Fixed #7813 -- Allow pickling of Query classes that use select_related().

Based on a patch from Justin Bronn.

The test in this patch most likely breaks on Oracle. That's another issue.


git-svn-id: http://code.djangoproject.com/svn/django/trunk@8053 bcc190cf-cafb-0310-a4f2-bffc1f526a37

django/db/models/sql/query.py

@@ -106,6 +106,8 @@ class Query(object):
         Pickling support.
         """
         obj_dict = self.__dict__.copy()
+        obj_dict['related_select_fields'] = []
+        obj_dict['related_select_cols'] = []
         del obj_dict['connection']
         return obj_dict
 

tests/regressiontests/queries/models.py

@@ -785,6 +785,15 @@ Bug #7204, #7506 -- make sure querysets with related fields can be pickled. If
 this doesn't crash, it's a Good Thing.
 >>> out = pickle.dumps(Item.objects.all())
 
+We should also be able to pickle things that use select_related(). The only
+tricky thing here is to ensure that we do the related selections properly after
+unpickling.
+>>> qs = Item.objects.select_related()
+>>> query = qs.query.as_sql()[0]
+>>> query2 = pickle.loads(pickle.dumps(qs.query))
+>>> query2.as_sql()[0] == query
+True
+
 Bug #7277
 >>> ann1 = Annotation.objects.create(name='a1', tag=t1)
 >>> ann1.notes.add(n1)