Always use git-svn with --prefix

TLDR: I've recently been forced back into using git-svn, and while I was at it, I noticed that git-svn generally behaves a lot better when it is initialized using the --prefix option.

Frankly, I can't see any reason why you would ever want to use git-svn without --prefix. It even added some major simplifications to my old git-svn mirror setup.

Update: Some of the advantages of this solution will disappear in newer versions of Git.

For example, make a standard-layout svn clone:

$ git svn clone -s https://svn.company.com/repos/project-foo/

You'll get this .git/config:

[svn-remote "svn"]
url = https://svn.company.com/repos/
fetch = project-foo/trunk:refs/remotes/trunk
branches = project-foo/branches/*:refs/remotes/*
tags = project-foo/tags/*:refs/remotes/tags/*

And the remote branches looks like this (git branch -a):
remotes/trunk
remotes/feat-bar

(Compared to regular remote branches, they look very odd because there is no remote name in between there.)

Now, let's say you want to work on the feat-bar branch, so you attempt to create a tracking branch feat-bar that will track remotes/feat-bar:

$ git checkout feat-bar #short hand form, usually works.
> You are in 'detached HEAD' state. #no branch created

$ git checkout remotes/feat-bar #more explicit maybe?
> You are in 'detached HEAD' state. #duh

$ git checkout -t remotes/feat-bar #even more?
> fatal: Missing branch name; try -b

$ git checkout -tb remotes/feat-bar
> Branch remotes/feat-bar set up to track local branch master.

A local branch called remotes/feat-bar?? Well, that's not what I wanted.. So I end up doing it the good old-fashioned way:

$ git checkout -tb feat-bar remotes/feat-bar

That works, and I am up and rolling, but I now get this warning with every checkout or rebase:

warning: refname 'feat-bar' is ambiguous.

This is because we have two separate branches, but Git somehow interprets them has having the same name:

feat-bar
remotes/feat-bar

Enter the --prefix

So, let's see what happens when I create the svn clone using a --prefix=mirror/ instead. Here's the config:

[svn-remote "svn"]
url = https://svn.company.com/repos/
fetch = project-foo/trunk:refs/remotes/mirror/trunk
branches = project-foo/branches/*:refs/remotes/mirror/*
tags = project-foo/tags/*:refs/remotes/mirror/tags/*

Here's what my remote branches look like now:
remotes/mirror/trunk
remotes/mirror/feat-bar

Let's create the tracking branch:

$ git checkout feat-bar
> Branch feat-bar set up to track remote branch feat-bar from mirror.

Voila, worked on the first try. And no more warnings about ambiguous refnames!

I think this is so useful that I've asked the git-devs why they don't make this default behavior in git-svn, but haven't gotten any reactions so far.

Update: There is a reaction now.

Comments

Open source CMS evaluations

I have now seen three more or less serious open source CMS reviews. First guy to hit the field was Matt Raible ( 1 2 3 4 ), ending up with Drupal , Joomla , Magnolia , OpenCms and MeshCMS being runner-ups. Then there is OpenAdvantage that tries out a handful ( Drupal , Exponent CMS , Lenya , Mambo , and Silva ), including Plone which they use for their own site (funny/annoying that the entire site has no RSS-feeds, nor is it possible to comment on the articles), following Matt's approach by exluding many CMS that seem not to fit the criteria. It is somewhat strange that OpenAdvantage cuts away Magnolia because it "Requires J2EE server; difficult to install and configure; more of a framework than CMS", and proceed to include Apache Lenya in the full evaluation. Magnolia does not require a J2EE server. It runs on Tomcat just like Lenya does (maybe it's an idea to bundle Magnolia with Jetty to make it seem more lightweight). I'm still sure that OpenAdvant

Encrypting and Decrypting with Spring

I was recently working with protecting some sensitive data in a typical Java application with a database underneath. We convert the data on its way out of the application using Spring Security Crypto Utilities . It "was decided" that we'd be doing AES with a key-length of 256 , and this just happens to be the kind of encryption Spring crypto does out of the box. Sweet! The big aber is that whatever JRE is running the application has to be patched with Oracle's JCE in order to do 256 bits. It's a fascinating story , the short version being that U.S. companies are restricted from exporting various encryption algorithms to certain countries, and some countries are restricted from importing them. Once I had patched my JRE with the JCE, I found it fascinating how straight forward it was to encrypt and decrypt using the Spring Encryptors. So just for fun at the weekend, I threw together a little desktop app that will encrypt and decrypt stuff for the given password

What I've Learned After a Month of Podcasting

So, it's been about a month since I launched GitMinutes , and wow, it's been a fun ride. I have gotten a lot of feedback, and a lot more downloads/listeners than I had expected! Judging the numbers is hard, but a generous estimate is that somewhere around 2000-3000 have listened to the podcast, and about 500-1000 regularly download. Considering that only a percentage of my target audience actively listen to podcasts, these are some pretty good numbers. I've heard that 10% of the general population in the western world regularly listen to podcasts (probably a bit higher percentage among Git users), so I like to think I've reached a big chunk of the Git pros out there. GitMinutes has gathered 110 followers on Twitter, and 63, erm.. circlers on Google+, and it has received 117 +'es! And it's been flattr'ed twice :) Here are some of the things I learned during this last month: Conceptually.. Starting my own sandbox podcast for trying out everythin

Git tools for keeping patches on top of moving upstreams

At work, we maintain patches for some pretty large open source repositories that regularly release new versions, forcing us to update our patches to match. So far, we've been using basic Git operations to transplant our modifications from one major version of the upstream to the next. Every time we make such a transplant, we simply squash together the modifications we made in the previous version, and land it as one big commit into the next version. Those who are used to very stringent keeping of Git history may wrinkle their nose at this, but it is a pragmatic choice. Maintaining modifications on top of the rapidly changing upstream is a lot of work, and so far we haven't had the opportunity to figure out a more clever way to do it. Nor have we really suffered any consequences of not having an easy to read history of our modifications - it's a relatively small amount of patches, after all. With a recent boost in team size, we may have that opportunity. Also the need for be

Managing dot-files with vcsh and myrepos

Say I want to get my dot-files out on a new computer. Here's what I do: # install vcsh & myrepos via apt/brew/etc vcsh clone https://github.com/tfnico/config-mr.git mr mr update Done! All dot-files are ready to use and in place. No deploy command, no linking up symlinks to the files . No checking/out in my entire home directory as a Git repository. Yet, all my dot-files are neatly kept in fine-grained repositories, and any changes I make are immediately ready to be committed: config-atom.git -> ~/.atom/* config-mr.git -> ~/.mrconfig -> ~/.config/mr/* config-tmuxinator.git -> ~/.tmuxinator/* config-vim.git -> ~/.vimrc -> ~/.vim/* config-bin.git -> ~/bin/* config-git.git -> ~/.gitconfig config-tmux.git -> ~/.tmux.conf config-zsh.git -> ~/.zshrc How can this be? The key here is to use vcsh to keep track of your dot-files, and its partner myrepos/mr for o