Re: [Qemu-devel] Switch to GIT. Why?

["M. Warner Losh" <imp@bsdimp.com>]

In message: <20090426155257.7c6dac29.mle+tools@mega-nerd.com>
            Erik de Castro Lopo <mle+tools@mega-nerd.com> writes:
: C.W. Betts wrote:
: 
: > Perhaps this has already been answered on the boards, but why was  
: > there a move to GIT?
: 
: I can't answer specifically for the Qemu case, but generally distributed
: version control systems (DVCS) like git, bzr, hg, darcs etc are better for
: distributed development than centralized systems like cvs and svn.

They work better when the number of contributors is much greater than
the number of folks with write access to the repo.  They work about
the same when the numbers are about equal (although there are benefits
for the dvcs in this case too), modulo feature differences (eg perfoce
still blows the doors off all FOSS vcs systems for its branch merging
abilities, yet it is centralized).

: Above all, dvcs' are far better at handling and merging multiple branches.
: I use svn at work, and I do realise that svn recently got much better at
: merging between branches than it was, but it is still a poor cousin to
: the others in this regard.

At the expense, at least with hg and git, that you can't do subtree
checkouts.  You also lose the strict numbering that svn was giving us,
since both git and hg compute a hash of the tree and use that as a
revision number.  Usually this isn't a big deal, but something to be
aware of if you used to checkout sub-trees to do bug bisection...

: > The main reason why I ask is because I don't have GIT installed on my  
: > system.
: 
: You're sending email using a Mac so this may be what you are
: after:
: 
:     http://code.google.com/p/git-osx-installer/
: 
: On Debian/Ubuntu based Linux systems:
: 
:    apt-get install git
: 
: On Fedora Linux:
: 
:    yum install git

On FreeBSD:

cd /usr/ports/devel/git
make all install clean

or

portupgrade -P -N git

: > Is it possible to set it up so that GIT has an SVN back-end?
: 
: Not that I know of.

I thought I saw an email go by that it was already setup...

Warner