From: Brian Gernhardt <benji@silverinsanity.com>
Date: Wed, 11 Jul 2007 19:48:51 GMT
Subject: Re: Getting version output for a file.
Message-ID: <A084830C-F1CD-4EDC-A13D-573DFC68DF77@silverinsanity.com>
In-Reply-To: <86abu3dv9o.fsf@lola.quinscape.zz>

I don't know lisp very well, and elisp not at all, but I can help you  
with what command lines would give you the results you might want.

On Jul 11, 2007, at 7:39 AM, David Kastrup wrote:

> (vc-git-previous-version FILE REV)
> Return the version number immediately preceding REV for FILE,
> or nil if there is no previous version.

If you want the last revision where the file was altered, you could  
easily use

git rev-list -2 $current_rev -- $file | tail -1

The result would be a SHA-1 of the next commit where the file was  
altered.

> (vc-git-next-version FILE REV)
> Return the version number immediately following REV for FILE,
> or nil if there is no previous version.

This is a little more problematic as git doesn't have forward links  
in it's history.  If you have a ref to start with (HEAD is a good one  
to use, if you don't have anything else) you could use a similar  
command to the above

git rev-list $ref -- $file | grep -C1 -m1 $current_rev | head -1

If you don't have a ref to start from, you could use --all, but that  
may not be what the user expects.

If you want a human readable name for either you could use name-rev.   
(Add "| git name-rev --stdin" to the end of the above.)  It places a  
human readable name after the SHA-1 in parentheses.  (example:  
"54dadbdb29668fbd51effefd0a0c65d915f5422b (master~3)")

~~ Brian