From da6e872fe9c00e77a9ee426e8fd46efec87bc38d Mon Sep 17 00:00:00 2001
From: Karen Etheridge <ether@cpan.org>
Date: Fri, 22 Jul 2016 11:23:20 -0700
Subject: [PATCH] ignore the backend variables when building perl core

Non-core backends are not yet installed, so we need to use CPAN::Meta::YAML
and JSON::PP.
---
 Changes                    |  5 +++++
 lib/Parse/CPAN/Meta.pm     | 12 +++++++++++-
 t/parse-cpan-meta/02_api.t | 31 ++++++++++++++++++-------------
 3 files changed, 34 insertions(+), 14 deletions(-)

diff --git a/Changes b/Changes
index e70b698..76e329a 100644
--- a/Changes
+++ b/Changes
@@ -2,6 +2,11 @@ Revision history for CPAN-Meta
 
 {{$NEXT}}
 
+  [FIXED]
+
+  - the YAML and JSON backend variables are ignored when building/testing the
+    perl core itself, where non-core backends are not yet installed.
+
   [CHANGED]
 
   - Added "use warnings" to Parse::CPAN::Meta
diff --git a/lib/Parse/CPAN/Meta.pm b/lib/Parse/CPAN/Meta.pm
index 6e23f9c..32fb7b3 100644
--- a/lib/Parse/CPAN/Meta.pm
+++ b/lib/Parse/CPAN/Meta.pm
@@ -60,7 +60,7 @@ sub load_json_string {
 }
 
 sub yaml_backend {
-  if (! defined $ENV{PERL_YAML_BACKEND} ) {
+  if ($ENV{PERL_CORE} or not defined $ENV{PERL_YAML_BACKEND} ) {
     _can_load( 'CPAN::Meta::YAML', 0.011 )
       or croak "CPAN::Meta::YAML 0.011 is not available\n";
     return "CPAN::Meta::YAML";
@@ -76,6 +76,11 @@ sub yaml_backend {
 }
 
 sub json_decoder {
+  if ($ENV{PERL_CORE}) {
+    _can_load( 'JSON::PP' => 2.27300 )
+      or croak "JSON::PP 2.27300 is not available\n";
+    return 'JSON::PP';
+  }
   if (my $decoder = $ENV{CPAN_META_JSON_DECODER}) {
     _can_load( $decoder )
       or croak "Could not load CPAN_META_JSON_DECODER '$decoder'\n";
@@ -87,6 +92,11 @@ sub json_decoder {
 }
 
 sub json_backend {
+  if ($ENV{PERL_CORE}) {
+    _can_load( 'JSON::PP' => 2.27300 )
+      or croak "JSON::PP 2.27300 is not available\n";
+    return 'JSON::PP';
+  }
   if (my $backend = $ENV{CPAN_META_JSON_BACKEND}) {
     _can_load( $backend )
       or croak "Could not load CPAN_META_JSON_BACKEND '$backend'\n";
diff --git a/t/parse-cpan-meta/02_api.t b/t/parse-cpan-meta/02_api.t
index 3f82fc4..c0ee52d 100644
--- a/t/parse-cpan-meta/02_api.t
+++ b/t/parse-cpan-meta/02_api.t
@@ -67,7 +67,7 @@ my $json_meta = catfile( test_data_directory(), 'json.meta' );
 
 ### YAML tests
 {
-  local $ENV{PERL_YAML_BACKEND}; # ensure we get CPAN::META::YAML
+  local $ENV{PERL_YAML_BACKEND} if not $ENV{PERL_CORE}; # ensure we always get CPAN::META::YAML
 
   is(Parse::CPAN::Meta->yaml_backend(), 'CPAN::Meta::YAML', 'yaml_backend(): CPAN::Meta::YAML');
   my $from_yaml = Parse::CPAN::Meta->load_file( $meta_yaml );
@@ -75,7 +75,7 @@ my $json_meta = catfile( test_data_directory(), 'json.meta' );
 }
 
 {
-  local $ENV{PERL_YAML_BACKEND}; # ensure we get CPAN::META::YAML
+  local $ENV{PERL_YAML_BACKEND} if not $ENV{PERL_CORE}; # ensure we always get CPAN::META::YAML
 
   note '';
   is(Parse::CPAN::Meta->yaml_backend(), 'CPAN::Meta::YAML', 'yaml_backend(): CPAN::Meta::YAML');
@@ -84,7 +84,7 @@ my $json_meta = catfile( test_data_directory(), 'json.meta' );
 }
 
 {
-  local $ENV{PERL_YAML_BACKEND}; # ensure we get CPAN::META::YAML
+  local $ENV{PERL_YAML_BACKEND} if not $ENV{PERL_CORE}; # ensure we always get CPAN::META::YAML
 
   note '';
   is(Parse::CPAN::Meta->yaml_backend(), 'CPAN::Meta::YAML', 'yaml_backend(): CPAN::Meta::YAML');
@@ -93,7 +93,7 @@ my $json_meta = catfile( test_data_directory(), 'json.meta' );
 }
 
 {
-  local $ENV{PERL_YAML_BACKEND}; # ensure we get CPAN::META::YAML
+  local $ENV{PERL_YAML_BACKEND} if not $ENV{PERL_CORE}; # ensure we always get CPAN::META::YAML
 
   note '';
   is(Parse::CPAN::Meta->yaml_backend(), 'CPAN::Meta::YAML', 'yaml_backend(): CPAN::Meta::YAML');
@@ -102,7 +102,7 @@ my $json_meta = catfile( test_data_directory(), 'json.meta' );
 }
 
