problem upgrading from offlineimap 6.3.4 to 6.6.1

Nicolas Sebrecht nicolas.s-dev at
Fri Mar 4 11:11:18 GMT 2016

On Fri, Mar 04, 2016 at 09:50:16AM +0100, francois at wrote:
> On Sun, Feb 28, 2016 at 07:29:02PM +0100, Nicolas Sebrecht wrote:

> > I guess this might be confusing or make bad things (including data loss)
> > if applied on mails that has moved from a folder to another one without
> > a full filename change because this might lead to UID conflicts.
> Indeed at first glance patch seems sound but this potential UID
> conflicts annoys me. Is it possible to retrieve the older FMD5 (before
> the change of using nametrans) and replace only those matching the old
> one ?

Theorically, I believe that's possible to re-introduce the old algo to
re-hash the old FMD5.

However, I'm not much worried. The conflicts would only appear in the
very edge-case when the user runs the fix while unexpected filemane
changes happened since the previous sync. I'd say this edge-case would
not worth the trouble in the code. If you worry about that, it's enough
to add a warning before fixing the hashes. Something like:

  "Ensure to dispose a proper backup of both the cache and the Maildir
  before running this fix. Be aware that if you made unexpected changes
  to filenames in the maildir (behind OfflineIMAP's back) since your
  previous sync, bad things might occur.

  Continue? (y/n)"

Either way would still be much better than the current alternatives
where users have to find the proper fix by themselves and possibly do
worse things.

Also, I may update the blog post written by Fran├žois at

if none of you intend to do it.

Nicolas Sebrecht

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