add [MetaJSON] to [@basic]

Changes

@@ -24,6 +24,8 @@ Revision history for {{$dist->name}}
           release test (thanks, Karen Etheridge)
         - all builds now result in a .build/latest symlink (thanks again,
           Karen)
+        - [MetaJSON] is now in [@Basic], with special handling to handle the
+          possibility that the plugin is loaded twice
 
 6.012     2018-04-21 10:20:21+02:00 Europe/Oslo
         - revert addition of Archive::Tar::Wrapper as a mandatory prereq (in

lib/Dist/Zilla/Plugin/MetaJSON.pm

@@ -8,6 +8,7 @@ use Moose::Util::TypeConstraints;
 
 use Dist::Zilla::Dialect;
 
+use List::Util 'first';
 use namespace::autoclean;
 
 =head1 DESCRIPTION
@@ -54,6 +55,13 @@ has version => (
 sub gather_files ($self) {
   my $zilla = $self->zilla;
 
+  # gracefully handle there being more than one of us (e.g. one via [@Basic])
+  if ((first { $_->isa(__PACKAGE__) } $self->zilla->plugins->@*) != $self) {
+    $self->log('doing nothing: another [MetaJSON] already ran');
+    $self->log('To remove this warning, remove [MetaJSON] from your dist.ini, **and** add ":version = 7.000" underneath [@Basic]');
+    return;
+  }
+
   require JSON::MaybeXS;
   require Dist::Zilla::File::FromCode;
   require CPAN::Meta::Converter;

lib/Dist/Zilla/PluginBundle/Basic.pm

@@ -14,6 +14,7 @@ sub configure ($self) {
     PruneCruft
     ManifestSkip
     MetaYAML
+    MetaJSON
     License
     Readme
     ExtraTests
@@ -45,6 +46,7 @@ It includes the following plugins with their default configuration:
 * L<Dist::Zilla::Plugin::PruneCruft>
 * L<Dist::Zilla::Plugin::ManifestSkip>
 * L<Dist::Zilla::Plugin::MetaYAML>
+* L<Dist::Zilla::Plugin::MetaJSON>
 * L<Dist::Zilla::Plugin::License>
 * L<Dist::Zilla::Plugin::Readme>
 * L<Dist::Zilla::Plugin::ExtraTests>

t/plugins/metajson.t

@@ -0,0 +1,36 @@
+use strict;
+use warnings;
+
+use Test::More 0.88;
+use Test::DZil;
+use Test::Fatal;
+use Path::Tiny;
+
+{
+  my $tzil = Builder->from_config(
+    { dist_root => 'does-not-exist' },
+    {
+      add_files => {
+        'source/dist.ini' => simple_ini(
+          '@Basic',
+          'MetaJSON',
+        ),
+      },
+    },
+  );
+
+  $tzil->chrome->logger->set_debug(1);
+  is(
+    exception { $tzil->build },
+    undef,
+    'build proceeds normally',
+  );
+
+  my $build_dir = path($tzil->tempdir)->child('build');
+  ok(-e $build_dir->child('META.json'), 'META.json was created successfully');
+
+  diag 'got log messages: ', explain $tzil->log_messages
+    if not Test::Builder->new->is_passing;
+}
+
+done_testing;