Re: [PATCH] Prototype PATH_MAX length detection in tests, demonstrated in t0001-init.sh

From: Johannes Sixt <j6t@kdbg.org>
Date: Jan 9, 2018, 23:00 UTC
Message-ID: <47197839-720f-3c8d-729c-3fcb615aeb36@kdbg.org>
In-Reply-To: <f08a9506afb73c57751d3d413bfb433a.squirrel@secure.elehost.com>

Am 09.01.2018 um 19:12 schrieb Randall S. Becker:

Show 11 quoted lines

> This patch create a configuration variable PATH_MAX that
> corresponds with the value in limits.h. The value of PATH_MAX,
> if supplied, is added to BASIC_CFLAGS and will validate with
> limits.h. PATH_MAX is also added to GIT-BUILD-OPTIONS and is
> available in the git test suite.
> 
> This patch also creates a test_expected_success_cond, taking a
> single function as first argument. In the t0001-init.sh case,
> subtest 34 this function is test_path_max_is_sane, although any
> 0/1 returning function can be used. The prototype allows the long base
> path test to be skipped if PATH_MAX is less than 2048 bytes.

OK, but...

Show 13 quoted lines

> diff --git a/t/t0001-init.sh b/t/t0001-init.sh
> index c4814d2..58dad87 100755
> --- a/t/t0001-init.sh
> +++ b/t/t0001-init.sh
> @@ -315,7 +315,7 @@ test_expect_success 'init with separate gitdir' '
>   	test_path_is_dir realgitdir/refs
>   '
> 
> -test_expect_success 'init in long base path' '
> +test_expect_success_cond 'test_path_max_is_sane' 'init in long base path' '
>   	# exceed initial buffer size of strbuf_getcwd()
>   	component=123456789abcdef &&
>   	test_when_finished "chmod 0700 $component; rm -rf $component" &&

... why would you want to skip this test? If I'm reading the test case correctly, it requires only a path length of 127 plus whatever your build directory is plus a score for the trash directory. That should pose a problem only if your system is even more crippled than Windows with its PATH_MAX of 260.

Show 12 quoted lines

> +test_path_max_is_sane() {
> +	if test -z "$PATH_MAX"
> +	then
> +		retval=1
> +	elif test $PATH_MAX -ge 2048
> +	then
> +		retval=1
> +	else
> +		retval=0
> +	fi
> +	return "$retval"
> +}

This can probably be reduced to

test_path_max_is_sane () {
	test "${PATH_MAX:-4000}" -ge 2048
}

(Style note: we have a blank before the () pair in shell scripts.)

-- Hannes