Add specs for Marshal.dump and objects table

core/marshal/dump_spec.rb

@@ -47,6 +47,11 @@
         Marshal.dump(-2**31 - 1).should == "\x04\bl-\a\x01\x00\x00\x80"
       end
     end
+
+    it "does not use object links for objects repeatedly dumped" do
+      Marshal.dump([0, 0]).should == "\x04\b[\ai\x00i\x00"
+      Marshal.dump([2**16, 2**16]).should == "\x04\b[\ai\x03\x00\x00\x01i\x03\x00\x00\x01"
+    end
   end
 
   describe "with a Symbol" do
@@ -93,6 +98,11 @@
       value = [*value, value[0]]
       Marshal.dump(value).should == "\x04\b[\b#{symbol1}#{symbol2};\x00"
     end
+
+    it "uses symbol links for objects repeatedly dumped" do
+      symbol = :foo
+      Marshal.dump([symbol, symbol]).should == "\x04\b[\a:\bfoo;\x00" # ;\x00 is a link to the symbol object
+    end
   end
 
   describe "with an object responding to #marshal_dump" do
@@ -108,6 +118,20 @@
     it "raises TypeError if an Object is an instance of an anonymous class" do
       -> { Marshal.dump(Class.new(UserMarshal).new) }.should raise_error(TypeError, /can't dump anonymous class/)
     end
+
+    it "uses object links for objects repeatedly dumped" do
+      obj = UserMarshal.new
+      Marshal.dump([obj, obj]).should == "\x04\b[\aU:\x10UserMarshal:\tdata@\x06" # @\x06 is a link to the object
+    end
+
+    it "adds instance variables of a dumped object after the object itself into the objects table" do
+      value = "<foo>"
+      obj = MarshalSpec::UserMarshalDumpWithIvar.new("string", value)
+
+      # expect a link to the object (@\x06, that means Integer 1) is smaller than a link
+      # to the instance variable value (@\t, that means Integer 4)
+      Marshal.dump([obj, obj, value]).should == "\x04\b[\bU:)MarshalSpec::UserMarshalDumpWithIvarI[\x06\"\vstring\x06:\t@foo\"\n<foo>@\x06@\t"
+    end
   end
 
   describe "with an object responding to #_dump" do
@@ -166,6 +190,20 @@ def _dump(level)
       Marshal.dump([a, a]).should == "\x04\b[\aIu:\x17MarshalSpec::M1::A\v<dump>\x06:\t@foo\"\bbar#{reference}"
     end
 
+    it "uses object links for objects repeatedly dumped" do
+      obj = UserDefined.new
+      Marshal.dump([obj, obj]).should == "\x04\b[\au:\x10UserDefined\x12\x04\b[\a:\nstuff;\x00@\x06" # @\x06 is a link to the object
+    end
+
+    it "adds instance variables of a dumped String before the object itself into the objects table" do
+      value = "<foo>"
+      obj = MarshalSpec::UserDefinedDumpWithIVars.new(+"string", value)
+
+      # expect a link to the object (@\a, that means Integer 2) is greater than a link
+      # to the instance variable value (@\x06, that means Integer 1)
+      Marshal.dump([obj, obj, value]).should == "\x04\b[\bIu:*MarshalSpec::UserDefinedDumpWithIVars\vstring\x06:\t@foo\"\n<foo>@\a@\x06"
+    end
+
     describe "Core library classes with #_dump returning a String with instance variables" do
       it "indexes instance variables and then a Time object itself" do
         t = Time.utc(2022)
@@ -198,6 +236,10 @@ def _dump(level)
       Marshal.dump(source_object).should == "\x04\bc,MarshalSpec::Multibyte\xE3\x81\x81\xE3\x81\x82\xE3\x81\x83\xE3\x81\x84Class"
     end
 
+    it "uses object links for objects repeatedly dumped" do
+      Marshal.dump([String, String]).should == "\x04\b[\ac\vString@\x06" # @\x06 is a link to the object
+    end
+
     it "raises TypeError with an anonymous Class" do
       -> { Marshal.dump(Class.new) }.should raise_error(TypeError, /can't dump anonymous class/)
     end
@@ -221,6 +263,10 @@ def _dump(level)
       Marshal.dump(source_object).should == "\x04\bm-MarshalSpec::Multibyte\xE3\x81\x91\xE3\x81\x92\xE3\x81\x93\xE3\x81\x94Module"
     end
 
