Subject: Re: [PATCH] t1304: Set LOGNAME even if USER is unset or null

From: Junio C Hamano <[email-masked]>
Date: Sun, 19 Oct 2014 15:49:36 -0700

"W. Trevor King" <[email-masked]> writes:

> Previous LOGNAME discussion:
>
> * Michael Gruber on 2011-05-06 suggesting a discussing a whoami
>   fallback [1] (but whoami isn't POSIX).
> * René Scharfe on 2011-10-14 suggesting USER as a fallback for
>   LOGNAME [2].
> * Matthieu Moy on 2012-09-17 suggesting dropping $LOGNAME in
>   favor of numerical user IDs 'id -u' for a system with multiple
>   usernames sharing the same user ID [3].
>
> Obviously, you can work around the problem with:
>
>   # USER=$(id -u -n) ./t1304-default-acl.sh
>
> so the question is really "Are empty-USER systems worth supporting out
> of the box?".
>
> Cheers,
> Trevor
>
> [1]: http://thread.gmane.org/gmane.comp.version-control.git/172883/focus=172961
> [2]: http://thread.gmane.org/gmane.comp.version-control.git/183586
> [3]: http://thread.gmane.org/gmane.comp.version-control.git/205690/focus=205703
>
>  t/t1304-default-acl.sh | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/t/t1304-default-acl.sh b/t/t1304-default-acl.sh
> index 79045ab..f5422f1 100755
> --- a/t/t1304-default-acl.sh
> +++ b/t/t1304-default-acl.sh
> @@ -26,7 +26,7 @@ test_expect_success 'checking for a working acl setup' '
>  
>  if test -z "$LOGNAME"
>  then
> -	LOGNAME=$USER
> +	LOGNAME="${USER:-$(id -u -n)}"

I'll queue this as-is, but it makes me wonder if we want to do this
without if/then/fi, e.g.

	: ${LOGNAME:=${USER:-$(id -u -n)}

Spelling everything out with if/then/fi is obviously at the other
extreme, i.e.

	if test -z "$LOGNAME"
	then
		if test -n "$USER"
                then
			LOGNAME=$USER
		else
			LOGNAME=$(id -u -n)
		fi
	fi

but it probably is a very bad idea.

More importantly, what if none of the alternatives work?  I
personally feel it is OK to punt and declare test_done early,
instead of giving false positive breakages like you saw without this
patch.