[ruby/psych] Refactor `symbolize_names`

https://github.com/ruby/psych/commit/3e472ab2d7

ext/psych/lib/psych.rb

@@ -276,8 +276,7 @@ module Psych
 
     result = parse(yaml, filename: filename)
     return fallback unless result
-    result = result.to_ruby if result
-    symbolize_names!(result) if symbolize_names
+    result = result.to_ruby(symbolize_names: symbolize_names) if result
     result
   end
 
@@ -353,12 +352,11 @@ module Psych
                                                permitted_symbols.map(&:to_s))
     scanner      = ScalarScanner.new class_loader
     visitor = if aliases
-                Visitors::ToRuby.new scanner, class_loader
+                Visitors::ToRuby.new scanner, class_loader, symbolize_names: symbolize_names
               else
-                Visitors::NoAliasRuby.new scanner, class_loader
+                Visitors::NoAliasRuby.new scanner, class_loader, symbolize_names: symbolize_names
               end
     result = visitor.accept result
-    symbolize_names!(result) if symbolize_names
     result
   end
 
@@ -604,19 +602,6 @@ module Psych
     @dump_tags[klass] = tag
   end
 
-  def self.symbolize_names!(result)
-    case result
-    when Hash
-      result.keys.each do |key|
-        result[key.to_sym] = symbolize_names!(result.delete(key))
-      end
-    when Array
-      result.map! { |r| symbolize_names!(r) }
-    end
-    result
-  end
-  private_class_method :symbolize_names!
-
   # Workaround for emulating `warn '...', uplevel: 1` in Ruby 2.4 or lower.
   def self.warn_with_uplevel(message, uplevel: 1)
     at = parse_caller(caller[uplevel]).join(':')

ext/psych/lib/psych/nodes/node.rb

@@ -46,8 +46,8 @@ module Psych
       # Convert this node to Ruby.
       #
       # See also Psych::Visitors::ToRuby
-      def to_ruby
-        Visitors::ToRuby.create.accept(self)
+      def to_ruby(symbolize_names: false)
+        Visitors::ToRuby.create(symbolize_names: symbolize_names).accept(self)
       end
       alias :transform :to_ruby
 

ext/psych/lib/psych/visitors/to_ruby.rb

@@ -12,20 +12,21 @@ module Psych
     ###
     # This class walks a YAML AST, converting each node to Ruby
     class ToRuby < Psych::Visitors::Visitor
-      def self.create
+      def self.create(symbolize_names: false)
         class_loader = ClassLoader.new
         scanner      = ScalarScanner.new class_loader
-        new(scanner, class_loader)
+        new(scanner, class_loader, symbolize_names: symbolize_names)
       end
 
       attr_reader :class_loader
 
-      def initialize ss, class_loader
+      def initialize ss, class_loader, symbolize_names: false
         super()
         @st = {}
         @ss = ss
         @domain_types = Psych.domain_types
         @class_loader = class_loader
+        @symbolize_names = symbolize_names
       end
 
       def accept target
@@ -336,7 +337,12 @@ module Psych
       SHOVEL = '<<'
       def revive_hash hash, o
         o.children.each_slice(2) { |k,v|
-          key = deduplicate(accept(k))
+          key = accept(k)
+          if @symbolize_names
+            key = key.to_sym
+          else
+            key = deduplicate(key)
+          end
           val = accept(v)
 
           if key == SHOVEL && k.tag != "tag:yaml.org,2002:str"