Ticket #9848: filtered_update_fix.diff

django/db/models/sql/subqueries.py

@@ -170 +170 @@
         query.extra_select = {}
         first_table = query.tables[0]
         if query.alias_refcount[first_table] == 1:
-            # We can remove one table from the inner query.
+            # We can remove one table from the inner query.  Because the
+            # sub-select isn't selecting anything from the table being updated,
+            # the where clause may need to filter based on a foreign key being
+            # in the sub-select rather than its own primary key.
             query.unref_alias(first_table)
             for i in xrange(1, len(query.tables)):
                 table = query.tables[i]
@@ -178 +181 @@
                     break
             join_info = query.alias_map[table]
             query.select = [(join_info[RHS_ALIAS], join_info[RHS_JOIN_COL])]
+            for field in query.model._meta.fields:
+                if field.column == join_info[LHS_JOIN_COL]:
+                    # field is either a ForeignKey field refering to table or
+                    # the primary key of query.model.
+                    where_filter = '%s__in' % field.name
+                    break
             must_pre_select = False
         else:
             query.select = []
             query.add_fields([query.model._meta.pk.name])
+            where_filter = 'pk__in'
             must_pre_select = not self.connection.features.update_can_self_select
 
         # Now we adjust the current query: reset the where clause and get rid
@@ -194 +204 @@
             idents = []
             for rows in query.execute_sql(MULTI):
                 idents.extend([r[0] for r in rows])
-            self.add_filter(('pk__in', idents))
+            self.add_filter((where_filter, idents))
             self.related_ids = idents
         else:
             # The fast path. Filters and updates in one query.
-            self.add_filter(('pk__in', query))
+            self.add_filter((where_filter, query))
         for alias in self.tables[1:]:
             self.alias_refcount[alias] = 0
 

tests/regressiontests/queries/models.py

@@ -1021 +1021 @@
 # optimise the inner query without losing results.
 >>> Annotation.objects.exclude(tag__children__name="t2")
 [<Annotation: a2>]
+
+# Bug #9848
+# This is a little tricky to test because we have to make sure that the IDs
+# from different tables don't happen to match.
+>>> Ranking.objects.filter(author__name='a1')
+[<Ranking: 3: a1>]
+>>> Ranking.objects.filter(author__name='a1').update(rank='4')
+1
+>>> r = Ranking.objects.filter(author__name='a1')[0]
+>>> r.id
+3
+>>> r.author.id
+1
+>>> r.rank
+4
+>>> r.rank = 3
+>>> r.save()
+>>> Ranking.objects.all()
+[<Ranking: 3: a1>, <Ranking: 2: a2>, <Ranking: 1: a3>]
 """}
 
 # In Python 2.3 and the Python 2.6 beta releases, exceptions raised in __len__