Re: [PATCH 4/4] hooks--update.sample: use hash-agnostic null OID

> The update sample hook has the null OID hardcoded as 40 zeros. However,
> with the introduction of SHA-256 support, this assumption no longer
> holds true. Replace the hardcoded $z40 with a call to
> `git rev-parse --null-oid` so the sample hook becomes hash-agnostic.
>
> Signed-off-by: Denton Liu <liu.denton@gmail.com>
> ---
> diff --git a/templates/hooks--update.sample b/templates/hooks--update.sample
> @@ -60,7 +60,7 @@ esac
> -zero="0000000000000000000000000000000000000000"
> +zero="$(git rev-list --null-oid)"