Commit eb7a329f authored by Simon Charette's avatar Simon Charette
Browse files

[1.9.x] Fixed #25685 -- Fixed a duplicate query regression on deletion of proxied models. 

Thanks to Trac alias ppetrid for the report and Tim for the review.

Conflicts:
	tests/delete/tests.py

Forward port of 7c3ef199 from stable/1.8.x
parent c598dfa8

django/db/models/deletion.py

+2 −2
Original line number Diff line number Diff line
@@ -58,9 +58,9 @@ def get_candidate_relations_to_delete(opts): 
    candidate_models = {opts}

    candidate_models = candidate_models.union(opts.concrete_model._meta.proxied_children)

    # For each model, get all candidate fields.

    candidate_model_fields = chain.from_iterable(

    candidate_model_fields = set(chain.from_iterable(

        opts.get_fields(include_hidden=True) for opts in candidate_models

    )

    ))

    # The candidate relations are the ones that come from N-1 and 1-1 relations.

    # N-N  (i.e., many-to-many) relations aren't candidates for deletion.

    return (

docs/releases/1.8.7.txt

+3 −0
Original line number Diff line number Diff line
@@ -39,3 +39,6 @@ Bugfixes 


* Fixed ``Model.refresh_from_db()`` updating of ``ForeignKey`` fields with

  ``on_delete=models.SET_NULL`` (:ticket:`25715`).



* Fixed a duplicate query regression in 1.8 on proxied model deletion

  (:ticket:`25685`).

tests/delete/models.py

+6 −0
Original line number Diff line number Diff line
@@ -99,6 +99,12 @@ class Avatar(models.Model): 
    desc = models.TextField(null=True)





# This model is used to test a duplicate query regression (#25685)

class AvatarProxy(Avatar):

    class Meta:

        proxy = True





class User(models.Model):

    avatar = models.ForeignKey(Avatar, models.CASCADE, null=True)

tests/delete/tests.py

+11 −0
Original line number Diff line number Diff line
@@ -413,6 +413,17 @@ class DeletionTests(TestCase): 
        for k, v in existed_objs.items():

            self.assertEqual(deleted_objs[k], v)



    def test_proxied_model_duplicate_queries(self):

        """

        #25685 - Deleting instances of a model with existing proxy

        classes should not issue multiple queries during cascade

        deletion of referring models.

        """

        avatar = Avatar.objects.create()

        # One query for the Avatar table and a second for the User one.

        with self.assertNumQueries(2):

            avatar.delete()





class FastDeleteTests(TestCase):