[PATCH 2/6] shallow: only add shallow graft points to new shallow file

for_each_commit_graft() goes through all graft points and shallow
boudaries are just one special kind of grafting. If $GIT_DIR/shallow
and $GIT_DIR/info/grafts are both present, write_shallow_commits may
catch both sets, accidentally turning some graft points to shallow
boundaries. Don't do that.

Signed-off-by: Nguyễn Thái Ngọc Duy <redacted>
---
 shallow.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/shallow.c b/shallow.c
index 68dd106..5f626c0 100644
--- a/shallow.c
+++ b/shallow.c

@@ -153,6 +153,8 @@ static int write_one_shallow(const struct commit_graft *graft, void *cb_data)
 {
 	struct write_shallow_data *data = cb_data;
 	const char *hex = sha1_to_hex(graft->sha1);
+	if (graft->nr_parent != -1)
+		return 0;
 	data->count++;
 	if (data->use_pack_protocol)
 		packet_buf_write(data->out, "shallow %s", hex);

-- 
1.8.2.82.gc24b958