Subject: Re: Branch names with slashes

From: Neal Kreitzinger <[email-masked]>
Date: Thu, 15 Dec 2011 14:40:53 -0600

On 12/14/2011 4:17 AM, Leonardo Kim wrote:
> Branch names can contain slashes, so we can use 'development/foo' as
> a branch name. If I choose 'development' as a branch name, it doesn't
> work. There is a directory named development at '.git/refs/heads'
> directory. So we cannot create a file named development for
> 'refs/heads/development'.
>
> An error message may occurs like below. Unfortunately, It is not of
> help to me. 'error: 'refs/heads/development/foo' exists; cannot
> create 'refs/heads/development'.
>
> I think that dealing with a file system and an error message above is
> not sufficient for a novice like me. I hope that it should be
> improved.
>
FYI, We also use slashes in our branchnames to leverage some of the 
benefits of a path-like namespace like pattern matching and the logical
expression of hierarchies using descriptive compound names. (We use git 
1.7.1 on linux.) Here's something to keep in mind: You have to plan 
(think ahead) for your naming conventions so that the namespaces will 
maintain uniqueness at a peer level over time that cannot be confused as 
subdirs under .git/refs/heads. For example:

branchnames:
/mysystem/generic
/mysystem/generic/project1

will not work because /mysystem/generic appears to be a parent dir to
/mysystem/generic/project1 under .git/refs/heads.  The solution is:

/mysystem/generic/base
/mysystem/generic/project1

these branches can coexist because they are unique without one appearing
to be a parent dir of the other.  IOW, their namespaces are peers in
their entirety. To carry the example a little further,

/mysystem/generic/project1/part2
will not work because once again it appears to be a subdir of an 
existing branchname (ref).  However,
/mysystem/generic/project1-part2
will work.

I think the reason for this is that if you look at .git/refs/heads you
will see that these slash delimited branch names are actually stored as
subdirs in the filesystem sense.  Therefore, git will get confused and
error out as it tries to find branchnames that are not entirely unique
by their full path namespace under .git/refs/heads because a branch
namespace that is a prefix (in the filesystem sense) of another branch 
name would occupy the same path under .git/refs/heads without being 
distinguishable as unique, and vice versa.

Hope this helps. (Maybe someone else will find a clearer way to explain
this.)

v/r,
neal