Subject: Re: Git/Mercurial interoperability (and what about bzr?)

From: Florian Weimer <[email-masked]>
Date: Sat, 01 Nov 2008 11:44:21 +0100

* Jakub Narebski:

> Florian Weimer <[email-masked]> writes:
>> * Theodore Tso:
>> 
>> > In the past I've looked at the possibility of creating a
>> > bi-directional, incremental gateway between hg and git repositories.
>> > The main thing which makes this difficult is that hg stores tags
>> > in-band inside the change-controlled .hgtags file.  This means that if
>> > you cut a release, tag it, and then create a commit to further modify
>> > the repository, the new commit is descended from the tag commit,
>> > whereas in git, the tag is a "bookmark" --- perhaps signed via GPG,
>> > but not part of the revision history.
>> 
>> Couldn't you just keep the .hgtags file and have everyone interested
>> in the tags use special scripts?
>> 
>> (Admittedly, I'm horribly totally by Git's behavior in this area.  I
>> haven't figured out yet under what circumstances tags are pushed and
>> pulled, so I'm not totally opposed to the Mercurial model. 8-/)
>
> I think you don't understand the issue here.

Probably yes.

> Do you agree that global tags should be both non-versioned and
> trasferable?

Yes, I do.  In case of Git, I've got trouble with understanding how to
actually implement the "transferable" part with Git.  The Mercurial
way is easier to understand, but it means that tags may need some sort
of "tag at this revision" qualifier to disambiguate, which is rather
problematic.

> Now Mercurial has chosen to use in-tree '.hgtags' file to have global
> tags transferable.  Never mind the fact that it had to treat this file
> in special way to have it non-versioned

Oops, thought this file was versioned.  Things like

  <http://tycoon.hpl.hp.com/changeset/932:931d181e9f58/.hgtags>

suggest it was at some point.