my $path = '/tmp/open';
-d $path and die "remove $path first\n";
mkdir $path;
for (qw(foo bar quux)) {
    open my $fh, '>',"$path/$_";
}
mkdir "$path/baz";
for (qw(blorf blorfldyick)) {
    open my $fh,'>', "$path/baz/$_";
}
opendir my $dh1, $path;
while(readdir $dh1) {
    next if /^\.\.?$/;
    print "read(dh1): $path/$_\n";
    if (-d "$path/$_") {
        opendir my $dh2, "$path/$_" or die;
        # emulate external change directory to symlink
        rename "$path/$_","$path/fie";
        symlink "$path/fie", "$path/$_" or die;
        # end emulate
        if(-l "$path/$_") { 
            print "bogus change to $path/$_:\n";
            print "  $path/$_ points to ",readlink "$path/$_","\n";
        }
        while (my $e = readdir $dh2) {
            next if $e =~ /^\.\.?$/;
            print "read(dh2): $e\n";
        }
    }
}
__END__
read(dh1): /tmp/open/foo
read(dh1): /tmp/open/quux
read(dh1): /tmp/open/baz
bogus change to /tmp/open/baz:
  /tmp/open/baz points to /tmp/open/fie
read(dh2): blorf
read(dh2): blorfldyick
read(dh1): /tmp/open/bar