Re: suggested feature: someone mails me a blob, git please tell me what it is

From: Shawn O. Pearce <spearce@spearce.org>
Date: Feb 17, 2007, 06:10 UTC
Message-ID: <20070217061016.GA27813@spearce.org>
In-Reply-To: <3c6c07c20702160823j316c52f4pe4cf5ca8a882e194@mail.gmail.com>

Mike Coleman <tutufan@gmail.com> wrote:

Show 12 quoted lines

> Here's a suggestion for a git feature, if git doesn't already have it.
> Since git generally doesn't use RCS-style keyword cookies (like
> "$Id$"), it'd be nice to have some other way to identify an installed
> file.  Perhaps you'd want to know exactly what rev a user is running,
> for example.
> 
> It seems like it should be fairly easy, given a blob (the file), for
> git to describe what it knows about it.  For example, it could provide
> a list of commits that it's a part of, etc.  It'd be *really* nice if
> only the output of the sha1sum command on the blob were needed.  (I
> can't recall exactly how git's blob SHA1's are computed--maybe this
> isn't feasible.)

Rather than embedding something like "$Id$" on a per-file basis use the output of git-describe in your build process to insert the string into your executable file(s), and then provide a way to let the user extract it, or insert it with a unique enough pattern that you can grep for it in the output of `strings`.

This is what git does itself. We replace GIT_VERSION in git.c with the output of git-describe during compile time (C preprocessor macro). The value can be printed by the user with `git version`. We also embed it into some Perl scripts.

git-gui does the same thing, but is a Tcl/Tk script.

-- 
Shawn.