Hi Everyone, 

Thanks for notmuch mail, it is a great program!

I am having an issue searching with --output=files and the folder prefix.

Could you please tell me if I've misunderstood something or perhaps there is 
something wrong with my setup. Details of 2 examples below:

$ notmuch --version
notmuch 0.15.2

----
1. Archive folder

Archive message #: 1356
Directory: $HOME/Mail/Gmail/[Gmail].Archive

$ notmuch count folder:Archive
1356

$ notmuch search --output=messages folder:Archive | wc -l
1356

$ notmuch search --output=files folder:Archive | wc -l
1572

I wondered why I was getting more files listed in the last example. It turns out 
some files are included from other folders. For example:

Mail/Gmail/[Gmail].Sent Mail/cur/137075610...28e65ad90fc4f:2,S

If I then do this:

$ notmuch search --output=files folder:Archive | grep Archive | wc -l
1356

I get the correct count again.

Different folders have a similar issue:

2. INBOX folder

INBOX message #: 87
Directory: $HOME/Mail/Gmail/INBOX

$ notmuch count folder:INBOX
87

$ notmuch search --output=messages folder:INBOX | wc -l
87

$ notmuch search --output=files folder:INBOX | wc -l
97

This time some messages from Archive are included:

Mail/Gmail/[Gmail].Archive/cur/137077654...d7c877e152f72dd5ddbc11f:2,S

$ notmuch search --output=files folder:INBOX | grep INBOX | wc -l
87
----

I think this illustrates the problem I'm having. Maybe I don't understand how 
the folder: prefix works? Perhaps it is my folder structure - the inclusion of 
the imap prefix [Gmail].?? It seems the search is matching the correct messages 
though, but the output of files includes messages from another folder. 

Any advice would be appreciated.

Thanks,
Nathan.