Version control systems

[Simon Marlow]

Following lots of useful discussion and evaluation of the available DVCSs 
out there, the GHC team have made a decision: we're going to switch to git.

It came down to two things: the degree of support available, and 
flexibility of the tools (git is much happier to let you modify the history 
than Mercurial).  Speed ruled out bzr, and Windows support is less of an 
issue: git appears to work reasonably well on Windows these days.

So we need a plan for switching.  We aim to make the switch shortly before 
branching the repository for 6.10, which would mean we need to make the 
switch early September, in around 5 weeks time.

Before then, the goal is to get the infrastructure to the point where we 
can switch with minimum fuss.  We already have an up-to-date git mirror 
thanks to Thomas Schilling:

    git clone http://darcs.haskell.org/ghc.git

(notice how fast that is :-)

darcs-all will be able to work with either the git repository or the darcs 
repository (Max Bolingbroke is working on this, I believe).  We can switch 
the automatic builds over to git as soon as darcs-all is working, and as 
long as the git mirror is kept up to date (Thomas: is the mirror being 
automatically updated now?).

I'd urge people to try out the git mirror and let us know how you get on. 
We'll also work on updating the build documentation on the wiki and 
creating a page of getting-started info on using git.

Cheers,
	Simon