Re: [PATCH 2/2] avoid using sha1_to_hex output as printf format
From: Junio C Hamano <hidden>
Date: 2016-07-08 17:03:02
Jeff King [off-list ref] writes:
On Fri, Jul 08, 2016 at 05:25:26AM -0400, Jeff King wrote:quoted
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.
quoted hunk
-- >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 <redacted> --- 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, "../..");