+    it "uses object links for objects repeatedly dumped" do
+      Marshal.dump([Marshal, Marshal]).should == "\x04\b[\am\fMarshal@\x06" # @\x06 is a link to the object
+    end
+
     it "raises TypeError with an anonymous Module" do
       -> { Marshal.dump(Module.new) }.should raise_error(TypeError, /can't dump anonymous module/)
     end
@@ -260,6 +306,11 @@ def _dump(level)
       ].should be_computed_by(:dump)
     end
 
+    it "uses object links for objects repeatedly dumped" do
+      n = 2**64
+      Marshal.dump([n, n]).should == "\x04\b[\al+\n\x00\x00\x00\x00\x00\x00\x00\x00\x01\x00@\x06" # @\x06 is a link to the object
+    end
+
     it "increases the object links counter" do
       obj = Object.new
       object_1_link = "\x06" # representing of (0-based) index=1 (by adding 5 for small Integers)
@@ -279,12 +330,22 @@ def _dump(level)
     it "dumps a Rational" do
       Marshal.dump(Rational(2, 3)).should == "\x04\bU:\rRational[\ai\ai\b"
     end
+
+    it "uses object links for objects repeatedly dumped" do
+      r = Rational(2, 3)
+      Marshal.dump([r, r]).should == "\x04\b[\aU:\rRational[\ai\ai\b@\x06" # @\x06 is a link to the object
+    end
   end
 
   describe "with a Complex" do
     it "dumps a Complex" do
       Marshal.dump(Complex(2, 3)).should == "\x04\bU:\fComplex[\ai\ai\b"
     end
+
+    it "uses object links for objects repeatedly dumped" do
+      c = Complex(2, 3)
+      Marshal.dump([c, c]).should == "\x04\b[\aU:\fComplex[\ai\ai\b@\x06" # @\x06 is a link to the object
+    end
   end
 
   ruby_version_is "3.2" do
@@ -303,6 +364,11 @@ def _dump(level)
         Marshal.dump(obj).should == "\x04\bS:5MarshalSpec::DataSpec::MeasureWithOverriddenName\a:\vamountii:\tunit\"\akm"
       end
 
+      it "uses object links for objects repeatedly dumped" do
+        d = MarshalSpec::DataSpec::Measure.new(100, 'km')
+        Marshal.dump([d, d]).should == "\x04\b[\aS:#MarshalSpec::DataSpec::Measure\a:\vamountii:\tunit\"\akm@\x06" # @\x06 is a link to the object
+      end
+
       it "raises TypeError with an anonymous Struct" do
         -> { Marshal.dump(Data.define(:a).new(1)) }.should raise_error(TypeError, /can't dump anonymous class/)
       end
@@ -364,6 +430,21 @@ def _dump(level)
     it "dumps multiple strings using symlinks for the :E (encoding) symbol" do
       Marshal.dump(["".encode("us-ascii"), "".encode("utf-8")]).should == "\x04\b[\aI\"\x00\x06:\x06EFI\"\x00\x06;\x00T"
     end
+
+    it "uses object links for objects repeatedly dumped" do
+      s = "string"
+      Marshal.dump([s, s]).should == "\x04\b[\a\"\vstring@\x06" # @\x06 is a link to the object
+    end
+
+    it "adds instance variables after the object itself into the objects table" do
+      obj = +"string"
+      value = "<foo>"
+      obj.instance_variable_set :@foo, value
+
+      # expect a link to the object (@\x06, that means Integer 1) is smaller than a link
+      # to the instance variable value (@\a, that means Integer 2)
+      Marshal.dump([obj, obj, value]).should == "\x04\b[\bI\"\vstring\x06:\t@foo\"\n<foo>@\x06@\a"
+    end
   end
 
   describe "with a Regexp" do
@@ -431,6 +512,11 @@ def _dump(level)
       obj = MarshalSpec::RegexpWithOverriddenName.new("")
       Marshal.dump(obj).should == "\x04\bIC:*MarshalSpec::RegexpWithOverriddenName/\x00\x00\x06:\x06EF"
     end
+
+    it "uses object links for objects repeatedly dumped" do
+      r = /\A.\Z/
+      Marshal.dump([r, r]).should == "\x04\b[\aI/\n\\A.\\Z\x00\x06:\x06EF@\x06" # @\x06 is a link to the object
+    end
   end
 
