Subject: Re: [PATCH] test-lib-functions: avoid non POSIX ERE in test_dir_is_empty()

From: Taylor Blau <[email-masked]>
Date: Thu, 26 Aug 2021 00:24:14 -0400

On Wed, Aug 25, 2021 at 08:17:10PM -0700, Carlo Marcelo Arenas Belón wrote:
> 0be7d9b73d (test-lib: add test_dir_is_empty(), 2014-06-19) uses an
> ERE through the egrep tool (which is not POSIX) using an ? operator
> that isn't either.
>
> replace invocation with two equivalent simpler BRE instead.
>
> Signed-off-by: Carlo Marcelo Arenas Belón <[email-masked]>
> ---
>  t/test-lib-functions.sh | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/t/test-lib-functions.sh b/t/test-lib-functions.sh
> index e28411bb75..2803c97df3 100644
> --- a/t/test-lib-functions.sh
> +++ b/t/test-lib-functions.sh
> @@ -790,7 +790,7 @@ test_path_exists () {
>  test_dir_is_empty () {
>  	test "$#" -ne 1 && BUG "1 param"
>  	test_path_is_dir "$1" &&
> -	if test -n "$(ls -a1 "$1" | egrep -v '^\.\.?$')"
> +	if test -n "$(ls -a1 "$1" | grep -v '^\.$' | grep -v '^\.\.$')"

This replacement is correct, but I'm not sure that I necessarily find it
simpler. If we really are concerned about egrep usage, then

    if test -n "$(find "$1" | grep -v '^\.$')"

would suffice. But it looks like we are fairly OK with egrep in t (`git
grep 'egrep' -- t | wc -l` turns up 19 matches), so I'm not sure the
change is necessary in the first place.

Thanks,
Taylor