problem upgrading from offlineimap 6.3.4 to 6.6.1

[francois at avalenn.eu]

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.

To be clear on my setup I did not change configuration with the
upgrade except for cert_fingerprint.
I use (and used) nametrans on both Local and Remote.

For Local : 
    folderfilter = lambda foldername: foldername.startswith("myprefix.")
    nametrans = lambda foldername: trans_local(foldername, "myprefix")

For Remote :
    nametrans = lambda foldername: trans_remote(foldername, "myprefix")


with 

    def trans_local(foldername, prefix):
        if foldername.startswith(prefix):
            return foldername.replace(prefix+".","",1)
        else:
            #raise AssertionError("config of nametrans with prefix '"+prefix+"' is not good")
            return "notfound_"+prefix+"_"+foldername
    
    def trans_remote(foldername, prefix):
       return prefix+"."+foldername


> > 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.

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'd be happy to apply a patch introducing the migrating script you
> provided (something in ./contrib) in order to help other users, most
> likely users of Debian.
> 
> Any blog post to offlineimap.org would be welcome, too. Your mail is
> good enough to be more widely spread in the news. ,-)

Unfortunately I don't want to take the time to formalize this in blog
post or patch. That said, feel free to reuse any content of my mails.

François.