There are automatically updated git mirrors of Numpy (and Scipy) available:

• http://github.com/pv/numpy-svn
• http://github.com/pv/scipy-svn

You can use these to make developing contributions to Numpy and Scipy easier. An example workflow is discussed on this page.

There are also several developer's work repositories there, for example:

• http://github.com/pv/scipy-work
• http://github.com/cournape/numpy

You may also find Git's documentation useful:

• http://git-scm.com/documentation

There are also a lot of other resources to learn git on the web; this text concentrates more on using this specific SVN mirror.

Preparations

Clone the Git mirror

You need to clone the Git mirror of Scipy's SVN repository first. This needs to be done only once.

git clone git://github.com/pv/scipy-svn.git scipy.git

This will take some time, as the repository (ca. 30 MB) contains Scipy's whole history.

Then, get the SVN branch pointers. First, edit scipy.git/.git/config and change the remote "origin" section to look like this:

[remote "origin"]
	url = git://github.com/pv/scipy-svn.git
	fetch = +refs/remotes/*:refs/remotes/*
        fetch = +refs/heads/*:refs/remotes/origin/*

ie. change heads to remotes and origin to svn. Then run

git fetch

XXX: this is mildly ugly, we can investigate if it's possible to streamline this

Now you can do

git log trunk

to view the commit log of Scipy's trunk. Or, list branches and tags in SVN:

git branch -r

Initializing git-svn

This is optional, but needs to be done if you want to use git-svn to commit your changes back to SVN.

git-svn init -s http://svn.scipy.org/svn/scipy
git-svn rebase -l

This should be very fast.

Using the git clone

Create a branch

There is one rule to always remember: never work on a remote (eg. SVN) branch directly, always on a branch made from it'''

Concretely, if you want to work on the trunk

# Make a branch 'work' based on trunk, and switch to it
git checkout -b work trunk

You can list available branches with

git branch       # <- your branches
git branch -r    # <- remote branches

Edit and commit

For this point, things function as explained in the Git tutorial: http://www.kernel.org/pub/software/scm/git/docs/gittutorial.html

Commands typically needed:

git add FILES       # add new files
git commit FILES    # commit. If you don't supply files, supply -a to commit everything

Staying abreast SVN

To fetch new items from the SVN mirror, just do

git fetch

Then, you'll need to merge your changes with those in trunk. Two options: rebase or merge.

If you haven't published your changes, you can just use rebase:

git rebase trunk

If there are conflicts, it will ask you to resolve them. After all is done, your commits will lie on top of those in SVN. Note that if one of your commits exactly matches changes made in SVN, it will silently disappear in rebasing.

An alternative is merging, which does not rewrite history,

git merge trunk

XXX: but committing changes back using git-svn may be more hairy if there are merges? Also, you get duplicate commits, since SVN cannot contain merge commits

Collaboration via git

This should work similarly as in standard Git, but let's briefly mention some main points:

Publishing your branches

For example http://github.com offers free space for publishing your work on Open-source projects. It's one of the most prominent providers, so we concentrate on it for now.

For github, you can fork the scipy-svn repository via the web interface, so that you don't need to transfer a lot of data the first time. Note that you need to have a SSH private key to upload. Check the documentation

http://github.com/guides/home

for how to get started with this.

After that, tell git about your github account and the repository there

git remote add github git@github.com:pv/scipy-work.git

The address is specific to your account, so change it accordingly.

Pushing your branch there:

git push github BRANCHNAME

Viewing other people's changes

First, tell Git about someone's branch:

git remote add pauli git://github.com/pv/scipy-work.git
git fetch pauli
git remote show pauli

Switch the working tree to it:

git checkout pauli/ticket-503-special-iv-fix

Examine what was done there:

git log trunk..
git diff trunk
git show bb21c
git show 7f738

If you want to hack on it yourself, again create a branch of your own:

git checkout -b ticket-503-special-iv-fix pauli/ticket-503-special-iv-fix

Dealing with changes in SVN

XXX: todo, find out and explain what to do if you have made changes to someone's stuff, and he/she has rebased against SVN in the meantime

Dealing directly with SVN

If you configured git-svn as instructed above, you can interface directly to SVN.

Fetching items directly from SVN

You can update your repository directly from SVN. It will still stay compatible with the SVN mirror even if you do this.

git svn fetch

Committing to SVN

Commit back to the scipy svn repository with git svn dcommit:

git svn dcommit

Note that this will create one commit for each one you have in Git.

If you want to compress things to more compact form, you can use rebase

git rebase -i HASH

where HASH is a commit preceding the one, starting from which you want to compress history. This interactive rebasing allows you e.g. to edit commit messages, reorder commits (may cause conflicts), or squash several commits into a single one.

It may be wise to do create a separate branch for working on this in case you mess up.

Before actually committing, it is also a good idea to check whether you are committing where you think you are committing (with the dry run option of git svn dcommit):

git svn dcommit -n