.count() not working with DateQuerySet returned from .dates()

What sort of data are you using to replicate this problem? Before I go digging too deeply, it would be nice to know how difficult it is to replicate. Are the timestamps all on the same day? Or spread over multiple days?

My data is spread over several days. 'timestamp' is a datetime field. It's easy to replicate, I looked in the class that dates "returns" and it didn't appear to have a count at all. Here's a simple test class:

class TestModel(models.Model):
    timestamp = models.DateTimeField()

I started a project, filled in settings.py with an SQLite database and added an app with this model. Here's the output from a session with "manage.py shell":

>>> from s.models import TestModel
>>> t = TestModel()
>>> from datetime import datetime
>>> t.timestamp = datetime.now()
>>> t.save()
>>> t = TestModel()
>>> from datetime import timedelta
>>> t.timestamp = datetime.now() - timedelta(1)
>>> t.save()
>>> t = TestModel()
>>> t.timestamp = datetime.now() - timedelta(1, 1)
>>> t.save()
>>> TestModel.objects.all()
[<TestModel: TestModel object>, <TestModel: TestModel object>, <TestModel: TestModel object>]
>>> TestModel.objects.count()
3
>>> TestModel.objects.dates('timestamp', 'day').count()
3
>>> TestModel.objects.dates('timestamp', 'day')
[datetime.datetime(2007, 12, 16, 0, 0), datetime.datetime(2007, 12, 17, 0, 0)]
>>> len(TestModel.objects.dates('timestamp', 'day'))
2

I'll attach the project as a tarball. It's already got the three objects created in the snippet above, so you should be able to reproduce the bug with just:

from s.models import TestModel
TestModel.objects.dates('timestamp', 'day').count()
len(TestModel.objects.dates('timestamp', 'day'))

Hope this helps.

Small test project/app

(In [6959]) queryset-refactor: Made qs.dates(...).count() work.

This involved a slight change in the SQL for .dates() which appears to be correct and passes all the tests, but may have some side-effect I don't know about.

Refs #6203.

(In [7477]) Merged the queryset-refactor branch into trunk.

This is a big internal change, but mostly backwards compatible with existing code. Also adds a couple of new features.

Fixed #245, #1050, #1656, #1801, #2076, #2091, #2150, #2253, #2306, #2400, #2430, #2482, #2496, #2676, #2737, #2874, #2902, #2939, #3037, #3141, #3288, #3440, #3592, #3739, #4088, #4260, #4289, #4306, #4358, #4464, #4510, #4858, #5012, #5020, #5261, #5295, #5321, #5324, #5325, #5555, #5707, #5796, #5817, #5987, #6018, #6074, #6088, #6154, #6177, #6180, #6203, #6658