diff --git a/new.diff b/new.diff
new file mode 100644
index 0000000..b73b71b
--- /dev/null
+++ b/new.diff
@@ -0,0 +1,125 @@
+Index: post-build-checks-1.0/checks/09-check-packaged-twice
+===================================================================
+--- post-build-checks-1.0.orig/checks/09-check-packaged-twice	2011-10-20 11:57:54.000000000 +0200
++++ post-build-checks-1.0/checks/09-check-packaged-twice	2011-11-25 19:07:11.509942810 +0100
+@@ -1,61 +1,73 @@
+-#!/usr/bin/perl
++#!/usr/bin/perl -w
+ # search for files packaged more than once
++# it is an error if such a file exists but the packages do not conflict
+ #
+ use strict;
+ my $had_errors = 0;
+-my $build_root = $::ENV{BUILD_ROOT};
+-my @RPMS = ();
++my $build_root = $::ENV{BUILD_ROOT} || '/';
+ 
+ my $TOPDIR = '/usr/src/packages';
+ $TOPDIR = '/.build.packages' if -d "$build_root/.build.packages";
+ 
+-open ( ALL_RPMS , "find $build_root$TOPDIR/RPMS -name \"*.rpm\" |");
+-while ( my $cur = <ALL_RPMS> ) {
+-    chomp ( $cur );
+-    $cur =~ s/^$build_root//;
+-    push @RPMS, $cur;
++sub conflicts {
++    my ($rpm1, $rpm2) = @_;
++    open (F, "chroot $build_root rpm -qp --qf '[%{CONFLICTNAME} %{CONFLICTFLAGS} %{CONFLICTVERSION}\n]' $rpm1|");
++    my @conflicts = <F>;
++    close F;
++    chomp @conflicts;
++    return 0 unless @conflicts;
++    open (F, "chroot $build_root rpm -qp --qf '[%{PROVIDENAME} %{PROVIDEFLAGS} %{PROVIDEVERSION}\n]' $rpm2|");
++    my @provides = <F>;
++    close F;
++    for my $c (@conflicts) {
++        my @cc = split(' ', $c, 3);
++        $cc[0] =~ s/^otherproviders\((.*)\)$/$1/;
++        for my $p (@provides) {
++            my @pp = split(' ', $p, 3);
++            next unless $cc[0] eq $pp[0];
++            # add complex logic here if needed
++            return 1;
++        }
++    }
++    return 0;
+ }
+-close ( ALL_RPMS );
+ 
+-if ( $#RPMS < 1 ) {
+-    exit 0;
++open (ALL_RPMS, "find $build_root$TOPDIR/RPMS -name \"*.rpm\" |");
++my @rpms = <ALL_RPMS>;
++chomp @rpms;
++close ALL_RPMS;
++
++exit 0 if @rpms < 2;
++
++my %allfiles;
++my %pkg2rpm;
++
++for my $rpm (@rpms) {
++    $rpm =~ s/^$build_root//;
++    open (FILES, "chroot $build_root rpm -qp --qf '[%{FILEMODES:perms} %{NAME} %{FILENAMES}\n]' $rpm|");
++    my @files = <FILES>;
++    chomp @files;
++    close FILES;
++    # ignore dirs
++    @files = grep {!/^d/} @files;
++    for my $file (@files) {
++        next unless $file =~ /^\S+ (\S+) (.*)$/;
++        $allfiles{$2}->{$1} = 1;
++        $pkg2rpm{$1} = $rpm;
++    }
+ }
+ 
+-my %FILES = ();
+-
+-for my $cur (@RPMS) {
+-  my $rpmname = `chroot $build_root rpm -qp --qf '%{NAME}' $cur`;
+-  open ( FILELIST , "chroot $build_root rpm -qplv $cur |");
+-  while ( my $file = <FILELIST> ) {
+-     chomp ( $file );
+-     next if ( $file =~ /^d/ );
+-     my @line = split ('\s+',$file);
+-     my $filename = "";
+-     while (my $file_too = pop(@line)) {
+-        if ($file_too eq "->") {
+-	    # this was a symlink target
+-	    $filename = "";
+-        } else {
+-	    $filename = $file_too.($filename eq "" ? "" : " ").$filename;
+-        }
+-        last if ($#line == 7);
+-     }
+-     if ( $FILES{$filename} ) {
+-	#printf "ERROR: $rpmname: $filename already packaged in package $FILES{$filename}\n";
+-	printf "WARNING: $rpmname: $filename already packaged in package $FILES{$filename}\n";
+-	$had_errors = 1;
+-	$FILES{$filename} .= ",$rpmname";
+-     } else {
+-	$FILES{$filename} = $rpmname;
+-     }
+-  }
+-  close ( FILELIST );
++for my $file (keys %allfiles) {
++    my @pkgs = keys %{$allfiles{$file}};
++    next if @pkgs < 2;
++    while (@pkgs) {
++        my $p1 = shift @pkgs;
++	for my $p2 (@pkgs) {
++	    next if conflicts($pkg2rpm{$p1}, $pkg2rpm{$p2}) || conflicts($pkg2rpm{$p2}, $pkg2rpm{$p1});
++	    print "ERROR: $file is packaged in both $p1 and $p2, and the packages do not conflict\n";
++	    $had_errors = 1;
++	}
++    }
+ }
+ 
+-#if ( $had_errors ) {
+-#   printf "found ERRORS\n";
+-#   exit 1;
+-#}
+-
+-exit 0;
+-
++exit $had_errors;
diff --git a/post-build-checks.changes b/post-build-checks.changes
index 1c4b23b..0a3a981 100644
--- a/post-build-checks.changes
+++ b/post-build-checks.changes
@@ -1,3 +1,8 @@
+-------------------------------------------------------------------
+Fri Nov 25 21:59:53 UTC 2011 - coolo@suse.com
+
+- make "packaged twice" fatal if packages do not conflict
+
 -------------------------------------------------------------------
 Thu Oct 20 10:01:31 UTC 2011 - ro@suse.com
 
diff --git a/post-build-checks.spec b/post-build-checks.spec
index a7868f1..2f84b30 100644
--- a/post-build-checks.spec
+++ b/post-build-checks.spec
@@ -36,6 +36,7 @@ Url:            http://gitorious.org/opensuse/post-build-checks
 # make package
 #
 Source0:        %{name}-%{version}.tar.bz2
+Patch0:         new.diff
 BuildArch:      noarch
 BuildRoot:      %{_tmppath}/%{name}-%{version}-build
 
@@ -52,6 +53,7 @@ it may not be a good idea to install this to a running system:
 
 %prep
 %setup -q
+%patch0 -p1
 
 %build
 # nothing to do