Re: Three issues from a Subversion-to-git migration

From: Eric Raymond <esr@thyrsus.com>
Date: Mar 29, 2010, 10:26 UTC
Message-ID: <20100329102656.GA10925@thyrsus.com>
In-Reply-To: <201003291132.53415.trast@student.ethz.ch>

Thomas Rast <trast@student.ethz.ch>:

Show 6 quoted lines

> I suppose I was never bothered by the lack of automatic tagging
> because I rarely found a git-svn import to be immediately fit for
> publishing.  Usually it took some grafting and other filtering to
> bring the history into shape anyway.  Maybe now that the svn:mergeinfo
> support obviates the need for grafting, it's worth thinking about the
> rest.

Can't argue your first point at all, because my only large migration so far did in fact need filtering - to fix up artifacts from the Emacs VC front end that were fossilized in the Subversion history. And that was all my own fault; I was the original author of VC back in the early 1990s, and should have rewritten it to be changeset-aware years sooner than I did. Alas, I was kind of busy being Mr. Famous Geek for about a decade in there, and the VC rewrite was one of several projects that got seriously sidetracked. I finally got it done in 2008-2009, and git is one of the backend systems that benefits from that.

Still. Even conceding that point, built-in support to further reduce the amount of hand-work required in SVN conversion would be no bad thing. Tag conversion was unequivocally the biggest pain in the ass when I migrated GPSD; I'm not claiming that will always be true, but I do think it's the largest pain that could be *reliably mechanized away*. That makes it a logical target.

One of the reasons this is still on my mind after the GPSD migration is Battle For Wesnoth <http://www.wesnoth.org/>. I'm one of the senior devs on that project, and it is becoming clear to all that we have reached Subversion's limits there. I'm the project's tools and toolsmithing expert, and I've pretty much got the other devs convinced to switch to a DVCS when we can screw up our courage to move to a forge that supports one.

This means I'm probably going to be the guy on the spot doing yet another big ugly conversion away from SVN sometime within the next year. The state of conversion tools at that time might end up determining whether Wesnoth goes with git or Mercurial.

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