From: Tony Lindgren <tony@atomide.com>
Date: Wed, 01 Jun 2005 16:55:02 GMT
Subject: Re: [SCRIPT] cg-rpush & locking
Message-ID: <20050601165502.GB20936@atomide.com>
In-Reply-To: <20050601065123.GA23358@cip.informatik.uni-erlangen.de>

* Thomas Glanzmann <sithglan@stud.uni-erlangen.de> [050531 23:56]:
> Hello,
> 
> > Why do you need a lock at all?
> 
> > Just update your HEAD reference last when you push and get it first when 
> > you pull.
> 
> consider the following scenario: Two people push at the same time. One
> HEAD gets actually written, but both think that their changes got
> upstream. Of course the 'upstream' tree is consitent, but incomplete.
> That is why we need a lock. And the lock should be obtained before the
> remote HEAD is retrieved, I think the following scenario is how to
> handle it:
> 
> 	1. acquire remote lock
> 	2. get remote HEAD
> 	3. if remote HEAD is ahead (not included in our history) abort
> 	   and free lock.
> 	4. push objects
> 	5. update remote HEAD with local
> 	6. free remote lock.

Yes, that's basically what the script does. We have several people
committing patches.

Tony