Using Git to manage your Emacs changes

[John Wiegley <jwiegley@gmail.com>]

If anyone here is like me and can't stand Bzr's interface/lack-of-speed due to comfort with Git, there is a *somewhat* more palatable solution:

 1. Install git-bzr (http://github.com/pieter/git-bzr).  Make sure it works by
    testing on some very small project from someplace.

 2. Do a bzr checkout of Emacs.  DO NOT use git-bzr to directly checkout the
    Emacs tree.  It will take days and days and download over 20G of data.

 3. Using git-bzr, point it at your local bzr checkout so it can do a fully local
    translation of the Bzr commits to Git commits.  This will take several hours,
    but not hog network bandwidth.

 4. When done, you can fetch Bzr changes into your tree with:

      git bzr fetch upstream

 5. Now here's the tricky part.  Move your .git directory from your git-bzr checkout
    over into your Bzr working tree.  Yes, we want Bzr and Git to manage the same
    tree.  You should be wearing your Depends; this is not for the faint of heart.

 6. Create a 'master' branch to queue your Git commits.  You can make topics branches
    off the branch, just never modify the upstream branch directly.

       git checkout -b master upstream

 7. Sadly, git-bzr is sufficiently broken that you will not be able to push your
    changes with "git bzr push upstream", as the docs indicate.  Instead, we have
    to use "git format-patch" and then turn each patch into a Bzr commit manually,
    which get pushed with "bzr push".  Once pushed, "git bzr pull upstream" reflects
    that new commit back in Git:

      ./apply.sh upstream     # apply commits using script below; stash if needed
      bzr push
      git bzr fetch upstream
      git rebase upstream     # git stash pop afterwards if needed

 8. I expect a blank line after my initial commit description.  If you don't do this,
    remove the "| tail +2" from the apply script.  It would seems that using a blank
    line is standard in the Git community, but not using it in standard for the Emacs
    tree.

I know, it's quite ugly, but using Bazaar has proven even less desirable.

John

#!/bin/bash

git checkout ${1:-upstream}
git format-patch ..master

for i in [0-9]*.patch; do
        echo Applying $i

        patch -p1 < $i

        grep ^Subject: $i | sed 's/^Subject: \[PATCH\] //' > /tmp/msg.$$

        perl -ne 'print if /^$/ .. /^---/;' $i | \
          perl -ne 'print unless /^---/ .. eof()' | \
          tail +2 >> /tmp/msg.$$

        bzr commit -F /tmp/msg.$$

        rm -f /tmp/msg.$$
done

git reset --hard HEAD
git checkout master
rm -f [0-9]*.patch