Re: config.status and /bin/sh on Solaris

[Dimitrios Apostolou]

On Sat, 28 Jan 2017, Dimitrios Apostolou wrote:
> So the configure script goes like this:
>
>  if test x$as_have_required = xyes && (eval "$as_suggested") 2>/dev/null;
>  then :
>  else
>    [ ... Almost 100 lines never executed ... ]
>  fi
> fi
> SHELL=${CONFIG_SHELL-/bin/sh}
> export SHELL

Digging deeper into this, I believe this is the relevant code, file 
m4sh.m4, macro _AS_DETECT_BETTER_SHELL (with slight indentation edits by 
myself while struggling to follow logic):

[if test "x$CONFIG_SHELL" = x; then
  as_bourne_compatible="AS_ESCAPE(_m4_expand([_AS_BOURNE_COMPATIBLE]))"
  _AS_DETECT_EXPAND([as_required], [_AS_DETECT_REQUIRED_BODY])
  _AS_DETECT_EXPAND([as_suggested], [_AS_DETECT_SUGGESTED_BODY])
  AS_IF([_AS_RUN(["$as_required"])],
        [as_have_required=yes],
        [as_have_required=no])

  AS_IF([test x$as_have_required = xyes && _AS_RUN(["$as_suggested"])],
    [],
    [ ... long snippet trying various shells in various directories
          and setting CONFIG_SHELL accordingly ...
    ]
  )
fi
SHELL=${CONFIG_SHELL-/bin/sh}
export SHELL


In my case, /usr/xpg4/bin/sh is a capable-enough shell, thus 
as_have_required is *yes* and _AS_RUN(["$as_suggested"]) *succeeds*, thus 
the long snippet that tries all shells, is skipped!

By reading this, it seems that the intent is to set SHELL to the 
*currently running shell interpreter*, since it passed all tests. But that 
one is not /bin/sh, since the script was manually executed with "sh 
./configure" and a modified PATH.

A slight improvement would be to change the last line to search for the 
first "sh" in PATH:

SHELL=${CONFIG_SHELL-`command -v sh`}

The best solution would be to detect the currently running interpreter. 
But how?

Thanks,
Dimitris