[Module-build-general] [PATCH] Use ExtUtils::AutoInstall for check_prereq if possible

[Autrijus T. <aut...@au...>]

The following patch delegates check_prereq to EU::AI 0.50 (a
not-yet-released version that should handle -conflict modules),
and let EU::AI to handle the (de)installation automatically
before ./Build is run.  Comments welcome.

Thanks,
/Autrijus/

--- Base.pm.orig	Wed Dec 25 20:19:49 2002
+++ Base.pm	Wed Dec 25 20:29:04 2002
@@ -336,6 +336,9 @@
 sub check_prereq {
   my $self =3D shift;
=20
+  return $self->_check_prereq_with_autoinstall
+    if eval { require ExtUtils::AutoInstall; ExtUtils::AutoInstall->VERSIO=
N >=3D 0.50 };
+
   my $failures =3D $self->prereq_failures;
   return 1 unless $failures;
  =20
@@ -346,10 +349,33 @@
       warn "$prefix: $module: $status->{message}\n";
     }
   }
- =20
+
   warn "ERRORS/WARNINGS FOUND IN PREREQUISITES.  You may wish to install t=
he versions ".
        "of the modules indicated above before proceeding with this install=
ation.\n";
   return 0;
+}
+
+sub _check_prereq_with_autoinstall {
+  my $self =3D shift;
+  my $req =3D { map %$_, @{$self->{properties}}{qw/build_requires requires=
/} };
+  my $rec =3D $self->{properties}{recommends};
+  my $con =3D $self->{properties}{conflicts};
+
+  ExtUtils::AutoInstall->import(
+    -version	=3D> 0.50,
+    %$req ? ( -core	=3D> [
+      map { $_ =3D> $req->{$_} } sort grep !/^perl$/, keys %$req
+    ] ) : (),
+    %$rec ? ( 'Recommended Modules' =3D> [
+	map { $_ =3D> $rec->{$_} } sort grep !/^perl$/, keys %$rec
+    ] ) : (),
+    %$con ? ( 'Conflicting Modules' =3D> [
+	-conflict =3D> 1,
+	map { $_ =3D> $con->{$_} } sort grep !/^perl$/, keys %$rec
+    ] ) : (),
+  );
+
+  return ExtUtils::AutoInstall->do_install;
 }
=20
 sub perl_version_to_float {