#17118: list_editable will update wrong rows on a multiuser system if
pagination is
enabled
--------------------------------+------------------------------------------
Reporter: | Owner: nobody
emilianodelvalle@… | Status: new
Type: Bug | Version: 1.3
Component: contrib.admin | Keywords: list_editable list multiuser
Severity: Normal | Has patch: 0
Triage Stage: Unreviewed | UI/UX: 0
Easy pickings: 0 |
--------------------------------+------------------------------------------
If there is a model with fields which are "list editable" and the number
of rows for that model enables pagination, an update on those fields could
not work as expected (other rows are updated).
1. Lets say that the user updates fields on the first page on the change
list view.
2. While saving those changes, the information on the database changes
(another user or another process added rows that should be shown before
the rows updated by the user, shifting the rows modified by the user to a
second page).
3. Django will update the editable fields on the newest rows with the data
entered for other rows.
I debugged the code and I think that the bug is on the BaseModelFormSet.
For some reason, if it can't retrieve a instance model using the pk, it
will use the index to retrieve it. However, the queryset that it's using
has been limited by pagination. Therefore if the row updated has been
moved to another page, it won't be found.
This belongs to BaseModelFormSet, take a look at the final if on the
_construct_form method.
{{{
def _existing_object(self, pk):
if not hasattr(self, '_object_dict'):
self._object_dict = dict([(o.pk, o) for o in
self.get_queryset()])
return self._object_dict.get(pk)
def _construct_form(self, i, **kwargs):
if self.is_bound and i < self.initial_form_count():
# Import goes here instead of module-level because importing
# django.db has side effects.
from django.db import connections
pk_key = "%s-%s" % (self.add_prefix(i),
self.model._meta.pk.name)
pk = self.data[pk_key]
pk_field = self.model._meta.pk
pk = pk_field.get_db_prep_lookup('exact', pk,
connection=connections[self.get_queryset().db])
if isinstance(pk, list):
pk = pk[0]
kwargs['instance'] = self._existing_object(pk)
if i < self.initial_form_count() and not kwargs.get('instance'):
kwargs['instance'] = self.get_queryset()[i]
return super(BaseModelFormSet, self)._construct_form(i, **kwargs)
}}}
--
Ticket URL: <https://code.djangoproject.com/ticket/17118>
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 post to this group, send email to django-updates@googlegroups.com.
To unsubscribe from this group, send email to
django-updates+unsubscr...@googlegroups.com.
For more options, visit this group at
http://groups.google.com/group/django-updates?hl=en.
