Subject: Re: [PATCH v2] t0001: fix broken not-quite getcwd(3) test in bed67874e2

From: Junio C Hamano <[email-masked]>
Date: Fri, 30 Jul 2021 10:16:51 -0700

Ævar Arnfjörð Bjarmason  <[email-masked]> writes:

> The problem with that fix is that while its analysis of the problem is
> correct, it doesn't actually call getcwd(3), instead it invokes "pwd
> -P". There is no guarantee that "pwd -P" is going to call getcwd(3),
> as opposed to e.g. being a shell built-in.
>
> On AIX under both bash and ksh this test breaks because "pwd -P" will
> happily display the current working directory, but getcwd(3) called by
> the "git init" we're testing here will fail to get it.

Well described.  And logically it leads to "when we want to know
getcwd() is OK to use, trying to run getcwd() to see it works is the
right way to do so", which is your test-getcwd.c?  Nice.

Will queue.

> diff --git a/t/helper/test-tool.c b/t/helper/test-tool.c
> index 490ac026c51..3ce5585e53a 100644
> --- a/t/helper/test-tool.c
> +++ b/t/helper/test-tool.c
> @@ -33,6 +33,7 @@ static struct test_cmd cmds[] = {
>  	{ "fast-rebase", cmd__fast_rebase },
>  	{ "genrandom", cmd__genrandom },
>  	{ "genzeros", cmd__genzeros },
> +	{ "getcwd", cmd__getcwd },
>  	{ "hashmap", cmd__hashmap },
>  	{ "hash-speed", cmd__hash_speed },
>  	{ "index-version", cmd__index_version },
> diff --git a/t/helper/test-tool.h b/t/helper/test-tool.h
> index f8dc266721f..9f0f5228508 100644
> --- a/t/helper/test-tool.h
> +++ b/t/helper/test-tool.h
> @@ -23,6 +23,7 @@ int cmd__example_decorate(int argc, const char **argv);
>  int cmd__fast_rebase(int argc, const char **argv);
>  int cmd__genrandom(int argc, const char **argv);
>  int cmd__genzeros(int argc, const char **argv);
> +int cmd__getcwd(int argc, const char **argv);
>  int cmd__hashmap(int argc, const char **argv);
>  int cmd__hash_speed(int argc, const char **argv);
>  int cmd__index_version(int argc, const char **argv);
> diff --git a/t/t0001-init.sh b/t/t0001-init.sh
> index acd662e403b..df544bb321f 100755
> --- a/t/t0001-init.sh
> +++ b/t/t0001-init.sh
> @@ -356,7 +356,10 @@ test_lazy_prereq GETCWD_IGNORES_PERMS '
>  	chmod 100 $base ||
>  	BUG "cannot prepare $base"
>  
> -	(cd $base/dir && /bin/pwd -P)
> +	(
> +		cd $base/dir &&
> +		test-tool getcwd
> +	)
>  	status=$?
>  
>  	chmod 700 $base &&