Re: [PATCH 07/17] commit: increase commit message buffer size
- Date: Mon, 09 Jul 2018 10:34:06 -0700
- From: Junio C Hamano <gitster@xxxxxxxxx>
- Subject: Re: [PATCH 07/17] commit: increase commit message buffer size
Brandon Williams <bmwill@xxxxxxxxxx> writes:
>> > > 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?
Quite a legitimate question.
I suspect that the reason is because the code (even though it now
sits in a file that was relatively recently creted) predates either
the introduction or wide adoption of strbuf.
Back when 6de08ae6 ("Log ref updates to logs/refs/<ref>",
2006-05-17) was done, we already had strbuf.c, but it only had
read_line() and nothing else back then, so it wouldn't have been
possible to use a strbuf there.