am: fix signoff when other trailers are present

If there was no 'Signed-off-by:' trailer but another trailer such as
'Reported-by:' then 'git am --signoff' would add a blank line between
the existing trailers and the added 'Signed-off-by:' line. e.g.

    Rebase accepts '--rerere-autoupdate' as an option but only honors
    it if '-m' is also given. Fix it for a non-interactive rebase by
    passing on the option to 'git am' and 'git cherry-pick'.

    Reported-by: Junio C Hamano <gitster@pobox.com>

    Signed-off-by: Phillip Wood <phillip.wood@dunelm.org.uk>

Fix by using the code provided for this purpose in sequencer.c.
Change the tests so that they check the formatting of the
'Signed-off-by:' lines rather than just grepping for them.

Signed-off-by: Phillip Wood <phillip.wood@dunelm.org.uk>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 1 insertions, 25 deletions

diff --git a/builtin/am.c b/builtin/am.c
index 593c1b5..ba9b57a 100644
--- a/builtin/am.c
+++ b/builtin/am.c
@@ -1188,34 +1188,10 @@ static void NORETURN die_user_resolve(const struct am_state *state)
  */
 static void am_append_signoff(struct am_state *state)
 {
-	char *cp;
-	struct strbuf mine = STRBUF_INIT;
 	struct strbuf sb = STRBUF_INIT;
 
 	strbuf_attach(&sb, state->msg, state->msg_len, state->msg_len);
-
-	/* our sign-off */
-	strbuf_addf(&mine, "\n%s%s\n",
-		    sign_off_header,
-		    fmt_name(getenv("GIT_COMMITTER_NAME"),
-			     getenv("GIT_COMMITTER_EMAIL")));
-
-	/* Does sb end with it already? */
-	if (mine.len < sb.len &&
-	    !strcmp(mine.buf, sb.buf + sb.len - mine.len))
-		goto exit; /* no need to duplicate */
-
-	/* Does it have any Signed-off-by: in the text */
-	for (cp = sb.buf;
-	     cp && *cp && (cp = strstr(cp, sign_off_header)) != NULL;
-	     cp = strchr(cp, '\n')) {
-		if (sb.buf == cp || cp[-1] == '\n')
-			break;
-	}
-
-	strbuf_addstr(&sb, mine.buf + !!cp);
-exit:
-	strbuf_release(&mine);
+	append_signoff(&sb, 0, 0);
 	state->msg = strbuf_detach(&sb, &state->msg_len);
 }