id	summary	reporter	owner	description	type	status	component	version	severity	resolution	keywords	cc	stage	has_patch	needs_docs	needs_tests	needs_better_patch	easy	ui_ux
22018	Checks error on ModelAdmins with multiple fields in one line using lists	Julian Wachholz	Julian Wachholz	"The checks framework will raise an error for ModelAdmin classes that use a `fields` or `fieldset` attribute containing multiple fields in one line -  
although only when using lists, using tuples works as expected.

Example:
{{{
class FooAdmin(admin.ModelAdmin):
    fields = ['foo', ['bar', 'baz']]

admin.site.register(Foo, FooAdmin)
}}}


Traceback:
{{{
  File ""/home/jwa/projects/django17/apps/foos/admin.py"", line 15, in <module>
    admin.site.register(Foo, FooAdmin)
  File ""/home/jwa/.venvs/django17/lib/python3.3/site-packages/django/contrib/admin/sites.py"", line 103, in register
    admin_class.check(model)
  File ""/home/jwa/.venvs/django17/lib/python3.3/site-packages/django/contrib/admin/options.py"", line 145, in check
    return cls.checks_class().check(cls, model, **kwargs)
  File ""/home/jwa/.venvs/django17/lib/python3.3/site-packages/django/contrib/admin/checks.py"", line 489, in check
    errors = super(ModelAdminChecks, self).check(cls, model=model, **kwargs)
  File ""/home/jwa/.venvs/django17/lib/python3.3/site-packages/django/contrib/admin/checks.py"", line 27, in check
    errors.extend(self._check_fields(cls, model))
  File ""/home/jwa/.venvs/django17/lib/python3.3/site-packages/django/contrib/admin/checks.py"", line 87, in _check_fields
    elif len(cls.fields) != len(set(cls.fields)):
TypeError: unhashable type: 'list'
}}}


So the `_check_fields` and `_check_fieldsets_item` checks need to take care of lists.
"	Bug	closed	contrib.admin	dev	Normal	fixed	checks		Accepted	0	0	0	0	1	0