unpack-trees: preserve index extensions

diff --git a/read-cache.c b/read-cache.c
index 0d0081a11b858227d3f55ebbc21f04bd49875f68..79827a4d71091cf6493a0ed4740cec94c4814b38 100644 (file)
--- a/read-cache.c
+++ b/read-cache.c
@@ -2628,3 +2628,9 @@ void stat_validity_update(struct stat_validity *sv, int fd)
                fill_stat_data(sv->sd, &st);
        }
 }
+
+void move_index_extensions(struct index_state *dst, struct index_state *src)
+{
+       dst->untracked = src->untracked;
+       src->untracked = NULL;
+}