= Git =
[[TOC]]
Sahana Eden has decided to move from !Bzr/LaunchPad to !Git/GitHub
== Why? ==
* The current repository is huge & bloated, taking too long to download.
* Even simple changes take an age to Pull down to servers
* Web2py no longer supports !Bzr/LaunchPad, so we want to be able to maintain a common tool to work with both repositories.
* New developers are likely to be more familiar with !Git/GitHub
== How? ==
The preferred approach is to have a clean repository, in order to get the maximum benefit from the migration...although it is technically possible to [http://fearthecowboy.com/2011/04/29/converting-bazaar-repositories-to-git/ migrate the commit history]. Commit History will instead be maintained on the !LaunchPad site as an archive
=== Fork a fresh Branch ===
* Sign-up for an account on [https://github.com GitHub]
* Fork the Eden Branch: https://github.com/flavour/eden/fork_select
* Use Git to clone this down to your PC:
{{{
cd web2py/applications
git clone git@github.com:mygitusername/eden.git
}}}

=== Migrating existing Branches ===
Merge branch with trunk using normal Bzr tools

Assuming that you have already [https://github.com/flavour/eden/fork_select forked Eden Trunk], then you will need to create a new repository manually for additional branches, as you cannot [http://bitdrift.com/post/4534738938/fork-your-own-project-on-github fork your own project on GitHub]:
* https://github.com/repositories/new
{{{
cd web2py/applications
git clone git@github.com:flavour/eden.git <mybranch>2
}}}
* Move {{{.git}}} & {{{.gitignore}}} from <mybranch>2 to <mybranch>
* Delete the rest of <mybranch>2
* Edit {{{.git/config}}}:
{{{
[remote "origin"]
    fetch = +refs/heads/*:refs/remotes/origin/*
    url = git@github.com:<mygitusername>/<mybranch>.git
}}}
* Copy all the contents from <mybranch2> into <mybranch>
{{{
cd <mybranch>
git add .
git commit -am "Initial Git version of My branch"
git push -u origin master
git remote add upstream git://github.com/flavour/eden.git
}}}
=== Developer Workflow ===
We suggest adopting the [http://blog.hasmanythrough.com/2008/12/18/agile-git-and-the-story-branch-pattern Story Branch] pattern, which allows squashing commits in order to keep the main Trunk as clean as possible
{{{
cd <mybranch>
# Update your working directory with latest code from Trunk
git pull upstream master
git checkout -b <mystory>
git commit -am "My Story"
# Quick review of code (no test code left in, etc)
git diff master
# Merge latest Trunk
git checkout master
git pull
git checkout <mystory>
git rebase master
# Push to your branch on GitHub
git checkout master
git merge <mystory>
git push
# Cleanup
git branch -d <mystory>
}}}

To resolve merge conflicts, you can create the .THIS & .OTHER files using:
{{{
git show :2:file.txt > file.txt.THIS
git show :3:file.txt > file.txt.OTHER
}}}

Although on Windows this seems by default to produce UTF-16 files! ('UCS-2 Little Endian'). A script to make this process easier for Windows users is attached: [http://eden.sahanafoundation.org/attachment/wiki/DeveloperGuidelines/Git/merge.cmd merge.cmd]
=== Developer Configuration ===
{{{
git config --global user.name "Your Name"
git config --global user.email your@email.com
git config --global github.user yourgithubusername
git config --global github.token yourtoken
git config --global core.editor "'C:/Program Files (x86)/Notepad++/notepad++.exe' -multiInst -notabbar -nosession -noPlugin"
git config --global merge.tool diffmerge
git config --global diff.tool diffmerge
git config --global difftool.diffmerge.cmd 'C:/Program Files (x86)/Git/etc/wrappers/git-diff-diffmerge-wrapper.sh' "$LOCAL" "$REMOTE"
git config --global difftool.prompt false
git config --global merge.tool diffmerge
git config --global mergetool.diffmerge.cmd 'C:/Program Files (x86)/Git/etc/wrappers/git-merge-diffmerge-wrapper.sh' "$PWD/$LOCAL" "$PWD/$BASE" "$PWD/$REMOTE" "$PWD/$MERGED"
git config --global mergetool.prompt false
git config --global mergetool.trustExitCode false
git config --global mergetool.keepBackup false
}}}
==== Windows ====
Install [http://sourceforge.net/projects/console/ Console] & [http://www.sourcegear.com/diffmerge/downloads.php Diffmerge] & [http://markembling.info/2009/09/my-ideal-powershell-prompt-with-git-integration configure Powershell].
=== Developer Tools ===
{{{.gitattributes}}} runs {{{version.py}}} to update the {{{VERSION}}} file on commit

Possibly we could add a pre-commit hook to run tests, e.g. based on http://tech.yipit.com/2011/11/16/183772396/ or http://blog.penzilla.net/2011/09/git-pre-commit-hook-for-python-now-with.html

== How to get your work Merged into Trunk ==
 * Make sure your work is fully tested.
 * Tell git about any new files you've added. If you've added a new directory, you can just add the files in the directory and git will add the directory too. (Do "git help add" for a description of how to use the bzr add command.)
{{{
git add filename...
}}}
 * Commit your changes -- this records them in your local git repository. Provide a message that describes what the change is for. If it fixes a bug, include the ticket number.
{{{
git commit -a -m "Describe your change here."
}}}
 * It is really important, that the forked and the main eden repositorys are in sync here as we want to avoid merge-conflicts. To do that we need a branch of the eden master-repository:
{{{
 * Make sure that you are in the Eden directory here!
git remote add upstream https://github.com/flavour/eden.git
git fetch upstream
}}}
 * Now you have a branch of the original Eden repository. If you want to update your master-branch, you can fetch it again and merge both branches:
{{{
git fetch upstream
git merge upstream/master
}}}
 * Solve the conflicts if there were any
 * Finally commit the merged version, push it to GitHub and send a Pull-Request on the GitHub site:
{{{
git status
... add missing files ...
git commit -a -m "Some message"
git push
}}}

== Reverting to last committed code ==
If you want to throw away all uncommitted changes (i.e. '{{{bzr revert}}}'), then:
{{{
git reset --hard HEAD
}}}
== Resources ==
* Community Book: http://book.git-scm.com
* Tips & Tricks: http://gitready.com