Re: [PATCH] tests: prefer host Git to verify chainlint self-checks

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

Patrick Steinhardt <ps@pks.im> writes:

> To accomodate for cases where the host system has no Git installation we
> use the locally-compiled version of Git. This can result in problems
> though when the Git project's repository is using extensions that the
> locally-compiled version of Git doesn't understand. It will refuse to
> run and thus cause the checks to fail.
>
> Fix this issue by prefering the host's Git resolved via PATH. If it
> doesn't exist, then we fall back to the locally-compiled Git version and
> diff as before.
>
> Signed-off-by: Patrick Steinhardt <ps@pks.im>
> ---
>
> I've started to dogfood the reftable backend on my local machine and
> have converted many repositories to use the reftable backend. This
> surfaced the described issue because the repository now sets up the
> "extensions.refStorage" extension, and thus "check-chainlint" fails
> depending on which versions of Git I'm trying to compile and test.

I do not think "prefer host Git" is necessarily a good idea; falling
back to use host Git is perfectly fine, of course.

Other than that, I agree with the motivation.

>  t/Makefile | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/t/Makefile b/t/Makefile
> index 225aaf78ed..8b7f7aceaa 100644
> --- a/t/Makefile
> +++ b/t/Makefile
> @@ -111,7 +111,9 @@ check-chainlint:
>  	if test -f ../GIT-BUILD-OPTIONS; then \
>  		. ../GIT-BUILD-OPTIONS; \
>  	fi && \
> -	if test -x ../git$$X; then \
> +	if command -v git >/dev/null 2>&1; then \
> +		DIFFW="git --no-pager diff -w --no-index"; \
> +	elif test -x ../git$$X; then \
>  		DIFFW="../git$$X --no-pager diff -w --no-index"; \
>  	else \
>  		DIFFW="diff -w -u"; \