Re: How to embed a hash, tag or branch name?

Am 01.08.2009 15:13 schrieb Jakub Narebski:

On Sat, 1 August 2009, Dirk Süsserott wrote:

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Am 31.07.2009 11:52 schrieb Mikko Rapeli:

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On Fri, Jul 31, 2009 at 02:27:50AM -0700, Jakub Narebski wrote:

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You can embed SHA-1 of a _file contents_ (blob) using '$Id: $' keyword
with `ident` attribute - see gitattributes manpage.

Great, thanks!

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The correct solution of embedding version number is to do it at 
_build time_, using e.g. script similar to GIT-VERSION-GEN used by
Git itself and by Linux kernel.  It helps if you tag your releases.

Hi Mikko,

I don't know whether you want to use the "ident" command on your final
binary. With Git, that's pointless, as all source files will have the
same $Id$. So it's perfectly sufficient to have only ONE file enriched
with Git's SHA1.

You are wrong.  In Git $Id$ / $Id: $ expands to SHA-1 id of _blob_ 
(i.e. of file *contents*), not SHA-1 id of a commit.  This way when
switching branches or rewinding branch using git-reset we don't have
to pay huge performance penalty because of `ident`, as we would have
because every file would have to be changed if $Id$ was about commit
id (or if there was $Revision$ or $Author$ implemented).

Ok, sorry about that. Actually I haven't read the concerning docs
*that* well when I figured out that keyword expansion with Git
is not exactly a good idea.

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Suggestion: During build time, compile (and link in) a file (e.g.
version.c) with "-DVERSION=\"$(git describe)\"". My version.c looks like
this:

GIT-VERSION-GEN and various tricks in Makefile do just that, not only
for compiled parts, but also for scripts.

Right, but my explanation shows the overall intention of that.
So, Mikko, have a look at GIT-VERSION-GEN and my suggestion and
use some kind of summary of them.