= Application for Google Summer of Code 2008

== Title/Summary

Make git-merge Builtin

== Organization

Git Development Community

== Abstract

It generally has been found that the C version of a tool is more
portable and easier to maintain across systems, not to mention faster.

A lot of scripts have been converted already, but "merge" is the big remaining chunk.

I want to replace git-merge with C versions.

== Detailed Description

=== Project Goals

The goal would be to rewrite git-merge, so that it would be more portable and easier to maintain.

Measuring the success of failure of the project would be (I think)
fairly easy:

I don't know if additional tests are required before touching git-merge, if yes then I would write them first. Then the success would be if the git-merge.sh shell-script would be a builtin and all the tests would pass as well. Additionally the code would be merged to git.git as well.

Failure would be: the code not merged, or even git-merge would not be rewritten.

Description in more detail:

1) I should learn a bit more about git merge, at the moment I have no idea for example what git-merge-stupid does, and internally I don't
know how the git-merge works.

2) Once I understand how the current code works, I want to see if I need to write additional tests, to help testing when I rewrite code in C.

3) I need to learn the git C API, and I need to understand the internal structures git uses.

4) I need to rewrite git-merge itself in C. All tests should pass, then I should ask the mentor's opinion if the code is basically OK, so that I can continue with the strategies.

5) Optionally, if I have time, I would convert each strategy which is not yet a builtin: If I count correctly, then these are:

git-merge-octopus
git-merge-one-file
git-merge-resolve
git-merge-stupid

Basically this is what I would plan.

=== Interfaces

I think I'll have to use the git API, and maybe I'll have to improve it, I don't know too much about this yet.

The parts what I would like to change are: git-merge-octopus.sh,
git-merge-resolve.sh, git-merge.sh, git-merge-one-file.sh and
git-merge-stupid.sh. But just git-merge.sh, first.

=== About Me

A have a page with links to patches I contributed to other FOSS
projects:

http://vmiklos.hu/portfolio/

Mostly minor code and/or documentation fixes. I contributed a few more
complex patches to the pacman package manager, the bitlbee IM gateway,
MPlayer, and tailor.

I'm generally a bash/C/python guy. I know some perl/Java/PHP as well. I
have used CVS/SVN. I used darcs for my projects for a long time and I
use git for my projects for about a half year. These are relatively
small projects, at last I think the git one is bigger. I used email
and/or IRC for communication when I contributed.

About Git experience: I started to use git for about half year ago and
(as a user) I think I know a lot about it, as I use to read the mailing
list and I'm hanging around on #git, so that I can learn from other
people who know Git better than me.

I contributed some trivial patches and some documentation improvements,
but I'm not familiar with the internal C API.

Here is a list of patches I contributed:

http://git.kernel.org/?p=git%2Fgit.git&a=search&s=vmiklos

=== Link to Further Information

http://git.or.cz/gitwiki/SoC2008Ideas#head-c69d9395d7b1c5fc6f9cc13f0ce9839e910108cb

== Additional resources

- https://github.com/vmiklos/gsoc2008[gitweb]
- https://github.com/vmiklos/gsoc2008/downloads[patches tarball]
- link:gsoc-2k8.txt[application source]

== References

- http://article.gmane.org/gmane.comp.version-control.git/88784[GSoC
  podcast 18: Git] (http://code.google.com/p/google-developer-podcast/downloads/detail?name=gsocpodcast018.ogg&can=1&q=code[ogg])
- http://google-opensource.blogspot.com/2008/08/git-and-google-summer-of-code.html[Git
  and Google Summer of Code]