Re: CVS -> SVN -> Git

From: Michael Haggerty <mhagger@alum.mit.edu>
Date: Jul 15, 2007, 11:48 UTC
Message-ID: <469A099E.6060906@alum.mit.edu>
In-Reply-To: <7154c5c60707141623s3f70e967s226e5da29965a173@mail.gmail.com>

David Frech wrote:

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> I have a modest svn repo (about 800 commits) that contains fifteen or
> so small projects. It started life as a CVS repo, and as the projects
> grew and changed, and as I learned more about CVS, things got moved
> around. Later, when I got interested in svn (in 2005) I converted the
> repo, using cvs2svn. It got a few things wrong - mostly, that it
> thought there was one project in the repo, and created toplevel
> trunk/, branches/, and tags/ directories, and lumped everything below
> these.

I know this tangential to the main point of your post, but BTW multiproject conversions were added to cvs2svn in release 1.5.

> It took a day and half to get the svn dump parsing right (it's an
> egregiously bad format) but only a couple of hours to write the
> fast-import backend.

I'm surprised you think that; I find the svn dump format quite easy and straightforward. (Of course it assumes some Subversionisms, like easy deep directory copies, which I can imagine would be annoying in other contexts.) What don't you like about the format?

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> Having done all this, I realized that this is a good way to go.
> Separating, as Michael suggests, the "parsing" part from the "commit
> generating" part, not only makes the tools easier to write, but makes
> them more flexible. If hg or bzr had a git-like fast-import (maybe
> they do) it would take me about 35 minutes to target that instead. And
> in the process I came across some "missing features" in fast-import,
> which Shawn Pearce was able to quickly add.

Yes, fast-import is a very easy-to-write format and looks to be very well documented. I don't think that having to write output in fast-import format would be any kind of a hindrance for such a tool.

Michael