[Dovecot] search and UTF-8 normalization forms (NFD)

[Timo Sirainen]

On 25.4.2013, at 16.39, Lutz Preßler <Lutz.Pressler at SerNet.DE> wrote:

> on a system with dovecot 2.2 I've got a mailbox containing multiple mails
> from a person called Krüger, but From: header encoded differently.
> Some are encoded in UTF-8 normalization form decomposed (as used by Mac OSX),
> that is u and umlaut accent as sperate combined codepoints
> instead of one ü:
> 
>  From: =?utf-8?Q?replaced_Kru=CC=88ger?= <krueger at some.domain>
> 
> Searching within roundcube webmail for "krüger" as sender
> missis this mails.
> 
> Roundcube sends (dovecot rawlog):
> A0003 UID THREAD REFS UTF-8 ALL HEADER FROM {7+}krüger
> 
> Is this supposed to work? Haven't done any more debugging
> (other search variants) or read RFCs. As a user I would expect
> Unicode equivalence rules be applied (see 
> http://en.wikipedia.org/wiki/Unicode_equivalence)

IMAP requires using i;unicode-casemap by default, as specified by RFC 5051. Then again, others could be supported as well, and it's not really a requirement that the search can't handle more flexible searches.. Anyway, that's what Dovecot currently has implemented, and I guess it doesn't do what you want it to do. But there is a partial solution for this:

http://dovecot.org/patches/2.1/icu-1.2.tar.gz

It probably does what you want, but it only works with fts-lucene.