Re: [PATCH 2/2] avoid using sha1_to_hex output as printf format
- From
Junio C Hamano <gitster@pobox.com>
- Date
- Jul 8, 2016, 17:02 UTC
- Message-ID
- <xmqqinwgm5aa.fsf@gitster.mtv.corp.google.com>
- In-Reply-To
- <20160708103515.GA19705@sigill.intra.peff.net>
Jeff King <peff@peff.net> writes:
Show 22 quoted lines
> On Fri, Jul 08, 2016 at 05:25:26AM -0400, Jeff King wrote:
>
>> diff --git a/commit.c b/commit.c
>> index 3f4f371..9603379 100644
>> --- a/commit.c
>> +++ b/commit.c
>> @@ -1623,7 +1623,7 @@ void print_commit_list(struct commit_list *list,
>> {
>> for ( ; list; list = list->next) {
>> const char *format = list->next ? format_cur : format_last;
>> - printf(format, oid_to_hex(&list->item->object.oid));
>> + printf(format, "%s", oid_to_hex(&list->item->object.oid));
>
> Urgh, this second hunk is clearly bogus. This is a -Wformat-nonliteral
> problem, but not because of oid_to_hex(), but rather because of
> "format". :-/
>
> Here's a corrected patch. But as this has demonstrated the dangers of
> churn, and as it doesn't really get us meaningfully closer to being able
> to use -Wformat-nonliteral, perhaps the best course of action is to just
> drop it (I do think the "walker_say" patch has more inherent value as a
> cleanup, though).Hmm. While both do look correct, and it is a no-brainer to take this (corrected) patch, I am not sure how much we care about walkers these days.
As to the hunk to commit.c that was dropped in this round, the only caller of print_commit_list() is bisect.c, and it passes "%s\n" to format_cur and format_last, it seems, so that suggests a more obvious direction for cleaning things up, I would say.
Show 25 quoted lines
> -- >8 -- > Subject: [PATCH] avoid using sha1_to_hex output as printf format > > We know that it should not contain any percent-signs, but > it's a good habit not to feed non-literals to printf > formatters. > > Signed-off-by: Jeff King <peff@peff.net> > --- > builtin/worktree.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/builtin/worktree.c b/builtin/worktree.c > index e866844..cce555c 100644 > --- a/builtin/worktree.c > +++ b/builtin/worktree.c > @@ -262,7 +262,7 @@ static int add_worktree(const char *path, const char *refname, > */ > strbuf_reset(&sb); > strbuf_addf(&sb, "%s/HEAD", sb_repo.buf); > - write_file(sb.buf, sha1_to_hex(null_sha1)); > + write_file(sb.buf, "%s", sha1_to_hex(null_sha1)); > strbuf_reset(&sb); > strbuf_addf(&sb, "%s/commondir", sb_repo.buf); > write_file(sb.buf, "../..");