From: Juliusz Chroboczek <juliusz.chroboczek@pps.jussieu.fr>
Date: Mon, 09 May 2005 22:46:10 GMT
Subject: Re: Darcs-git: a few notes for Git hackers
Message-ID: <7ipsw010i5.fsf@lanthane.pps.jussieu.fr>
In-Reply-To: <427FE248.7040403@zytor.com>

>> I see.  Let me know if you decide to use a different name for the
>> lock file so I can switch to using the same one as yours.

> Are you using flock(), or some other contraption that breaks if a
> process dies unexpectedly?

No, I'm using a file that is created by the NFS-safe equivalent of
open(O_CREAT | O_EXCL).  This is what Darcs has been doing basically
forever.

Darcs usually doesn't die unexpectedly -- it's a Haskell program, so
bugs usually manifest themselves with an exception being thrown
allowing Darcs to clean-up after itself.

The one exception is when Darcs gets killed by the OOM killer (which,
as you doubtless know, doesn't give any advance warning to a process,
thus making it impossible for a process to deal with it gracefully).
In such cases, manual intervention is necessary anyway -- a file could
have been written half-way.

                                        Juliusz