#27209: Cast function accepts field class according to docs but expects field
instance
----------------------------------------------+--------------------
Reporter: valentjedi | Owner: nobody
Type: Bug | Status: new
Component: Database layer (models, ORM) | Version: 1.10
Severity: Normal | Keywords:
Triage Stage: Unreviewed | Has patch: 0
Easy pickings: 0 | UI/UX: 0
----------------------------------------------+--------------------
Example from docs about `django.db.models.functions.Cast` will fail with
`TypeError: db_type() missing 1 required positional argument:
'connection'` because in `as_sql` method when adding db_type to
extra_context we execute db_type method of field class and not field
instance:
{{{
if 'db_type' not in extra_context:
extra_context['db_type'] = self._output_field.db_type(connection)
}}}
Here self._output_field is a class instead of instance. So we either must
pass an instance of field like
{{{
value = Value.objects.annotate(as_float=Cast('integer',
FloatField())).get()
}}}
and point to it in docs or create instance inside `as_sql` like this:
{{{
extra_context['db_type'] = self._output_field().db_type(connection)
}}}
--
Ticket URL: <https://code.djangoproject.com/ticket/27209>
Django <https://code.djangoproject.com/>
The Web framework for perfectionists with deadlines.
--
You received this message because you are subscribed to the Google Groups
"Django updates" group.
To unsubscribe from this group and stop receiving emails from it, send an email
to django-updates+unsubscr...@googlegroups.com.
To post to this group, send email to django-updates@googlegroups.com.
To view this discussion on the web visit
https://groups.google.com/d/msgid/django-updates/053.8f03fb821612b2043cf4bee11d1a36e2%40djangoproject.com.
For more options, visit https://groups.google.com/d/optout.
