Re: Tracking branch history

From: Linus Torvalds <torvalds@osdl.org>
Date: May 13, 2006, 04:38 UTC
Message-ID: <Pine.LNX.4.64.0605122136100.3866@g5.osdl.org>
In-Reply-To: <20060513034051.GA21586@spearce.org>

On Fri, 12 May 2006, Shawn Pearce wrote:

Show 14 quoted lines

> 
> Why not intergrate this into git-update-ref.  Almost every tool which
> deals with a GIT repository (aside from my pure-Java Eclipse plugin
> which is still a major work-in-process) performs ref changes through
> git-udpate-ref.  So just have it append the ref's history to a file:
> 
> 	.git/log/refs/heads/$branch
> 
> where the history records are stored as:
> 
> 	40 byte commit-ish SHA1
> 	<SP>
> 	<committer>
> 	<LF>

Sure. Except it's not really "committer", in the ordinary sense (there's no "commit" for a fast-forward). But yes, re-using that format (with date and all) makes sense.

> Of course a major issue here is locking the log file during the ref
> update, but it looks like it might just be safe to append the entry
> to the log file right after the re_verify and before the rename.

I'd suggest just opening it with O_APPEND, and doing the update with a single write() system call. Let the OS do the locking for you.

		Linus