Re: [PATCH 1/8] Documentation/notes: document format of notes trees

On Sat, May 08, 2010 at 10:19:35PM -0500, Jonathan Nieder wrote:

How well does ‘git notes’ handle notes trees without a commit
currently?  I remembered some rumor about a commitless mode in which
the only history is the reflog, but I am not sure how much of that is
implemented yet and I did not check.

If it was only groundless rumor (read: I made it up), then the last
paragraph of the discussion should be removed.

My original textconv caching implementation used commitless notes. The
new version uses commits, but keeps the history truncated. As far as I
know, you can manipulate the latter with git-notes, but I haven't tried
much (adding a new note should make a history graph with length 2, which
will then get re-truncated the next time we add something to the cache
automatically). But certainly "list", "show", and "prune" should work,
which are the ones I would expect to be useful for such a cache.

+It is also permitted for a notes ref to point directly to a tree
+object, in which case the history of the notes can be read with
+`git log -p -g <refname>`.

You would also use this to see the history of cache notes. They have
commits, but the only ancestry is in the reflog. So perhaps:

  Some notes refs may be "history-less", either because they point
  directly to a tree instead of a commit, or because their commits are
  truncated (the notes generated by textconv caching are an example of
  the latter). To see the local history of these refs, view the reflog
  with `git log -g <refname>`.

-Peff