[Dovecot] Search fails on underscores in quoted-printable

[Andreas M. Kirchwitz]

Hi folks,

currently I'm running Dovecot 1.2.1. Compiled from source on
Fedora 10 Linux 32 Bit (all patches). Clients are Pine 4.64,
Thunderbird 2.0.0.22 and Mutt 1.5.20 (using "=b" for server-side
searching).

When a message contains the text "under_score" and I let the
server search for it, Dovecot does not find it in messages
with a Content-Transfer-Encoding of "quoted-printable".

It works perfectly well with messages without Content-Transfer-Encoding.

If I replace the underscore with a space (search for "under score"),
it magically matches on "under_score" (no space but underscore).
Looks like something goes wrong with the encoding/decoding of
quoted-printable (sorry, haven't tried with base64).

Example: Dovecot does not find "under_score"

 | Date: Fri, 24 Jul 2009 02:08:45 +0200
 | From: "Andreas M. Kirchwitz" <amk at krell.zikzak.de>
 | To: "Andreas M. Kirchwitz" <amk at krell.zikzak.de>
 | MIME-Version: 1.0
 | Content-Type: text/plain; charset=iso-8859-1
 | Content-Disposition: inline
 | Content-Transfer-Encoding: quoted-printable
 | 
 | test for under_score and dovecot search (=E4=F6=FC=DF)

Example: Dovecot find's "under_score" without problems

 | Date: Fri, 24 Jul 2009 02:10:26 +0200
 | From: "Andreas M. Kirchwitz" <amk at krell.zikzak.de>
 | To: "Andreas M. Kirchwitz" <amk at krell.zikzak.de>
 | MIME-Version: 1.0
 | Content-Type: text/plain; charset=us-ascii
 | Content-Disposition: inline
 | 
 | test for under_score and dovecot search (1234)

The problem is not new to Dovecot 1.2.1 but exists in the 1.1 series
as well.

	Greetings, Andreas