py", line 79, in execute
return super(CursorDebugWrapper, self).execute(sql, params)
File "django/db/backends/utils.py", line 64, in execute
return self.cursor.execute(sql, params)
File "django/db/utils.py", line 94, in __exit__
six.reraise(dj_exc_type, dj_exc_value, traceback)
File "django/utils/six.py", line 685, in reraise
raise value.with_traceback(tb)
File "django/db/backends/utils.py", line 64, in execute
return self.cursor.execute(sql, params)
django.db.utils.ProgrammingError: can't adapt type 'TestEnum'
}}}
I expect it to succeed and generate a WHERE clause of `array_of_enums @>
ARRAY['value_1']`.
I think the fix is just to have the lookups inherit from
`FieldGetDbPrepValueMixin`.
--
Ticket URL: <https://code.djangoproject.com/ticket/29391>
Django <https://code.djangoproject.com/>
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