unpack-trees: add a note about path invalidation

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/unpack-trees.c b/unpack-trees.c
index f9efee0836a20e7072477ae0f3de7c9e1a29ff78..c07a6cd646bc8c4c436b830a6d3de7dee95be86f 100644 (file)
--- a/unpack-trees.c
+++ b/unpack-trees.c
@@ -1552,6 +1552,17 @@ static int verify_uptodate_sparse(const struct cache_entry *ce,
        return verify_uptodate_1(ce, o, ERROR_SPARSE_NOT_UPTODATE_FILE);
 }
 
+/*
+ * TODO: We should actually invalidate o->result, not src_index [1].
+ * But since cache tree and untracked cache both are not copied to
+ * o->result until unpacking is complete, we invalidate them on
+ * src_index instead with the assumption that they will be copied to
+ * dst_index at the end.
+ *
+ * [1] src_index->cache_tree is also used in unpack_callback() so if
+ * we invalidate o->result, we need to update it to use
+ * o->result.cache_tree as well.
+ */
 static void invalidate_ce_path(const struct cache_entry *ce,
                               struct unpack_trees_options *o)
 {