problem upgrading from offlineimap 6.3.4 to 6.6.1

[Ilias Tsitsimpis]

Control: tags -1 + patch

Hi François, Nicolas,

On Fri, Jan 22, 2016 at 03:03PM, francois at avalenn.eu wrote:
> On Wed, Jan 20, 2016 at 05:44:24PM +0100, Nicolas Sebrecht wrote:
> > On Wed, Jan 20, 2016 at 01:56:24PM +0100, francois at avalenn.eu wrote:
>  
> > > 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.
> > 
> > Looks sensible. This is a change introduced in the late 2011 and I don't
> > remember everything from this time. I don't recall having to either
> > use/provide any script for updates nor having the troubles you get.

Thanks for describing the problem in detail.

I, too, believe that this is a regression introduced by the above
commit. Since OfflineIMAP on Debian stable is at version 6.3.4, more
people are going to upgrade and face the above bug. Thus, I am
interested in finding an easy way to resolve this.

> > > 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.
> > 
> > I wonder if the big step foward from v6.3.4 to 6.6.1 (more than 4 years
> > of development) could be the cause. Since it's a long time between
> > releases, I wonder if temporary code to help moving forward could have
> > been introduced and then removed within this gap.

I couldn't find such a code in the history. It seems weird that nobody
complained so far.

> Indeed it is possible.
> 
> I think that a workaround should be included in Debian packaging in
> order for the upgrade to be the best experience possible. This
> workaround could be a simple flag blocking any run of offlineimap and
> this flag to be cleared by the user after reading the NEWS file.

I have created a patch that hopefully will help here[1]. My plan is to
include this to the next OfflineIMAP version in Debian, and state at the
NEWS file that everyone who is upgrading from v6.3.4 should run

    $ offlineimap --verify-fmd5 || offlineimap --fix-fmd5

before the first use of the newer version.

Could you review this, and/or verify that this is working correctly?

@nicolas: Do you believe this should be included in the mainline
OfflineIMAP repository (i.e., do you believe this has any other use
other than upgrading from v6.3.4)?

Cheers,
Ilias

[1] https://github.com/iliastsi/offlineimap/commit/8d07ec308e83665