Commit c402db2e authored by Simon Charette's avatar Simon Charette
Browse files

[1.9.x] Fixed #25882 -- Prevented fast deletes matching no rows from crashing on MySQL. 

Thanks to Trac aliases gerricom for the report, raphaelmerx for the
attempts to reproduce and Sergey Fedoseev and Tim for the review.

Refs #16891

Backport of 8035cee9 from master
parent 45ea0074

django/db/models/sql/subqueries.py

+1 −1
Original line number Diff line number Diff line
@@ -68,7 +68,7 @@ class DeleteQuery(Query): 
                # We can't do the delete using subquery.

                values = list(query.values_list('pk', flat=True))

                if not values:

                    return

                    return 0

                return self.delete_batch(values, using)

            else:

                innerq.clear_select_clause()

docs/releases/1.9.1.txt

+3 −0
Original line number Diff line number Diff line
@@ -34,3 +34,6 @@ Bugfixes 
  created by ``startapp`` on Python 2 (:ticket:`25909`). Add this line to your

  own ``apps.py`` files created using Django 1.9 if you want your migrations

  to work on both Python 2 and Python 3.



* Prevented ``QuerySet.delete()`` from crashing on MySQL when querying across

  relations (:ticket`25882`).

tests/delete/tests.py

+12 −0
Original line number Diff line number Diff line
@@ -502,3 +502,15 @@ class FastDeleteTests(TestCase): 
        # that + fast delete of the related objs.

        self.assertNumQueries(2, a.delete)

        self.assertEqual(User.objects.count(), 0)



    def test_fast_delete_empty_no_update_can_self_select(self):

        """

        #25932 - Fast deleting on backends that don't have the

        `no_update_can_self_select` feature should work even if the specified

        filter doesn't match any row.

        """

        with self.assertNumQueries(1):

            self.assertEqual(

                User.objects.filter(avatar__desc='missing').delete(),

                (0, {'delete.User': 0})

            )