git-svn: Use prefix by default?

[Thomas Ferris Nicolaisen <tfnico@gmail.com>]

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.

For example, I make a standard-layout svn clone:

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

.. and end up with this .gitconfig:

[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 my remote branches looks like this:
    remotes/trunk
    remotes/feat-bar

Now, let's say I want to work on the feat-bar branch, so I attempt to
create a tracking branch by the same name:

$ git checkout feat-bar  # will detach head
$ git checkout remotes/feat-bar  # will detach head
$ git checkout -t remotes/feat-bar # fatal: Missing branch name; try -b
$ git checkout -tb remotes/feat-bar # Branch remotes/feat-bar set up
to track local branch master.

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 # works

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

     warning: refname 'feat-bar' is ambiguous.

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 are my remote branches:
     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.

So now my question is: If using a prefix is so healthy for git's
branch tracking conventions, why doesn't git-svn default to use some
prefix like 'origin' or something when initializing a git svn clone?

The examples were made using 1.8.1.2 on OSX by the way.