Re: [PATCH] config: correct '**' matching in includeIf patterns

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

Nguyễn Thái Ngọc Duy  <pclouds@gmail.com> writes:

> The current wildmatch() call for includeIf's gitdir pattern does not
> pass the WM_PATHNAME flag. Without this flag, '*' is treated _almost_
> the same as '**' (because '*' also matches slashes) with one exception:
>
> '/**/' can match a single slash. The pattern 'foo/**/bar' matches
> 'foo/bar'.
>
> But '/*/', which is essentially what wildmatch engine sees without
> WM_PATHNAME, has to match two slashes (and '*' matches nothing). Which
> means 'foo/*/bar' cannot match 'foo/bar'. It can only match 'foo//bar'.
>
> The result of this is the current wildmatch() call works most of the
> time until the user depends on '/**/' matching no path component. The
> fix is straightforward.
>
> Reported-by: Jason Karns <jason.karns@gmail.com>
> Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
> ---
>  Sorry I didn't notice this until Taylor's reply. Not sure how to
>  explain git-lfs behavior though.
>
>  config.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)

The analysis above is very good, and the updated code is a natural
consequence of the analysis; very well done.

Would it be easy to protect this fix from future breakages with a
test or two?

> diff --git a/config.c b/config.c
> index 0f0cdd8c0f..c2846df3f1 100644
> --- a/config.c
> +++ b/config.c
> @@ -242,7 +242,7 @@ static int include_by_gitdir(const struct config_options *opts,
>  	}
>  
>  	ret = !wildmatch(pattern.buf + prefix, text.buf + prefix,
> -			 icase ? WM_CASEFOLD : 0);
> +			 WM_PATHNAME | (icase ? WM_CASEFOLD : 0));
>  
>  	if (!ret && !already_tried_absolute) {
>  		/*