Merge branch 'sg/commit-cleanup-scissors' into maint

"git commit --cleanup=scissors" was not careful enough to protect
against getting fooled by a line that looked like scissors.

* sg/commit-cleanup-scissors:
  commit: cope with scissors lines in commit message

Author: gitster

t/t7502-commit.sh

@@ -229,14 +229,36 @@ test_expect_success 'cleanup commit messages (scissors option,-F,-e)' '
 	cat >text <<EOF &&
 
 # to be kept
+
+  # ------------------------ >8 ------------------------
+# to be kept, too
 # ------------------------ >8 ------------------------
 to be removed
+# ------------------------ >8 ------------------------
+to be removed, too
+EOF
+
+	cat >expect <<EOF &&
+# to be kept
+
+  # ------------------------ >8 ------------------------
+# to be kept, too
 EOF
-	echo "# to be kept" >expect &&
 	git commit --cleanup=scissors -e -F text -a &&
 	git cat-file -p HEAD |sed -e "1,/^\$/d">actual &&
 	test_cmp expect actual
+'
 
+test_expect_success 'cleanup commit messages (scissors option,-F,-e, scissors on first line)' '
+
+	echo >>negative &&
+	cat >text <<EOF &&
+# ------------------------ >8 ------------------------
+to be removed
+EOF
+	git commit --cleanup=scissors -e -F text -a --allow-empty-message &&
+	git cat-file -p HEAD |sed -e "1,/^\$/d">actual &&
+	test_must_be_empty actual
 '
 
 test_expect_success 'cleanup commit messages (strip option,-F)' '

wt-status.c

@@ -823,10 +823,11 @@ void wt_status_truncate_message_at_cut_line(struct strbuf *buf)
 	const char *p;
 	struct strbuf pattern = STRBUF_INIT;
 
-	strbuf_addf(&pattern, "%c %s", comment_line_char, cut_line);
-	p = strstr(buf->buf, pattern.buf);
-	if (p && (p == buf->buf || p[-1] == '\n'))
-		strbuf_setlen(buf, p - buf->buf);
+	strbuf_addf(&pattern, "\n%c %s", comment_line_char, cut_line);
+	if (starts_with(buf->buf, pattern.buf + 1))
+		strbuf_setlen(buf, 0);
+	else if ((p = strstr(buf->buf, pattern.buf)))
+		strbuf_setlen(buf, p - buf->buf + 1);
 	strbuf_release(&pattern);
 }