[PATCH v1 2/7] mv: add documentation for check_dir_in_index()

[Shaoxuan Yuan <shaoxuan.yuan02@xxxxxxxxx>]

Using check_dir_in_index without checking if the directory is on-disk
could get a false positive for partially sparsified directory.

Add a note in the documentation to warn potential user.

Signed-off-by: Shaoxuan Yuan <shaoxuan.yuan02@xxxxxxxxx>
---
 builtin/mv.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/builtin/mv.c b/builtin/mv.c
index 4729bb1a1a..c8b9069db8 100644
--- a/builtin/mv.c
+++ b/builtin/mv.c
@@ -132,6 +132,11 @@ static int index_range_of_same_dir(const char *src, int length,
  * Return 0 if such directory exist (i.e. with any of its contained files not
  * marked with CE_SKIP_WORKTREE, the directory would be present in working tree).
  * Return 1 otherwise.
+ *
+ * Note: *always* check the directory is not on-disk before this function
+ * (i.e. using lstat());
+ * otherwise it may return a false positive for a partially sparsified
+ * directory.
  */
 static int check_dir_in_index(const char *name)
 {
-- 
2.37.0