Support Marshal.{dump,load} for core Set

This was missed when adding core Set, because it's handled
implicitly for T_OBJECT.

Keep marshal compatibility between core Set and stdlib Set,
so you can unmarshal core Set with stdlib Set and vice versa.

Co-authored-by: Nobuyoshi Nakada <nobu@ruby-lang.org>

1 files changed, 26 insertions, 0 deletions

diff --git a/test/ruby/test_set.rb b/test/ruby/test_set.rb
index 565946096e..fd3ac4d9b6 100644
--- a/test/ruby/test_set.rb
+++ b/test/ruby/test_set.rb
@@ -6,6 +6,32 @@ class TC_Set < Test::Unit::TestCase
   class Set2 < Set
   end
 
+  def test_marshal
+    set = Set[1, 2, 3]
+    mset = Marshal.load(Marshal.dump(set))
+    assert_equal(set, mset)
+    assert_equal(set.compare_by_identity?, mset.compare_by_identity?)
+
+    set.compare_by_identity
+    mset = Marshal.load(Marshal.dump(set))
+    assert_equal(set, mset)
+    assert_equal(set.compare_by_identity?, mset.compare_by_identity?)
+
+    set.instance_variable_set(:@a, 1)
+    mset = Marshal.load(Marshal.dump(set))
+    assert_equal(set, mset)
+    assert_equal(set.compare_by_identity?, mset.compare_by_identity?)
+    assert_equal(1, mset.instance_variable_get(:@a))
+
+    old_stdlib_set_data = "\x04\bo:\bSet\x06:\n@hash}\bi\x06Ti\aTi\bTF".b
+    set = Marshal.load(old_stdlib_set_data)
+    assert_equal(Set[1, 2, 3], set)
+
+    old_stdlib_set_cbi_data = "\x04\bo:\bSet\x06:\n@hashC:\tHash}\ai\x06Ti\aTF".b
+    set = Marshal.load(old_stdlib_set_cbi_data)
+    assert_equal(Set[1, 2].compare_by_identity, set)
+  end
+
   def test_aref
     assert_nothing_raised {
       Set[]