Darcs should provide an in-place upgrade-to-hashed mechanism.

Right now, the workaround is

 darcs get --hashed old tmpnew
 mv old/_darcs/prefs/defaults tmpnew/_darcs/prefs
 rm -rf old/_darcs
 mv tmpnew/_darcs old

We could also recycle optimize --modernize for this

Check out darcs optimize --pristine which is available in darcs-hs. This should
(with light adaptations) cover the pristine part of optimize --hashed. You
still need to fix the patches of course.

On Sun, Aug 30, 2009 at 18:34:21 +0000, Petr Ročkai wrote:
> Check out darcs optimize --pristine which is available in darcs-hs. This should
> (with light adaptations) cover the pristine part of optimize --hashed. You
> still need to fix the patches of course.

That's funny.  I was working on this at #hac7 and got as far as (a)
doing darcs check to watch for pristine corruption and (b) converting
the patches and inventory, but I still for the life of me couldn't
figure out how to (C) convert pristine.

TODO: (D) fix the format and misc junk (E) perhaps get rid of
old-fashioned crap.

So I'll have a look at optimize --pristine
Should this all be merged into a single
'upgrade-to-latest-hashed-format' type command?

Resolved by

Tue Sep 22 22:11:49 CEST 2009  Eric Kow <kowey@darcs.net>
  * Resolve issue1584: Provide optimize --upgrade command.
  This can be used for an inplace upgrade to the latest hashed format.
  Right now it only handles old-fashioned => hashed, but there may be
  future format changes for which this can be reused.

But have a look at issue1625