Surfing in Kansas

In my work in ReadTheDocs, we now support all of the major VCS repositories: svn, bzr, hg, and git. At this point in time we're only checking out the repos to their default branches, and then trying to trying to update them again to another revision. While writing this code I have had at least 3 different bugs that caused the repos not to be updated correctly. So I'm going to detail here the exact code that allows me to do this for each of these types of repos, hopefully so that when you or I need to do this in the future, we can at least start from here.

Let me know if any of these are wrong, because they probably are.

Git

Checking out a repo:

git clone --depth=1 <remote_url> <local_filepath>

Updating a repo:

git --git-dir=.git fetch
git --git-dir=.git reset --hard origin/master

I'm specifying the --git-dir here because my master repository is git as well, and I don't want to risk the git commands cascading up and applying to the outer repository. I'm also specifying --depth=1 so that I don't clone the entire repository, but only the latest commit. I don't need the history, so I'm doing this. As you can tell, I'm more familiar with git than the other VCS systems here.

Svn

Checking out a repo:

svn checkout <remote_url> <local_filepath>

Updating a repo:

svn revert --recursive .
svn up --accept theirs-full

I ran into problems here where I was calling revert without recursive and it wasn't doing anything! You need to do this from the top-level of the repo, and it will make sure all the state lower in the repo is reverted.

Bzr

Checking out a repo:

bzr checkout <remote_url> <local_filepath>

Updating a repo:

bzr revert
bzr up

This one is nice and easy.

Hg

Checking out a repo:

hg clone <remote_url> <local_filepath>

Updating a repo:

hg pull
hg update -C .

Again, a slightly different syntax to make sure that you're deleting all the files, and with the update command.

I hope this helps people in the future at least get to the point where they can pull down code and update it. My next task is figuring out how to support branching in all of the different repositories which is going to be fun, because they have different filesystem structures.