Re: git and time

From: Tom Prince <tom.prince@ualberta.net>
Date: Sep 28, 2006, 03:26 UTC
Message-ID: <20060928032655.GB3650@socrates.priv>
In-Reply-To: <20060928024938.46785.qmail@web51009.mail.yahoo.com>

On Wed, Sep 27, 2006 at 07:49:37PM -0700, Matthew L Foster wrote:

> How does git ensure that the timestamp in a commit records when it was
> actually created?

Git doesn't try. Git would be perfectly happy if time(2) returned a random value each time. No part of git uses the time in any meaningful way, it just keeps a record of it to display.

> I am not saying throw away creation time, just that local time is more
> preferable and relevant and git/gitweb.cgi should not in any way
> depend on time being configured correctly on each and every git
> server.

git and gitweb.cgi DO NOT in any way depend on time being configured correctly. If some machine has incorrectly configured time, then they will *correctly* display the strange time.

> I think users of kernel.org's repo (or web interface) care
> more about when change X was commited to it than when an author
> created/emailed change X, but perhaps I am wrong or don't understand
> git or both.

Based on comments on this list, it appears that most people don't aren't interested in when exactly a given change hits kernel.org. Several people have pointed out ways to get at the information you want, but none of have seen a need for the information, and so haven't the motivation to implement.

It might help if you gave a use case for the information you want. If you give us a problem that you think the information will solve, the list will probably be able to you how to get at the information you want.

I think you have some misconception of how git works. Git is designed to not lose information. Once a commit is created it is immutable, regardless of whether the time is wrong, or the author, or the commit message, or any bugs in the commit. This is a *feature*. It means you need to go out of your way to destroy history.

> -Matt

Tom