   describe "with an Array" do
@@ -466,6 +552,21 @@ def _dump(level)
       obj = MarshalSpec::ArrayWithOverriddenName.new
       Marshal.dump(obj).should == "\x04\bC:)MarshalSpec::ArrayWithOverriddenName[\x00"
     end
+
+    it "uses object links for objects repeatedly dumped" do
+      a = [1]
+      Marshal.dump([a, a]).should == "\x04\b[\a[\x06i\x06@\x06" # @\x06 is a link to the object
+    end
+
+    it "adds instance variables after the object itself into the objects table" do
+      obj = []
+      value = "<foo>"
+      obj.instance_variable_set :@foo, value
+
+      # expect a link to the object (@\x06, that means Integer 1) is smaller than a link
+      # to the instance variable value (@\a, that means Integer 2)
+      Marshal.dump([obj, obj, value]).should == "\x04\b[\bI[\x00\x06:\t@foo\"\n<foo>@\x06@\a"
+    end
   end
 
   describe "with a Hash" do
@@ -523,6 +624,21 @@ def _dump(level)
       obj = MarshalSpec::HashWithOverriddenName.new
       Marshal.dump(obj).should == "\x04\bC:(MarshalSpec::HashWithOverriddenName{\x00"
     end
+
+    it "uses object links for objects repeatedly dumped" do
+      h = {a: 1}
+      Marshal.dump([h, h]).should == "\x04\b[\a{\x06:\x06ai\x06@\x06" # @\x06 is a link to the object
+    end
+
+    it "adds instance variables after the object itself into the objects table" do
+      obj = {}
+      value = "<foo>"
+      obj.instance_variable_set :@foo, value
+
+      # expect a link to the object (@\x06, that means Integer 1) is smaller than a link
+      # to the instance variable value (@\a, that means Integer 2)
+      Marshal.dump([obj, obj, value]).should == "\x04\b[\bI{\x00\x06:\t@foo\"\n<foo>@\x06@\a"
+    end
   end
 
   describe "with a Struct" do
@@ -557,9 +673,24 @@ def _dump(level)
       Marshal.dump(obj).should == "\x04\bS:*MarshalSpec::StructWithOverriddenName\x06:\x06a\"\vmember"
     end
 
+    it "uses object links for objects repeatedly dumped" do
+      s = Struct::Pyramid.new
+      Marshal.dump([s, s]).should == "\x04\b[\aS:\x14Struct::Pyramid\x00@\x06" # @\x06 is a link to the object
+    end
+
     it "raises TypeError with an anonymous Struct" do
       -> { Marshal.dump(Struct.new(:a).new(1)) }.should raise_error(TypeError, /can't dump anonymous class/)
     end
+
+    it "adds instance variables after the object itself into the objects table" do
+      obj = Struct::Pyramid.new
+      value = "<foo>"
+      obj.instance_variable_set :@foo, value
+
+      # expect a link to the object (@\x06, that means Integer 1) is smaller than a link
+      # to the instance variable value (@\a, that means Integer 2)
+      Marshal.dump([obj, obj, value]).should == "\x04\b[\bIS:\x14Struct::Pyramid\x00\x06:\t@foo\"\n<foo>@\x06@\a"
+    end
   end
 
   describe "with an Object" do
@@ -649,6 +780,21 @@ def finalizer.noop(_)
       ObjectSpace.define_finalizer(obj, finalizer.method(:noop))
       Marshal.load(Marshal.dump(obj)).class.should == Object
     end
+
+    it "uses object links for objects repeatedly dumped" do
+      obj = Object.new
+      Marshal.dump([obj, obj]).should == "\x04\b[\ao:\vObject\x00@\x06" # @\x06 is a link to the object
+    end
+
+    it "adds instance variables after the object itself into the objects table" do
+      obj = Object.new
+      value = "<foo>"
+      obj.instance_variable_set :@foo, value
+
+      # expect a link to the object (@\x06, that means Integer 1) is smaller than a link
+      # to the instance variable value (@\a, that means Integer 2)
+      Marshal.dump([obj, obj, value]).should == "\x04\b[\bo:\vObject\x06:\t@foo\"\n<foo>@\x06@\a"
+    end
   end
 
   describe "with a Range" do
@@ -724,6 +870,26 @@ def finalizer.noop(_)
       Marshal.dump(source_object).should == "\x04\bc+MarshalSpec::Multibyte\xE3\x81\x81\xE3\x81\x82\xE3\x81\x83\xE3\x81\x84Time"
     end
 
