Fixed #12937 -- Corrected the operation of select_related() when following an reverse relation on an inherited model. Thanks to subsume for the report.

git-svn-id: http://code.djangoproject.com/svn/django/trunk@12814 bcc190cf-cafb-0310-a4f2-bffc1f526a37

django/db/models/query.py

@@ -1113,7 +1113,7 @@ class EmptyQuerySet(QuerySet):
 
 
 def get_cached_row(klass, row, index_start, using, max_depth=0, cur_depth=0,
-                   requested=None, offset=0, only_load=None):
+                   requested=None, offset=0, only_load=None, local_only=False):
     """
     Helper function that recursively returns an object with the specified
     related attributes already populated.
@@ -1141,6 +1141,8 @@ def get_cached_row(klass, row, index_start, using, max_depth=0, cur_depth=0,
      * only_load - if the query has had only() or defer() applied,
        this is the list of field names that will be returned. If None,
        the full field list for `klass` can be assumed.
+     * local_only - Only populate local fields. This is used when building
+       following reverse select-related relations
     """
     if max_depth and requested is None and cur_depth > max_depth:
         # We've recursed deeply enough; stop now.
@@ -1153,9 +1155,11 @@ def get_cached_row(klass, row, index_start, using, max_depth=0, cur_depth=0,
         skip = set()
         init_list = []
         # Build the list of fields that *haven't* been requested
-        for field in klass._meta.fields:
+        for field, model in klass._meta.get_fields_with_model():
             if field.name not in load_fields:
                 skip.add(field.name)
+            elif local_only and model is not None:
+                continue
             else:
                 init_list.append(field.attname)
         # Retrieve all the requested fields
@@ -1174,7 +1178,11 @@ def get_cached_row(klass, row, index_start, using, max_depth=0, cur_depth=0,
 
     else:
         # Load all fields on klass
-        field_count = len(klass._meta.fields)
+        if local_only:
+            field_names = [f.attname for f in klass._meta.local_fields]
+        else:
+            field_names = [f.attname for f in klass._meta.fields]
+        field_count = len(field_names)
         fields = row[index_start : index_start + field_count]
         # If all the select_related columns are None, then the related
         # object must be non-existent - set the relation to None.
@@ -1182,7 +1190,7 @@ def get_cached_row(klass, row, index_start, using, max_depth=0, cur_depth=0,
         if fields == (None,) * field_count:
             obj = None
         else:
-            obj = klass(*fields)
+            obj = klass(**dict(zip(field_names, fields)))
 
     # If an object was retrieved, set the database state.
     if obj:
@@ -1229,7 +1237,7 @@ def get_cached_row(klass, row, index_start, using, max_depth=0, cur_depth=0,
             next = requested[f.related_query_name()]
             # Recursively retrieve the data for the related object
             cached_row = get_cached_row(model, row, index_end, using,
-                max_depth, cur_depth+1, next)
+                max_depth, cur_depth+1, next, local_only=True)
             # If the recursive descent found an object, populate the
             # descriptor caches relevant to the object
             if cached_row:
@@ -1242,7 +1250,20 @@ def get_cached_row(klass, row, index_start, using, max_depth=0, cur_depth=0,
                     # If the related object exists, populate
                     # the descriptor cache.
                     setattr(rel_obj, f.get_cache_name(), obj)
-
+                    # Now populate all the non-local field values
+                    # on the related object
+                    for rel_field,rel_model in rel_obj._meta.get_fields_with_model():
+                        if rel_model is not None:
+                            setattr(rel_obj, rel_field.attname, getattr(obj, rel_field.attname))
+                            # populate the field cache for any related object
+                            # that has already been retrieved
+                            if rel_field.rel:
+                                try:
+                                    cached_obj = getattr(obj, rel_field.get_cache_name())
+                                    setattr(rel_obj, rel_field.get_cache_name(), cached_obj)
+                                except AttributeError:
+                                    # Related object hasn't been cached yet
+                                    pass
     return obj, index_end
 
 def delete_objects(seen_objs, using):

django/db/models/sql/compiler.py

@@ -215,7 +215,7 @@ class SQLCompiler(object):
         return result
 
     def get_default_columns(self, with_aliases=False, col_aliases=None,
-            start_alias=None, opts=None, as_pairs=False):
+            start_alias=None, opts=None, as_pairs=False, local_only=False):
         """
         Computes the default columns for selecting every field in the base
         model. Will sometimes be called to pull in related models (e.g. via
@@ -240,6 +240,8 @@ class SQLCompiler(object):
         if start_alias:
             seen = {None: start_alias}
         for field, model in opts.get_fields_with_model():
+            if local_only and model is not None:
+                continue
             if start_alias:
                 try:
                     alias = seen[model]
@@ -643,7 +645,7 @@ class SQLCompiler(object):
                 )
                 used.add(alias)
                 columns, aliases = self.get_default_columns(start_alias=alias,
-                    opts=model._meta, as_pairs=True)
+                    opts=model._meta, as_pairs=True, local_only=True)
                 self.query.related_select_cols.extend(columns)
                 self.query.related_select_fields.extend(model._meta.fields)
 

tests/regressiontests/select_related_onetoone/models.py

@@ -43,8 +43,7 @@ class StatDetails(models.Model):
 
 
 class AdvancedUserStat(UserStat):
-    pass
+    karma = models.IntegerField()
-
 
 class Image(models.Model):
     name = models.CharField(max_length=100)

tests/regressiontests/select_related_onetoone/tests.py

@@ -22,7 +22,7 @@ class ReverseSelectRelatedTestCase(TestCase):
 
         user2 = User.objects.create(username="bob")
         results2 = UserStatResult.objects.create(results='moar results')
-        advstat = AdvancedUserStat.objects.create(user=user2, posts=200,
+        advstat = AdvancedUserStat.objects.create(user=user2, posts=200, karma=5,
                                                   results=results2)
         StatDetails.objects.create(base_stats=advstat, comments=250)
 
@@ -74,13 +74,16 @@ class ReverseSelectRelatedTestCase(TestCase):
         self.assertQueries(2)
 
     def test_follow_from_child_class(self):
-        stat = AdvancedUserStat.objects.select_related("statdetails").get(posts=200)
+        stat = AdvancedUserStat.objects.select_related('user', 'statdetails').get(posts=200)
         self.assertEqual(stat.statdetails.comments, 250)
+        self.assertEqual(stat.user.username, 'bob')
         self.assertQueries(1)
 
     def test_follow_inheritance(self):
-        stat = UserStat.objects.select_related('advanceduserstat').get(posts=200)
+        stat = UserStat.objects.select_related('user', 'advanceduserstat').get(posts=200)
         self.assertEqual(stat.advanceduserstat.posts, 200)
+        self.assertEqual(stat.user.username, 'bob')
+        self.assertEqual(stat.advanceduserstat.user.username, 'bob')
         self.assertQueries(1)
 
     def test_nullable_relation(self):