Merge branch 'jc/commit-s-subject-is-not-a-footer'

* jc/commit-s-subject-is-not-a-footer:
  builtin-commit.c: fix logic to omit empty line before existing footers

builtin-commit.c

@@ -530,7 +530,7 @@ static int prepare_to_commit(const char *index_file, const char *prefix,
 		for (i = sb.len - 1; i > 0 && sb.buf[i - 1] != '\n'; i--)
 			; /* do nothing */
 		if (prefixcmp(sb.buf + i, sob.buf)) {
-			if (!ends_rfc2822_footer(&sb))
+			if (!i || !ends_rfc2822_footer(&sb))
 				strbuf_addch(&sb, '\n');
 			strbuf_addbuf(&sb, &sob);
 		}

t/t7502-commit.sh

@@ -258,4 +258,13 @@ test_expect_success 'Hand committing of a redundant merge removes dups' '
 
 '
 
+test_expect_success 'A single-liner subject with a token plus colon is not a footer' '
+
+	git reset --hard &&
+	git commit -s -m "hello: kitty" --allow-empty &&
+	git cat-file commit HEAD | sed -e "1,/^$/d" >actual &&
+	test $(wc -l <actual) = 3
+
+'
+
 test_done