#31919: Django fails with FieldError: Expression contains mixed types:
IntegerField, AutoField. You must set output_field.
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Reporter: StefanosChaliasos | Owner: nobody
Type: Uncategorized | Status: new
Component: Uncategorized | Version: master
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 the following query.
{{{
expr = Value(3) * F('id')
o = Model.objects.using('default')
res = o.values('field_name').annotate(expr=expr).values('expr')
print(res)
}}}
Unfortunately, this query crashes with a FieldError exception. The track
trace is
{{{
Traceback (most recent call last):
File "example.py", line 28, in <module>
print(res)
File "/home/.env/lib/python3.6/site-
packages/Django-3.2-py3.6.egg/django/db/models/query.py", line 287, in
__iter__
self._fetch_all()
File "/home/.env/lib/python3.6/site-
packages/Django-3.2-py3.6.egg/django/db/models/query.py", line 1316, in
_fetch_all
self._result_cache = list(self._iterable_class(self))
File "/home/.env/lib/python3.6/site-
packages/Django-3.2-py3.6.egg/django/db/models/query.py", line 111, in
__iter__
for row in compiler.results_iter(chunked_fetch=self.chunked_fetch,
chunk_size=self.chunk_size):
File "/home/.env/lib/python3.6/site-
packages/Django-3.2-py3.6.egg/django/db/models/sql/compiler.py", line
1115, in results_iter
results = self.execute_sql(MULTI, chunked_fetch=chunked_fetch,
chunk_size=chunk_size)
File "/home/.env/lib/python3.6/site-
packages/Django-3.2-py3.6.egg/django/db/models/sql/compiler.py", line
1147, in execute_sql
sql, params = self.as_sql()
File "/home/.env/lib/python3.6/site-
packages/Django-3.2-py3.6.egg/django/db/models/sql/compiler.py", line 498,
in as_sql
extra_select, order_by, group_by = self.pre_sql_setup()
File "/home/.env/lib/python3.6/site-
packages/Django-3.2-py3.6.egg/django/db/models/sql/compiler.py", line 55,
in pre_sql_setup
self.setup_query()
File "/home/.env/lib/python3.6/site-
packages/Django-3.2-py3.6.egg/django/db/models/sql/compiler.py", line 46,
in setup_query
self.select, self.klass_info, self.annotation_col_map =
self.get_select()
File "/home/.env/lib/python3.6/site-
packages/Django-3.2-py3.6.egg/django/db/models/sql/compiler.py", line 267,
in get_select
sql, params = col.select_format(self, sql, params)
File "/home/.env/lib/python3.6/site-
packages/Django-3.2-py3.6.egg/django/db/models/expressions.py", line 385,
in select_format
if hasattr(self.output_field, 'select_format'):
File "/home/.env/lib/python3.6/site-
packages/Django-3.2-py3.6.egg/django/utils/functional.py", line 48, in
__get__
res = instance.__dict__[self.name] = self.func(instance)
File "/home/.env/lib/python3.6/site-
packages/Django-3.2-py3.6.egg/django/db/models/expressions.py", line 266,
in output_field
output_field = self._resolve_output_field()
File "/home/.env/lib/python3.6/site-
packages/Django-3.2-py3.6.egg/django/db/models/expressions.py", line 463,
in _resolve_output_field
return super()._resolve_output_field()
File "/home/.env/lib/python3.6/site-
packages/Django-3.2-py3.6.egg/django/db/models/expressions.py", line 306,
in _resolve_output_field
source.__class__.__name__,
django.core.exceptions.FieldError: Expression contains mixed types:
IntegerField, AutoField. You must set output_field.
}}}
This should be a regression bug because the previous query works in Django
3.1
--
Ticket URL: <https://code.djangoproject.com/ticket/31919>
Django <https://code.djangoproject.com/>
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