Re: [PATCH 07/17] commit: increase commit message buffer size

[Brandon Williams <bmwill@google.com>]

On 07/09, Stefan Beller wrote:
> On Mon, Jul 9, 2018 at 6:09 AM Derrick Stolee <stolee@gmail.com> wrote:
> >
> > On 7/8/2018 7:36 PM, brian m. carlson wrote:
> > > 100 bytes is not sufficient to ensure we can write a commit message
> > > buffer when using a 32-byte hash algorithm.  Increase the buffer size to
> > > ensure we have sufficient space.
> > >
> > > Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
> > > ---
> > >   refs/files-backend.c | 2 +-
> > >   1 file changed, 1 insertion(+), 1 deletion(-)
> > >
> > > diff --git a/refs/files-backend.c b/refs/files-backend.c
> > > index a9a066dcfb..252f835bae 100644
> > > --- a/refs/files-backend.c
> > > +++ b/refs/files-backend.c
> > > @@ -1587,7 +1587,7 @@ static int log_ref_write_fd(int fd, const struct object_id *old_oid,
> > >       char *logrec;
> > >
> > >       msglen = msg ? strlen(msg) : 0;
> > > -     maxlen = strlen(committer) + msglen + 100;
> > > +     maxlen = strlen(committer) + msglen + 200;
> > >       logrec = xmalloc(maxlen);
> > >       len = xsnprintf(logrec, maxlen, "%s %s %s\n",
> > >                       oid_to_hex(old_oid),
> >
> > nit: 100 is not enough anymore, but wasn't a very descriptive value. 200
> > may be enough now, but I'm not sure why.
> 
> That line was touched in by Michael in 7bd9bcf372d (refs: split filesystem-based
> refs code into a new file, 2015-11-09) and before that by Ronnie in 2c6207abbd6
> (refs.c: add a function to append a reflog entry to a fd, 2014-12-12)
> and introduced
> by Junio in 8ac65937d03 (Make sure we do not write bogus reflog
> entries., 2007-01-26)
> and it appears to me that 2*40 + 5 ought to be sufficient, but no
> comments or commit
> messages are found as to why we rather choose 100.

Whats the reason for not using a strbuf here so that we don't have to
play with magic numbers?

-- 
Brandon Williams