 {
-  local $ENV{PERL_YAML_BACKEND}; # ensure we get CPAN::META::YAML
+  local $ENV{PERL_YAML_BACKEND} if not $ENV{PERL_CORE}; # ensure we always get CPAN::META::YAML
 
   note '';
   is(Parse::CPAN::Meta->yaml_backend(), 'CPAN::Meta::YAML', 'yaml_backend(): CPAN::Meta::YAML');
@@ -112,7 +112,7 @@ my $json_meta = catfile( test_data_directory(), 'json.meta' );
 }
 
 {
-  local $ENV{PERL_YAML_BACKEND}; # ensure we get CPAN::META::YAML
+  local $ENV{PERL_YAML_BACKEND} if not $ENV{PERL_CORE}; # ensure we always get CPAN::META::YAML
 
   note '';
   is(Parse::CPAN::Meta->yaml_backend(), 'CPAN::Meta::YAML', 'yaml_backend(): CPAN::Meta::YAML');
@@ -123,6 +123,7 @@ my $json_meta = catfile( test_data_directory(), 'json.meta' );
 
 SKIP: {
   note '';
+  skip 'these tests are for cpan builds only', 2 if $ENV{PERL_CORE};
   skip "YAML module not installed", 2
     unless eval "require YAML; 1";
   local $ENV{PERL_YAML_BACKEND} = 'YAML';
@@ -136,7 +137,7 @@ SKIP: {
 ### JSON tests
 {
   # JSON tests with JSON::PP
-  local $ENV{PERL_JSON_BACKEND}; # ensure we get JSON::PP
+  local $ENV{PERL_JSON_BACKEND} if not $ENV{PERL_CORE}; # ensure we always get JSON::PP
 
   note '';
   is(Parse::CPAN::Meta->json_backend(), 'JSON::PP', 'json_backend(): JSON::PP');
@@ -146,7 +147,7 @@ SKIP: {
 
 {
   # JSON tests with JSON::PP
-  local $ENV{PERL_JSON_BACKEND}; # ensure we get JSON::PP
+  local $ENV{PERL_JSON_BACKEND} if not $ENV{PERL_CORE}; # ensure we always get JSON::PP
 
   note '';
   is(Parse::CPAN::Meta->json_backend(), 'JSON::PP', 'json_backend(): JSON::PP');
@@ -156,7 +157,7 @@ SKIP: {
 
 {
   # JSON tests with JSON::PP
-  local $ENV{PERL_JSON_BACKEND}; # ensure we get JSON::PP
+  local $ENV{PERL_JSON_BACKEND} if not $ENV{PERL_CORE}; # ensure we always get JSON::PP
 
   note '';
   is(Parse::CPAN::Meta->json_backend(), 'JSON::PP', 'json_backend(): JSON::PP');
@@ -167,7 +168,7 @@ SKIP: {
 
 {
   # JSON tests with JSON::PP, take 2
-  local $ENV{PERL_JSON_BACKEND} = 0; # request JSON::PP
+  local $ENV{PERL_JSON_BACKEND} = 0 if not $ENV{PERL_CORE}; # request JSON::PP
 
   note '';
   is(Parse::CPAN::Meta->json_backend(), 'JSON::PP', 'json_backend(): JSON::PP');
@@ -178,7 +179,7 @@ SKIP: {
 
 {
   # JSON tests with JSON::PP, take 3
-  local $ENV{PERL_JSON_BACKEND} = 'JSON::PP'; # request JSON::PP
+  local $ENV{PERL_JSON_BACKEND} = 'JSON::PP' if not $ENV{PERL_CORE}; # request JSON::PP
 
   note '';
   is(Parse::CPAN::Meta->json_backend(), 'JSON::PP', 'json_backend(): JSON::PP');
@@ -187,14 +188,17 @@ SKIP: {
   is_deeply($from_json, $want, "load_json_string with PERL_JSON_BACKEND = 'JSON::PP'");
 }
 
-{
+SKIP: {
   # JSON tests with fake backend
+
+  note '';
+  skip 'these tests are for cpan builds only', 2 if $ENV{PERL_CORE};
+
   { package MyJSONThingy; $INC{'MyJSONThingy.pm'} = __FILE__; require JSON::PP;
     sub decode_json { JSON::PP::decode_json(@_) } }
 
   local $ENV{CPAN_META_JSON_DECODER} = 'MyJSONThingy'; # request fake backend
 
-  note '';
   is(Parse::CPAN::Meta->json_decoder(), 'MyJSONThingy', 'json_decoder(): MyJSONThingy');
   my $json   = load_ok( $meta_json, $meta_json, 100, ":encoding(UTF-8)");
   my $from_json = Parse::CPAN::Meta->load_json_string( $json );
@@ -203,6 +207,7 @@ SKIP: {
 
 SKIP: {
   note '';
+  skip 'these tests are for cpan builds only', 2 if $ENV{PERL_CORE};
   skip "JSON module version 2.5 not installed", 2
     unless eval "require JSON; JSON->VERSION(2.5); 1";
   local $ENV{PERL_JSON_BACKEND} = 1;