+    it "uses object links for objects repeatedly dumped" do
+      # order of the offset and zone instance variables is a subject to change
+      # and may be different on different CRuby versions
+      base = Regexp.quote("\x04\b[\aIu:\tTime\r\xF5\xEF\e\x80\x00\x00\x00\x00\a")
+      offset = Regexp.quote(":\voffseti\x020*:\tzoneI\"\bAST\x06:\x06EF")
+      zone = Regexp.quote(":\tzoneI\"\bAST\x06:\x06EF:\voffseti\x020*")
+      instance_variables = /#{offset}|#{zone}/
+      Marshal.dump([@t, @t]).should =~ /\A#{base}#{instance_variables}@\a\Z/ # @\a is a link to the object
+    end
+
+    it "adds instance variables before the object itself into the objects table" do
+      obj = @utc
+      value = "<foo>"
+      obj.instance_variable_set :@foo, value
+
+      # expect a link to the object (@\b, that means Integer 3) is greater than a link
+      # to the instance variable value (@\x06, that means Integer 1)
+      Marshal.dump([obj, obj, value]).should == "\x04\b[\bIu:\tTime\r \x00\x1C\xC0\x00\x00\x00\x00\a:\t@foo\"\n<foo>:\tzoneI\"\bUTC\x06:\x06EF@\b@\x06"
+    end
+
     it "raises TypeError with an anonymous Time subclass" do
       -> { Marshal.dump(Class.new(Time).now) }.should raise_error(TypeError)
     end
@@ -778,6 +944,21 @@ def finalizer.noop(_)
       Marshal.dump(e).should =~ /undefined method [`']foo' for ("":String|an instance of String)/
     end
 
+    it "uses object links for objects repeatedly dumped" do
+      e = Exception.new
+      Marshal.dump([e, e]).should == "\x04\b[\ao:\x0EException\a:\tmesg0:\abt0@\x06" # @\x\a is a link to the object
+    end
+
+    it "adds instance variables after the object itself into the objects table" do
+      obj = Exception.new
+      value = "<foo>"
+      obj.instance_variable_set :@foo, value
+
+      # expect a link to the object (@\x06, that means Integer 1) is smaller than a link
+      # to the instance variable value (@\a, that means Integer 2)
+      Marshal.dump([obj, obj, value]).should == "\x04\b[\bo:\x0EException\b:\tmesg0:\abt0:\t@foo\"\n<foo>@\x06@\a"
+    end
+
     it "raises TypeError if an Object is an instance of an anonymous class" do
       anonymous_class = Class.new(Exception)
       obj = anonymous_class.new

core/marshal/fixtures/marshal_data.rb

@@ -97,6 +97,25 @@ def self._load(data)
   end
 end
 
+module MarshalSpec
+  class UserDefinedDumpWithIVars
+    attr_reader :string
+
+    def initialize(string, ivar_value)
+      @string = string
+      @string.instance_variable_set(:@foo, ivar_value)
+    end
+
+    def _dump(depth)
+      @string
+    end
+
+    def self._load(data)
+      new(data)
+    end
+  end
+end
+
 class UserPreviouslyDefinedWithInitializedIvar
   attr_accessor :field1, :field2
 end
@@ -139,6 +158,32 @@ def ==(other)
   end
 end
 
+module MarshalSpec
+  class UserMarshalDumpWithIvar
+    attr_reader :data
+
+    def initialize(data, ivar_value)
+      @data = data
+      @ivar_value = ivar_value
+    end
+
+    def marshal_dump
+      obj = [data]
+      obj.instance_variable_set(:@foo, @ivar_value)
+      obj
+    end
+
+    def marshal_load(o)
+      @data = o[0]
+    end
+
+    def ==(other)
+      self.class === other and
+        @data = other.data
+    end
+  end
+end
+
 class UserArray < Array
 end