Ticket #13987: 13987_fix_2_with_tests_updated.diff

django/db/models/options.py

@@ -119 +119 @@
                 # Promote the first parent link in lieu of adding yet another
                 # field.
                 field = self.parents.value_for_index(0)
+                already_created = [fld for fld in self.local_fields if fld.name == field.name]
+                if already_created:
+                    field = already_created[0]
                 field.primary_key = True
                 self.setup_pk(field)
             else:

tests/regressiontests/model_inheritance_regress/tests.py

@@ -11 +11 @@
     ParkingLot2, ParkingLot3, Supplier, Wholesaler, Child, SelfRefParent,
     SelfRefChild, ArticleWithAuthor, M2MChild, QualityControl, DerivedM,
     Person, BirthdayParty, BachelorParty, MessyBachelorParty,
-    InternalCertificationAudit)
+    InternalCertificationAudit, BusStation, TrainStation)
 
 
 class ModelInheritanceTest(TestCase):
@@ -386 +386 @@
             ],
             attrgetter("pk")
         )
+    
+    def test_13987(self):
+        """
+        Primary key set correctly with concrete->abstract->concrete inheritance.
+        """
+        # Regression test for #13987: Primary key is incorrectly determined
+        # when more than one model has a concrete->abstract->concrete
+        # inheritance hierarchy.
+        self.assertEquals(
+            len([field for field in BusStation._meta.local_fields
+                       if field.primary_key]),
+            1
+        )
+        self.assertEquals(
+            len([field for field in TrainStation._meta.local_fields
+                       if field.primary_key]),
+            1
+        )
+        self.assertIs(BusStation._meta.pk.model, BusStation)
+        self.assertIs(TrainStation._meta.pk.model, TrainStation)

tests/regressiontests/model_inheritance_regress/models.py

@@ -146 +146 @@
 
 class MessyBachelorParty(BachelorParty):
     pass
+
+# Check concrete -> abstract -> concrete inheritance
+class SearchableLocation(models.Model):
+    keywords = models.CharField(max_length=256)
+
+class Station(SearchableLocation):
+    name = models.CharField(max_length=128)
+    
+    class Meta:
+        abstract = True
+
+class BusStation(Station):
+    bus_routes = models.CommaSeparatedIntegerField(max_length=128)
+    inbound = models.BooleanField()
+
+class TrainStation(Station):
+    zone = models.IntegerField()