1 files changed, 34 insertions, 14 deletions
diff --git a/lib/psych.rb b/lib/psych.rb
index c3292d9..cedf0a4 100644
--- a/lib/psych.rb
+++ b/lib/psych.rb
@@ -233,9 +233,9 @@ require 'psych/class_loader'
 
 module Psych
   # The version of libyaml Psych is using
-  LIBYAML_VERSION = Psych.libyaml_version.join '.'
+  LIBYAML_VERSION = Psych.libyaml_version.join('.').freeze
   # Deprecation guard
-  NOT_GIVEN = Object.new
+  NOT_GIVEN = Object.new.freeze
   private_constant :NOT_GIVEN
 
   ###
@@ -595,28 +595,25 @@ module Psych
   end
 
   # :stopdoc:
-  @domain_types = {}
   def self.add_domain_type domain, type_tag, &block
     key = ['tag', domain, type_tag].join ':'
-    @domain_types[key] = [key, block]
-    @domain_types["tag:#{type_tag}"] = [key, block]
+    domain_types[key] = [key, block]
+    domain_types["tag:#{type_tag}"] = [key, block]
   end
 
   def self.add_builtin_type type_tag, &block
     domain = 'yaml.org,2002'
     key = ['tag', domain, type_tag].join ':'
-    @domain_types[key] = [key, block]
+    domain_types[key] = [key, block]
   end
 
   def self.remove_type type_tag
-    @domain_types.delete type_tag
+    domain_types.delete type_tag
   end
 
-  @load_tags = {}
-  @dump_tags = {}
   def self.add_tag tag, klass
-    @load_tags[tag] = klass.name
-    @dump_tags[klass] = tag
+    load_tags[tag] = klass.name
+    dump_tags[klass] = tag
   end
 
   # Workaround for emulating `warn '...', uplevel: 1` in Ruby 2.4 or lower.
@@ -635,9 +632,32 @@ module Psych
   private_class_method :warn_with_uplevel, :parse_caller
 
   class << self
-    attr_accessor :load_tags
-    attr_accessor :dump_tags
-    attr_accessor :domain_types
+    if defined?(Ractor)
+      require 'forwardable'
+      extend Forwardable
+
+      class Config
+        attr_accessor :load_tags, :dump_tags, :domain_types
+        def initialize
+          @load_tags = {}
+          @dump_tags = {}
+          @domain_types = {}
+        end
+      end
+
+      def config
+        Ractor.current[:PsychConfig] ||= Config.new
+      end
+
+      def_delegators :config, :load_tags, :dump_tags, :domain_types, :load_tags=, :dump_tags=, :domain_types=
+    else
+      attr_accessor :load_tags
+      attr_accessor :dump_tags
+      attr_accessor :domain_types
+    end
   end
+  self.load_tags = {}
+  self.dump_tags = {}
+  self.domain_types = {}
   # :startdoc:
 end