Re: git stash takes excessively long when many untracked files present

[Junio C Hamano <gitster@pobox.com>]

Junio C Hamano <gitster@pobox.com> writes:

> diff --git a/dir.c b/dir.c
> index 910bfcd..02939e2 100644
> --- a/dir.c
> +++ b/dir.c
> @@ -1183,6 +1183,15 @@ static enum path_treatment treat_one_path(struct dir_struct *dir,
>  	    cache_name_exists(path->buf, path->len, ignore_case))
>  		return path_none;
>  
> +	/*
> +	 * A directory can only contain killed files if the index
> +	 * has a path that wants it to be a non-directory.
> +	 */
> +	if ((dir->flags & DIR_COLLECT_KILLED_ONLY) &&
> +	    (dtype == DT_DIR) &&
> +	    !cache_name_exists(path->buf, path->len, ignore_case))
> +		return path_none;
> +

I think this is wrong.

When we are looking at a directory P in the working tree, there are
three cases:

 (1) P exists in the index.  Everything inside the directory P in
     the working tree needs to go when P is checked out from the
     index.

 (2) P does not exist in the index, but there is P/Q in the index.
     We know P will stay a directory when we check out the contents
     of the index, but we do not know yet if there is a directory
     P/Q in the working tree to be killed, so we need to recurse.

 (3) P does not exist in the index, and there is no P/Q in the index
     to require P to be a directory, either.  Only in this case, we
     know that everything inside P will not be killed without
     recursing.

The patch will break with the second case, I think.