Function tree_entry_cmp 

pub fn tree_entry_cmp(
    left_name: &[u8],
    left_mode: u32,
    right_name: &[u8],
    right_mode: u32,
) -> Ordering

Order two tree entries the way Git canonically sorts them: by name bytes, except that a subtree sorts as though its name ended in /. Writing a tree whose entries are in any other order produces a different (wrong) OID.