problem upgrading from offlineimap 6.3.4 to 6.6.1

[francois at avalenn.eu]

Package: offlineimap
Version: 6.6.1+dfsg1-1
Severity: normal

Hello,

As Marcelo Laia pointed out last week on offlineimap-project list
Debian has uploaded 6.6.1 on their repositories.

While upgrading from jessie to stretch for unrelated reasons
offlineimap was upgraded from 6.3.4 to 6.6.1 and it had a unexpected
effect in my case.

Indeed the nametrans change seems to imply a complete reupload of my
local mail on remote server which can be very long and painful even if
it doesn't lead to loss of data.

I think that the problem comes from the use of nametrans in
visiblename for Maildir folder (commit
6b2ec956cfe8e356d3ffd54eee34773deb73279f) because it lead to change
the FMD5 part of the filename.

A workaround which seems to work is to rename all filenames in
concerned Maildirs with the new calculated md5sum.

With my setup I use this dirty hack in shell :

    MYPREFIX=localprefix
    for box in $HOME/Maildir/${MYPREFIX}.* ; do
        cd $box
        oldmd5=$(pwd | sed 's!.*/!!' | tr -d '\n' | md5sum | sed 's/ *-$//')
        newmd5=$(pwd | sed "s!.*/!!;s!^${MYPREFIX}\.!!" | tr -d '\n' | md5sum | sed 's/ *-$//')
        for dir in cur new ; do
            rename -v "s/FMD5=${oldmd5}/FMD5=${newmd5}/" ${dir}/* ;
        done
    done


Note that this only works if done after the last use of offlineimap
6.3.4 and before the first use of offlineimap 6.6.1. If done at other
moments I think we risk loss of mails and duplicates of mails.

I would like a way for offlineimap to either upgrade concerned
Maildirs on the fly or to have a way to ensure that proper manual
actions are done before using it. As offlineimap is often used in
crontabs this must be done during upgrade of package.

François