Re: [RFC] Hidden refs

On Wed, Oct 13, 2010 at 11:22:11AM -0400, Marc Branchaud wrote:

We want to have our build system record, in our repo, which commits
correspond to which builds.

Nominally, this is a job for tags.  But we don't want to have to look at
these tags all the time.  We particularly just want to tag the repo when we
make an actual release -- tags are a Big Deal for us.

Notes are an option, though they feel a bit heavy for this application.  And
although we can store the build notes in their own refspace, it would (I
believe) be a little clunky to make commands like checkout and log work with
the commits that were noted by the build system.

Keep in mind that notes and tags are basically inverses as far as
efficient lookup goes. If you want to map a build name or number to a
commit, you would use a ref which points to a commit. But if you want to
map a commit sha1 to a build number, you would use notes.

It struck me that it would be neat to have hidden refs in the refs/
directory.  I experimented a bit with a "refs/.builds" directory:

* "git update-ref refs/.builds/One" fails with "Cannot lock the
  ref 'refs/.builds/One'."  So I created a ref the regular way
  (refs/blah/One) and copied the "One" file into refs/.builds/.

Yeah, I believe "." at the front of a directory component is explicitly
forbidden by check_ref_format. I don't recall whether there was a
specific rationale, or whether it was simply a can of worms we didn't
want to explore.

...

Look like it blames to 03feddd (git-check-ref-format: reject funny ref
names., 2005-10-13).  This looks like the relevant thread:

  http://article.gmane.org/gmane.comp.version-control.git/9874

but I didn't read through it carefully.

-Peff