[Lightning] Switching to git

[Paolo Bonzini]

I converted GNU lightning's Arch repository to git.  All development 
after the 3.0 release will be available only through git and through the 
new git-cvs gateway (see later).  The Arch repositories 
address@hidden and address@hidden will be available but 
undocumented (so that they are slowly blurred away by time) and will not 
be up-to-date anymore.  I've added cacherevs of the last revisions to 
help people who find them by mistake, but that's as much maintainance as 
I'm willing to do.

It is recommended that you access the repository with git, of course; 
GNU Smalltalk's Git repository can be accessed through HTTP as well as 
through the faster Git protocol.  Either of the following commands will 
clone GNU Smalltalk's repository on your machine:

  git clone git://git.sv.gnu.org/lightning.git
  git clone http://git.sv.gnu.org/r/lightning.git

Cloning automatically creates a branch for your work, called master.
After cloning the repository, "git pull" will be enough to update the 
current branch with any new patch available upstream (i.e. from me).

You can also browse the Git repository within a web browser.  Unlike 
Arch, this is *fast* (well everything is faster than with Arch).  You 
may also view the complete histories of any file in the repository as 
well as differences among two versions.  Gitweb also allows you to get 
the latest source code as a tarball, like this:

>   wget -O lightning-latest.tar.gz \
>     'http://git.savannah.gnu.org/gitweb/?p=lightning.git;a=snapshot;h=master'


As with Arch, by setting up your own public repositories for GNU 
lightning branches, you will facilitate integration of your code into 
the main distribution.  You can find some info at 
http://www.gnome.org/~federico/misc/git-cheat-sheet.txt.

You can prepare a patch "the old way" just by doing a single commit in 
your master branch).  For GNU lightning it should be enough most of the 
time: just send out the URL for the branch and the sha1 identifier for 
the commit (you get it from "git log", the first 8-10 characters are 
enough) and I'll cherry-pick it.  Of course, attach the patch in the 
e-mail too for simplicity.  You can view the diff for a commit 01234ABCD 
(that's the beginning of the SHA1 checksum) with something like

  git diff 01234ABCD{^,}

For more complicated work, you can also set up a "topic branch".   Here 
you can use "git rebase <BRANCH>" (where <BRANCH> will be usually 
"master", "origin/master" or "origin/stable-VERSION") to reapply your 
patches on top of a new branch.  This is the same as "tla update", 
except that it works also if you committed something on the branch. 
Alternatively, you can use "git merge <BRANCH>" which is the same as 
"tla replay".

In both cases, use "git merge --squash <TOPIC-BRANCH>" while you're on 
the master branch to turn the topic branch into a single commit to be 
sent out the same way.


The "git rebase" example will have shown you that unlike Arch, git is 
quite happy to rewrite history unless you've already pushed upstream. 
In "topic branches" of course you are more free, because you probably 
won't push them until you're done with them.  Interesting commands to do 
so include:

"oh no, I forgot the ChangeLog"
git commit --amend

"oh no, I forgot --amend"
"the fix is a one-liner, but I committed the buggy patch two weeks ago"
git rebase --interactive HEAD^^^^


There *is* one thing you'll miss switching from Arch to git, namely "tla 
missing".  Everything else will be sweet.


Anonymous CVS access
====================

Alternatively, a CVS repository can be checked out through anonymous CVS 
with one the following commands (again, respectively for the stable and 
development branches).

  cvs -d :pserver:address@hidden:/lightning.git \
    co -d lightning HEAD

When you update from within the checked out directory you do not need 
the -d options anymore:

  cvs update

Paolo