Re: CVS -> SVN -> Git

From: Eric S. Raymond <esr@thyrsus.com>
Date: Jul 15, 2007, 01:39 UTC
Message-ID: <20070715013949.GA20850@thyrsus.com>
In-Reply-To: <46994BDF.6050803@alum.mit.edu>

Michael Haggerty <mhagger@alum.mit.edu>:

> Could you give a quick summary of the relevant differences between CVS
> and RCS files in this context?  Then I'd be happy to try to figure out
> how bad the situation still is today, and whether it can be easily improved.

I found my copy of the bug report, and I misremembered the problem slightly. It turns out to be even more relevant to this discussion than I thought.

Thread begins with <20040810031409.GA25564@thyrsus.com> on 9 Aug 2004. The thread title was "RFC -- enhancing cvs2svn to have a notion of spans of mergeable commits". Your mailing-list archive search can't seem to find it, unfortunately. I'll repost the query iseparately

> Other people have complained about having to convert from SVN to
> distributed SCMs, because the SVN model doesn't map so easily to their
> favorite.

OK.  But I think that if SVN -> X is hard, CVS -> X is going to be harder.

> You are basically suggesting that an SVN repository is the best lingua
> franca of the SCM world, which I don't believe.

Not quite. I'm suggesting it's an appropriate lingua franca for centralized VCSes with branching, e.g. everything pre-Arch.

>                                               The CVS history *does*
> have to be deformed a bit to fit into SVN, and an svn2xxx converter
> would have to undo the deformation.

Then perhaps the right thing to think about is this: how exactly does CVS history need to be deformed, and is there some way to express the lost information as conventional properties or tags?

> My idea is not to built (for example) cvs2git; rather, I'd like cvs2svn
> to be split conceptually into two tools:

Well, that makes more sense. But how would whatever the first half outputs be different from an svn dump file?

-- 
		<a href="http://www.catb.org/~esr/">Eric S. Raymond</a>