Re: Autoconf 2.53: improved fix for problems with CONFIG_SHELL=bash

[Paul Eggert]

> From: Akim Demaille <address@hidden>
> Date: 19 Mar 2002 16:52:24 +0100

> I'm against moving bash at the end.

Likewise, given that we seem to have more problems with ksh than bash
in practice.

> Actually, I'd be happy to see zsh promoted to a higher rank too,

I would put it between bash and ksh.

> So maybe we should just keep SHELL != CONFIG_SHELL.

Sorry, I don't understand this point.  I don't think Aaron Ucko was
suggesting that we use the same variable for both concepts.

Going back to his original message, I'm afraid that I don't understand
his bug report either.  The Bash 2.05a manual says that Bash reads
.bashrc only if it is an interactive shell that is not a login shell,
or if it is being run by rshd.  Surely neither condition applies here.

Perhaps the installers had set BASH_ENV to point to their .bashrc?
That might explain the problem.  There is a similar problem with ENV
in various shells, including Bash in some cases.  Sounds a bit weird,
though -- why would someone put a "cd" command in their BASH_ENV?

Anyway, If my guess is correct, the following untested patch should
fix things.  But I would like some confirmation and advice before
installing this.


2002-03-19  Paul Eggert  <address@hidden>

        * lib/m4sugar/m4sh.m4 (_AS_LINENO_PREPARE): Unset ENV and
        BASH_ENV when reinvoking the shell, to work around problems
        with installers who put "cd" commands in their environments.

--- m4sh.m4.~1.76.~     2002-03-18 22:13:55.000000000 -0800
+++ m4sh.m4     2002-03-19 17:49:08.147121000 -0800
@@ -507,6 +507,8 @@ m4_define([_AS_LINENO_PREPARE],
         case $as_dir in
         /*)
           if ("$as_dir/$as_base" -c '_AS_LINENO_WORKS') 2>/dev/null; then
+            AS_UNSET(ENV, /dev/null)
+            AS_UNSET(BASH_ENV, /dev/null)
             CONFIG_SHELL=$as_dir/$as_base
             export CONFIG_SHELL
             exec "$CONFIG_SHELL" "$[0]" ${1+"address@hidden"}