On Fri, 20 Feb 2015, Matthew Lear <matt@bubblegen.co.uk> wrote:
> A couple of others things have surprised me, though. Using the date search
> option, such as date:"today" or date:"yesterday", hasn't quite thrown up
> what I expected. Searching with date:"today" shows up no results (which I
> know is wrong) and searching with date:"yesterday" shows up a handful of
> emails all from the same person, in different threads which all arrived on
> a day in May 2014... Got to be a bug there somewhere :-D

This is a known limitation in the date: prefix queries. You have to
specify it as a range, for example date:today..today (from the beginning
of today until the end of today). If the underlying Xapian search engine
is not given a range expression (with the "..") it searches for the
words "date today" without punctuation, matching whatever it matches,
and notmuch does not even get an error for it.

HTH,
Jani.