copy meta munging from JSON-MaybeXS

diff --git a/Makefile.PL b/Makefile.PL
index 8a00724..4b66b8e 100644 (file)
--- a/Makefile.PL
+++ b/Makefile.PL
@@ -4,19 +4,11 @@ use 5.008001;
 use ExtUtils::MakeMaker;
 (do 'maint/Makefile.PL.include' or die $@) unless -f 'META.yml';
 
-WriteMakefile(
+my %WriteMakefileArgs = (
   NAME => 'Safe::Isa',
   VERSION_FROM => 'lib/Safe/Isa.pm',
 
-  MIN_PERL_VERSION => '5.006',
-
-  PREREQ_PM => {
-    'Exporter' => '5.57',
-    'Scalar::Util' => 0,
-  },
-
-  -f 'META.yml' ? () : (
-    META_MERGE => {
+  META_MERGE => {
       'meta-spec' => { version => 2 },
       dynamic_config => 0,
 
@@ -32,8 +24,68 @@ WriteMakefile(
             web => 'https://rt.cpan.org/Public/Dist/Display.html?Name=Safe-Isa',
         },
       },
+  },
+
+  META_ADD => {
+    prereqs => {
+      configure => {
+        requires => {
+          'ExtUtils::MakeMaker' => '0',
+        },
+      },
+      runtime => {
+        requires => {
+          'Exporter' => '5.57',
+          'Scalar::Util' => 0,
+          perl => '5.006',
+        },
+      },
     },
-  ),
+  },
 
   realclean => { FILES => [ 'Distar/', 'MANIFEST*' ] },
 );
+
+my $eumm_version  = eval $ExtUtils::MakeMaker::VERSION;
+
+for (qw(configure build test runtime)) {
+  my $key = $_ eq 'runtime' ? 'PREREQ_PM' : uc $_.'_REQUIRES';
+  next unless exists $WriteMakefileArgs{META_ADD}{prereqs}{$_}
+           or exists $WriteMakefileArgs{$key};
+  my $r = $WriteMakefileArgs{$key} = {
+    %{$WriteMakefileArgs{META_ADD}{prereqs}{$_}{requires} || {}},
+    %{delete $WriteMakefileArgs{$key} || {}},
+  };
+  defined $r->{$_} or delete $r->{$_} for keys %$r;
+}
+
+# dynamic prereqs get added here.
+
+$WriteMakefileArgs{MIN_PERL_VERSION} = delete $WriteMakefileArgs{PREREQ_PM}{perl} || 0;
+
+die 'attention developer: you need to do a sane meta merge here!'
+  if keys %{$WriteMakefileArgs{BUILD_REQUIRES}};
+
+$WriteMakefileArgs{BUILD_REQUIRES} = {
+    %{$WriteMakefileArgs{BUILD_REQUIRES} || {}},
+    %{delete $WriteMakefileArgs{TEST_REQUIRES}}
+} if $eumm_version < 6.63_03;
+
+$WriteMakefileArgs{PREREQ_PM} = {
+    %{$WriteMakefileArgs{PREREQ_PM}},
+    %{delete $WriteMakefileArgs{BUILD_REQUIRES}}
+} if $eumm_version < 6.55_01;
+
+delete $WriteMakefileArgs{CONFIGURE_REQUIRES}
+  if $eumm_version < 6.51_03;
+
+delete $WriteMakefileArgs{MIN_PERL_VERSION}
+  if $eumm_version < 6.48;
+
+delete @WriteMakefileArgs{qw(META_ADD META_MERGE)}
+  if $eumm_version < 6.46;
+
+delete $WriteMakefileArgs{LICENSE}
+  if $eumm_version < 6.31;
+
+WriteMakefile(%WriteMakefileArgs);