Re: [musl] [PATCH 2/2] configure: improve portability of test command

[Rich Felker <dalias@libc.org>]

On Sat, Oct 10, 2020 at 06:51:10PM +0000, Issam E. Maghni wrote:
> > The two commands:
> >  test "$1"
> >  test ! "$1"
> > could not be used reliably on some historical systems. Unexpected results
> > would occur if such a string expression were used and $1 expanded to '!', '(',
> > or a known unary primary. Better constructs are:
> >  test -n "$1"
> >  test -z "$1"
> > respectively.
> > Historical systems have also been unreliable given the common construct:
> >  test "$response" = "expected string"
> > One of the following is a more reliable form:
> >  test "X$response" = "Xexpected string"
> >  test "expected string" = "$response"
> https://pubs.opengroup.org/onlinepubs/9699919799/utilities/test.html#tag_20_128_16

The text you've quoted is about non-conforming, pre-POSIX systems. Is
there an actual system where you're encoutering this problem? It's
always been the intent to assume a POSIX-conforming shell and
utilities for configure, and to require the user to upgrade to one if
they don't have one, because supporting non-conforming shell/utilities
is an endless game of whack-a-mole.

Rich