[1.6.x] Fixed #21405 -- Prevented queryset overwrite in BaseModelAdmin

Thanks guido@20tab.com for the report and Tim Graham for the
analyze.
Backport of 1718b5256c from master.

1 files changed, 22 insertions, 0 deletions

diff --git a/tests/admin_ordering/tests.py b/tests/admin_ordering/tests.py
index 6655ad37ad..083c053d66 100644
--- a/tests/admin_ordering/tests.py
+++ b/tests/admin_ordering/tests.py
@@ -148,6 +148,28 @@ class TestRelatedFieldsAdminOrdering(TestCase):
         # should be ordered by rank (defined by the ModelAdmin)
         self.check_ordering_of_field_choices([self.b1, self.b2])
 
+    def test_custom_queryset_still_wins(self):
+        """Test that custom queryset has still precedence (#21405)"""
+        class SongAdmin(admin.ModelAdmin):
+            # Exclude one of the two Bands from the querysets
+            def formfield_for_foreignkey(self, db_field, **kwargs):
+                if db_field.name == 'band':
+                    kwargs["queryset"] = Band.objects.filter(rank__gt=2)
+                return super(SongAdmin, self).formfield_for_foreignkey(db_field, **kwargs)
+            def formfield_for_manytomany(self, db_field, **kwargs):
+                if db_field.name == 'other_interpreters':
+                    kwargs["queryset"] = Band.objects.filter(rank__gt=2)
+                return super(SongAdmin, self).formfield_for_foreignkey(db_field, **kwargs)
+
+        class StaticOrderingBandAdmin(admin.ModelAdmin):
+            ordering = ('rank',)
+
+        admin.site.unregister(Song)
+        admin.site.register(Song, SongAdmin)
+        admin.site.register(Band, StaticOrderingBandAdmin)
+
+        self.check_ordering_of_field_choices([self.b2])
+
     def tearDown(self):
         admin.site.unregister(Song)
         if Band in admin.site._registry: