Fixed Queryset.dates() in the presence of extra-select columns.

Any extra(select=...) columns can be ignored in the SQL for dates, since we are
only interested in extracting distinct date values. We were previously
including them by accident and it was generating incorrect SQL.


git-svn-id: http://code.djangoproject.com/svn/django/trunk@9091 bcc190cf-cafb-0310-a4f2-bffc1f526a37

django/db/models/sql/subqueries.py

@@ -394,6 +394,7 @@ class DateQuery(Query):
         self.select = [select]
         self.select_fields = [None]
         self.select_related = False # See #7097.
+        self.extra_select = {}
         self.distinct = True
         self.order_by = order == 'ASC' and [1] or [-1]
 

tests/regressiontests/extra_regress/models.py

@@ -1,4 +1,5 @@
 import copy
+import datetime
 
 from django.contrib.auth.models import User
 from django.db import models
@@ -9,6 +10,7 @@ from django.utils.datastructures import SortedDict
 class RevisionableModel(models.Model):
     base = models.ForeignKey('self', null=True)
     title = models.CharField(blank=True, max_length=255)
+    when = models.DateTimeField(default=datetime.datetime.now)
 
     def __unicode__(self):
         return u"%s (%s, %s)" % (self.title, self.id, self.base.id)
@@ -31,12 +33,13 @@ class Order(models.Model):
 __test__ = {"API_TESTS": """
 # Regression tests for #7314 and #7372
 
->>> rm = RevisionableModel.objects.create(title='First Revision')
+>>> rm = RevisionableModel.objects.create(title='First Revision', when=datetime.datetime(2008, 9, 28, 10, 30, 0))
 >>> rm.pk, rm.base.pk
 (1, 1)
 
 >>> rm2 = rm.new_revision()
 >>> rm2.title = "Second Revision"
+>>> rm.when = datetime.datetime(2008, 9, 28, 14, 25, 0)
 >>> rm2.save()
 >>> print u"%s of %s" % (rm2.title, rm2.base.title)
 Second Revision of First Revision
@@ -107,4 +110,9 @@ True
 >>> User.objects.filter(pk=u.id).extra(select={'extra_field': 1}, order_by=['extra_field']).distinct()
 [<User: fred>]
 
+# When calling the dates() method on a queryset with extra selection columns,
+# we can (and should) ignore those columns. They don't change the result and
+# cause incorrect SQL to be produced otherwise.
+>>> RevisionableModel.objects.extra(select={"the_answer": 'id'}).dates('when', 'month')
+[datetime.datetime(2008, 9, 1, 0, 0)]
 """}