Creating own hierarchies under $GITDIR/refs ?

Hi,

in the context of an ongoing discussion on the Emacs developer list of converting the Bzr repository of Emacs, one question (with different approaches) is where to put the information regarding preexisting Bazaar revision numbers and bug tracker ids: those are not present in the current Git mirror.

Putting them in the commit messages would require a full history rewrite, and if some are missed in the process, this cannot be fixed afterwards.

So I mused: refs/heads contains branches, refs/tags contains tags. The respective information would likely easily enough be stored in refs/bzr and refs/bugs and in that manner would not pollute the "ordinary" tag and branch spaces, rendering "git tag" and/or "git branch" output mostly unusable. I tested creating such a directory and entries and indeed references like bzr/39005 then worked.

However, cloning from the repository did not copy those directories and references, so without modification, this scheme would not work for cloned repositories.

Are there some measures one can take/configure in the parent repository such that (named or all) additional directories inside of $GITDIR/refs would get cloned along with the rest?

It would definitely open viable options for dealing with mirrors and/or repository migrations in general.