Add support for ruby 3.2 Data objects

Author: nevans

lib/psych/class_loader.rb

@@ -6,6 +6,7 @@ module Psych
   class ClassLoader # :nodoc:
     BIG_DECIMAL = 'BigDecimal'
     COMPLEX     = 'Complex'
+    DATA        = 'Data'
     DATE        = 'Date'
     DATE_TIME   = 'DateTime'
     EXCEPTION   = 'Exception'

lib/psych/visitors/to_ruby.rb

@@ -198,6 +198,14 @@ def visit_Psych_Nodes_Mapping o
             s
           end
 
+        when /^!ruby\/data(?::(.*))?$/
+          data = register(o, resolve_class($1).allocate) if $1
+          members = {}
+          revive_data_members(members, o)
+          data ||= allocate_anon_data(o, members)
+          data.send(:initialize, **members)
+          data
+
         when /^!ruby\/object:?(.*)?$/
           name = $1 || 'Object'
 
@@ -341,6 +349,20 @@ def register_empty object
         list
       end
 
+      def allocate_anon_data node, members
+        klass = class_loader.data.define(*members.keys)
+        register(node, klass.allocate)
+      end
+
+      def revive_data_members hash, o
+        o.children.each_slice(2) do |k,v|
+          name  = accept(k)
+          value = accept(v)
+          hash[class_loader.symbolize(name)] = value
+        end
+        hash
+      end
+
       def revive_hash hash, o, tagged= false
         o.children.each_slice(2) { |k,v|
           key = accept(k)

lib/psych/visitors/yaml_tree.rb

@@ -162,6 +162,16 @@ def visit_Object o
 
       alias :visit_Delegator :visit_Object
 
+      def visit_Data o
+        tag = ['!ruby/data', o.class.name].compact.join(':')
+        register o, @emitter.start_mapping(nil, tag, false, Nodes::Mapping::BLOCK)
+        o.members.each do |member|
+          @emitter.scalar member.to_s, nil, nil, true, false, Nodes::Scalar::ANY
+          accept o.send member
+        end
+        @emitter.end_mapping
+      end
+
       def visit_Struct o
         tag = ['!ruby/struct', o.class.name].compact.join(':')
 

test/psych/test_object_references.rb

@@ -31,6 +31,10 @@ def test_struct_has_references
       assert_reference_trip Struct.new(:foo).new(1)
     end
 
+    def test_data_has_references
+      assert_reference_trip Data.define(:foo).new(1)
+    end
+
     def assert_reference_trip obj
       yml = Psych.dump([obj, obj])
       assert_match(/\*-?\d+/, yml)

test/psych/test_safe_load.rb

@@ -109,6 +109,35 @@ def test_anon_struct
       assert_raise(Psych::DisallowedClass) do
         Psych.safe_load(<<-eoyml, permitted_classes: [Symbol])
 --- !ruby/struct
+  foo: bar
+                      eoyml
+      end
+    end
+
+    D = Data.define(:d)
+    def test_data_depends_on_sym
+      assert_safe_cycle(D.new(nil), permitted_classes: [D, Symbol])
+      assert_raise(Psych::DisallowedClass) do
+        cycle D.new(nil), permitted_classes: [D]
+      end
+    end
+
+    def test_anon_data
+      assert Psych.safe_load(<<-eoyml, permitted_classes: [Data, Symbol])
+--- !ruby/data
+  foo: bar
+                      eoyml
+
+      assert_raise(Psych::DisallowedClass) do
+        Psych.safe_load(<<-eoyml, permitted_classes: [Data])
+--- !ruby/data
+  foo: bar
+                      eoyml
+      end
+
+      assert_raise(Psych::DisallowedClass) do
+        Psych.safe_load(<<-eoyml, permitted_classes: [Symbol])
+--- !ruby/data
   foo: bar
                       eoyml
       end

test/psych/test_yaml.rb

@@ -7,6 +7,7 @@
 # [ruby-core:01946]
 module Psych_Tests
     StructTest = Struct::new( :c )
+    DataTest   = Data.define( :c )
 end
 
 class Psych_Unit_Tests < Psych::TestCase
@@ -1066,6 +1067,42 @@ def test_ruby_struct
 
     end
 
+    def test_ruby_data
+        Object.remove_const :MyBookData if Object.const_defined?(:MyBookData)
+        # Ruby Data value objects
+        book_class = Data.define(:author, :title, :year, :isbn)
+        Object.const_set(:MyBookData, book_class)
+        assert_to_yaml(
+            [ book_class.new( "Yukihiro Matsumoto", "Ruby in a Nutshell", 2002, "0-596-00214-9" ),
+              book_class.new( [ 'Dave Thomas', 'Andy Hunt' ], "The Pickaxe", 2002,
+                book_class.new( "This should be the ISBN", "but I have more data here", 2002, "None" )
+              ) ], <<EOY
+- !ruby/data:MyBookData
+  author: Yukihiro Matsumoto
+  title: Ruby in a Nutshell
+  year: 2002
+  isbn: 0-596-00214-9
+- !ruby/data:MyBookData
+  author:
+    - Dave Thomas
+    - Andy Hunt
+  title: The Pickaxe
+  year: 2002
+  isbn: !ruby/data:MyBookData
+    author: This should be the ISBN
+    title: but I have more data here
+    year: 2002
+    isbn: None
+EOY
+        )
+
+        assert_to_yaml( Psych_Tests::DataTest.new( 123 ), <<EOY )
+--- !ruby/data:Psych_Tests::DataTest
+c: 123
+EOY
+
+    end
+
     def test_ruby_rational
         assert_to_yaml( Rational(1, 2), <<EOY )
 --- !ruby/object:Rational

test/psych/visitors/test_yaml_tree.rb

@@ -73,6 +73,24 @@ def test_override_method
         assert_equal s.method, obj.method
       end
 
+      D = Data.define(:foo)
+
+      def test_data
+        assert_cycle D.new('bar')
+      end
+
+      def test_data_anon
+        d = Data.define(:foo).new('bar')
+        obj =  Psych.unsafe_load(Psych.dump(d))
+        assert_equal d.foo, obj.foo
+      end
+
+      def test_data_override_method
+        d = Data.define(:method).new('override')
+        obj =  Psych.unsafe_load(Psych.dump(d))
+        assert_equal d.method, obj.method
+      end
+
       def test_exception
         ex = Exception.new 'foo'
         loaded = Psych.unsafe_load(Psych.dump(ex))