In this patch, instead of using xnprintf instead of snprintf, which asserts that we don't truncate, we are switching to dynamic allocation with xstrfmt(), , so we can avoid dealing with magic numbers in the code and reduce the cognitive burden from the programmers, because they no longer have to count bytes needed for static allocation. As a side effect of this patch we have also reduced the snprintf() calls, that may silently truncate results if the programmer is not careful. Helped-by: Junio C Hamano <gitster@xxxxxxxxx> Helped-by: Jeff King <peff@xxxxxxxx> Signed-off-by: Elia Pinto <gitter.spiros@xxxxxxxxx> --- This is the third version of the patch. Changes from the first version: I have split the original commit in two, as discussed here http://public-inbox.org/git/20161213132717.42965-1-gitter.spiros@xxxxxxxxx/. Changes from the second version: - Changed the commit message to clarify the purpose of the patch ( as suggested by Junio) https://public-inbox.org/git/xmqqtw95mfo3.fsf@xxxxxxxxxxxxxxxxxxxxxxxxxxx/T/#m2e6405a8a78a8ca1ed770614c91398290574c4a1 builtin/commit.c | 10 ++++------ 1 file changed, 4 insertions(+), 6 deletions(-) diff --git a/builtin/commit.c b/builtin/commit.c index 09bcc0f13..37228330c 100644 --- a/builtin/commit.c +++ b/builtin/commit.c @@ -1526,12 +1526,10 @@ static int git_commit_config(const char *k, const char *v, void *cb) static int run_rewrite_hook(const unsigned char *oldsha1, const unsigned char *newsha1) { - /* oldsha1 SP newsha1 LF NUL */ - static char buf[2*40 + 3]; + char *buf; struct child_process proc = CHILD_PROCESS_INIT; const char *argv[3]; int code; - size_t n; argv[0] = find_hook("post-rewrite"); if (!argv[0]) @@ -1547,11 +1545,11 @@ static int run_rewrite_hook(const unsigned char *oldsha1, code = start_command(&proc); if (code) return code; - n = snprintf(buf, sizeof(buf), "%s %s\n", - sha1_to_hex(oldsha1), sha1_to_hex(newsha1)); + buf = xstrfmt("%s %s\n", sha1_to_hex(oldsha1), sha1_to_hex(newsha1)); sigchain_push(SIGPIPE, SIG_IGN); - write_in_full(proc.in, buf, n); + write_in_full(proc.in, buf, strlen(buf)); close(proc.in); + free(buf); sigchain_pop(SIGPIPE); return finish_command(&proc); } -- 2.11.0.154.g5f5f154