Re: [PATCH 07/17] commit: increase commit message buffer size
- From
Junio C Hamano <gitster@pobox.com>
- Date
- Jul 9, 2018, 17:34 UTC
- Message-ID
- <xmqqzhz0e2k1.fsf@gitster-ct.c.googlers.com>
- In-Reply-To
- <20180709172716.GA81741@google.com>
Brandon Williams <bmwill@google.com> writes:
Show 29 quoted lines
>> > > 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.