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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.