This patch fixes the 'Deleted first duplicate file does not stop
notmuch show from working' test.
If a message to be shown has several duplicated files, and for some
reason the first file in the list is not available anymore, notmuch
will exit with an error.
This is clearly a problem in the database, but we are not going to let
this problem be a show-stopper. Let's walk through the list, and show
the first existing file.
Signed-off-by: Yuri Volchkov <yuri.volchkov@gmail.com>
The corresponding xapian document just gets more terms added to it,
but this doesn't seem to break anything. Values on the other hand get
overwritten, which is a bit annoying, but arguably it is not worse to
take the values (from, subject, date) from the last file indexed
rather than the first.
There are many other problems that could be tested, but these ones we
have some hope of fixing because it doesn't require UI changes, just
indexing changes.
