Ticket #13987: 13987_fix_2_with_tests.diff

django/db/models/options.py

@@ -113 +113 @@
                 # 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/models.py

@@ -137 +137 @@
 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()
+
 __test__ = {'API_TESTS':"""
 # Regression for #7350, #7202
 # Check that when you create a Parent object with a specific reference to an
@@ -386 +403 @@
 >>> p4.bachelorparty_set.all()
 [<BachelorParty: Bachelor party for Bob>, <BachelorParty: Bachelor party for Dave>]
 
+# Regression for #13987
+# Check that a primary key is defined for models that inherit from an abstract
+# model, which in turn inherits from a concrete model.
+>>> len([field for field in BusStation._meta.local_fields if field.primary_key])
+1
+>>> len([field for field in TrainStation._meta.local_fields if field.primary_key])
+1
+>>> BusStation._meta.pk.model is BusStation
+True
+>>> TrainStation._meta.pk.model is TrainStation
+True
+
 """}