Subject: Re: [PATCH] Perform minimal stat comparison when some stat fields are not set

From: Robin Rosenberg <[email-masked]>
Date: Thu, 6 Dec 2012 02:09:20 +0100 (CET)

----- Ursprungligt meddelande -----
> Robin Rosenberg <[email-masked]> writes:
> 
> > At least JGit does sets uid, gid, ctime, ino and dev fields to zero
> > on update. To Git this looks like the stat data does not match and
> > a full file compare will be forced even it size and mtime match.
> > This
> > is in practice unnecessary. Sense JGit's presence by checking if
> > ino
> > and dev is zero.
> >
> > Signed-off-by: Robin Rosenberg <[email-masked]>
> > ---
> >  read-cache.c | 21 +++++++++++++--------
> >  1 file changed, 13 insertions(+), 8 deletions(-)
> >
> > diff --git a/read-cache.c b/read-cache.c
> > index fda78bc..6f13a22 100644
> > --- a/read-cache.c
> > +++ b/read-cache.c
> > @@ -197,21 +197,26 @@ static int ce_match_stat_basic(struct
> > cache_entry *ce, struct stat *st)
> >  	}
> >  	if (ce->ce_mtime.sec != (unsigned int)st->st_mtime)
> >  		changed |= MTIME_CHANGED;
> > -	if (trust_ctime && ce->ce_ctime.sec != (unsigned
> > int)st->st_ctime)
> > +
> > +	int minimal_stat = (ce->ce_ino == 0 && ce->ce_dev == 0);
> 
> decl-after-stmt.

Ok, btw. Which C version do we adhere to? C99 is quite old by now.

> Besides, is it sane to do this unconditionally to affect people who
> do not use JGit?
> 

Would a config option like core.minstat be better? The name would imply no dynamic detection.

- robin