[1.0.X] Fixed #10251 -- Fixed model inheritance when there's also an explicit pk field.

Backport of r9970 from trunk.

git-svn-id: http://code.djangoproject.com/svn/django/branches/releases/1.0.X@9972 bcc190cf-cafb-0310-a4f2-bffc1f526a37

3 files changed, 38 insertions, 4 deletions

diff --git a/django/db/models/options.py b/django/db/models/options.py
index 5d8a7b7104..292de67910 100644
--- a/django/db/models/options.py
+++ b/django/db/models/options.py
@@ -436,6 +436,21 @@ class Options(object):
             result.update(parent._meta.get_parent_list())
         return result
 
+    def get_ancestor_link(self, ancestor):
+        """
+        Returns the field on the current model which points to the given
+        "ancestor". This is possible an indirect link (a pointer to a parent
+        model, which points, eventually, to the ancestor). Used when
+        constructing table joins for model inheritance.
+
+        Returns None if the model isn't an ancestor of this one.
+        """
+        if ancestor in self.parents:
+            return self.parents[ancestor]
+        for parent in self.parents:
+            if parent._meta.get_ancestor_link(ancestor):
+                return self.parents[parent]
+
     def get_ordered_objects(self):
         "Returns a list of Options objects that are ordered with respect to this object."
         if not hasattr(self, '_ordered_objects'):
diff --git a/django/db/models/sql/query.py b/django/db/models/sql/query.py
index c8c25bd711..550e6e323c 100644
--- a/django/db/models/sql/query.py
+++ b/django/db/models/sql/query.py
@@ -494,14 +494,14 @@ class BaseQuery(object):
         aliases = set()
         if start_alias:
             seen = {None: start_alias}
-            root_pk = opts.pk.column
         for field, model in opts.get_fields_with_model():
             if start_alias:
                 try:
                     alias = seen[model]
                 except KeyError:
+                    link_field = opts.get_ancestor_link(model)
                     alias = self.join((start_alias, model._meta.db_table,
-                            root_pk, model._meta.pk.column))
+                            link_field.column, model._meta.pk.column))
                     seen[model] = alias
             else:
                 # If we're starting from the base model of the queryset, the
@@ -1005,13 +1005,13 @@ class BaseQuery(object):
         as_sql()).
         """
         opts = self.model._meta
-        root_pk = opts.pk.column
         root_alias = self.tables[0]
         seen = {None: root_alias}
         for field, model in opts.get_fields_with_model():
             if model not in seen:
+                link_field = opts.get_ancestor_link(model)
                 seen[model] = self.join((root_alias, model._meta.db_table,
-                        root_pk, model._meta.pk.column))
+                        link_field.column, model._meta.pk.column))
         self.included_inherited_models = seen
 
     def remove_inherited_models(self):
diff --git a/tests/regressiontests/model_inheritance_regress/models.py b/tests/regressiontests/model_inheritance_regress/models.py
index b5c051d5ca..d2fa4cbf15 100644
--- a/tests/regressiontests/model_inheritance_regress/models.py
+++ b/tests/regressiontests/model_inheritance_regress/models.py
@@ -86,6 +86,19 @@ class Evaluation(Article):
 class QualityControl(Evaluation):
     assignee = models.CharField(max_length=50)
 
+class BaseM(models.Model):
+    base_name = models.CharField(max_length=100)
+
+    def __unicode__(self):
+        return self.base_name
+
+class DerivedM(BaseM):
+    customPK = models.IntegerField(primary_key=True)
+    derived_name = models.CharField(max_length=100)
+
+    def __unicode__(self):
+        return "PK = %d, base_name = %s, derived_name = %s" \
+                % (self.customPK, self.base_name, self.derived_name)
 
 __test__ = {'API_TESTS':"""
 # Regression for #7350, #7202
@@ -275,4 +288,10 @@ True
 >>> ArticleWithAuthor.objects.filter(pk=article.pk).update(headline="Oh, no!")
 1
 
+>>> DerivedM.objects.create(customPK=44, base_name="b1", derived_name="d1")
+<DerivedM: PK = 44, base_name = b1, derived_name = d1>
+>>> DerivedM.objects.all()
+[<DerivedM: PK = 44, base_name = b1, derived_name = d1>]
+
 """}
+