Hmm, I'm getting the same results from the python implementation.

On Mon, 21 Mar 2011 09:32:52 -0700, Jameson Rollins <jrollins@finestructure.net> wrote:
> Any suggestions about how we might go about debugging this?

One thing to try would be to run it step by step in an interactive session. I.e.,

>>> import notmuch as nm
>>> db = nm.Database("/where/ever/it/is")
>>> qry = nm.Query(db, "folder:sent")

Then, two things to look at. What's the output of

>>> qry.count_messages()

and what's the output of 

>>> len(qry.search_messages())

If you're still getting weird results on both, try dumping the search
results into a list

>>> msgs = [m for m in qry.search_messages()]

and take a look at them. Anything special about those messages?

Best,
Jesse