#25609: Add a more useful error message for invalid nested lookup on a related
field
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Reporter: Ian-Foote | Owner: nobody
Type: Cleanup/optimization | Status: new
Component: Database layer (models, ORM) | Version: master
Severity: Normal | Keywords:
Triage Stage: Unreviewed | Has patch: 1
Easy pickings: 0 | UI/UX: 0
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If I have two models:
{{{#!python
class Author(models.Model):
name = models.CharField(max_length=255)
class Article(models.Model):
author = models.ForeignKey(Author)
}}}
and I make the following invalid query:
{{{#!python
Article.objects.filter(author__editor__name='James')
}}}
I get the unhelpful:
{{{#!python
Article.objects.filter(author__editor__name='James')
File "django/db/models/manager.py", line 125, in manager_method
return getattr(self.get_queryset(), name)(*args, **kwargs)
File "django/db/models/query.py", line 783, in filter
return self._filter_or_exclude(False, *args, **kwargs)
File "django/db/models/query.py", line 801, in _filter_or_exclude
clone.query.add_q(Q(*args, **kwargs))
File "django/db/models/sql/query.py", line 1239, in add_q
clause, _ = self._add_q(q_object, self.used_aliases)
File "django/db/models/sql/query.py", line 1265, in _add_q
allow_joins=allow_joins, split_subq=split_subq,
File "django/db/models/sql/query.py", line 1189, in build_filter
assert len(lookups) == 1
AssertionError
}}}
I propose making the error instead:
{{{#!python
TypeError: Related Field got invalid lookup: editor
}}}
Which matches that caused by:
{{{#!python
Article.objects.filter(author__editor='James')
}}}
--
Ticket URL: <https://code.djangoproject.com/ticket/25609>
Django <https://code.djangoproject.com/>
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