Re: Git Notes idea.

From: Jeff King <peff@peff.net>
Date: Dec 17, 2008, 09:45 UTC
Message-ID: <20081217094528.GA18492@coredump.intra.peff.net>
In-Reply-To: <alpine.DEB.1.00.0812170003540.14632@racer>

On Wed, Dec 17, 2008 at 12:48:02AM +0100, Johannes Schindelin wrote:

> > Perhaps I am missing something, how is it a linear search?
> 
> Yes, you are missing what I wrote in the original thread: tree objects 
> must be read in a forward direction, one by one.

Thanks, that was a nice writeup of what was discussed at the GitTogether.

> Peff's very cute idea was to decouple that process from the per-commit 
> procedure, and basically make it a one-time cost (per Git call, and only 
> when notes were asked for).

To be fair, it was not my cute idea, but somebody else's (I think David Reiss). I just coded it quickly because somebody was talking about iPhones or something. :)

> To the contrary.  When I rebase, the tree _does_ change, otherwise I
> would have rebased onto something that had the same original tree as
> my rebase-base to begin with, which would make the rebase rather
> pointless.

Another fun option would be to put notes on patch-ids. That would of course be horrifically slow to look up, but would survive many cherry-picks and rebases (but not all, of course).

I don't know if that is useful or not, but I don't see any reason why the discussed implementation would forbid it (somebody would just have to implement the lookups at a useful spot).

> > On naming.  I strongly support a ref/notes/sha1/sha1 approach.
> I think you meant refs/notes:<first byte in hex>/<rest of bytes>/<some
> arbitrary SHA-1>?

You seem to be in favor of the fan-out. Out of curiosity, did you ever do numbers on whether the fan-out is actually helpful?

> I am rather supporting refs/nots:<first byte in hex>/<rest of bytes>
> being either a blob, or a tree containing human readable tags, such as
> "bugfix" or "review" or some such.

Yes, I am in favor of the "tree or blob" idea, too. I want this to not just be about "I am a person writing a note" but "arbitrary data attached to an object after it has been created". And that means thinking up front about managing the namespace.

-Peff