From 98cc15ed1e9193e17fad6b87cccf8f8b5ade7801 Mon Sep 17 00:00:00 2001
From: Kenta Murata <mrkn@mrkn.jp>
Date: Sun, 20 Dec 2020 12:17:32 +0900
Subject: [PATCH] [json] Stop using prototype objects

---
 ext/json/generator/generator.c   |  7 ++----
 ext/json/lib/json/common.rb      | 21 ++++++++++-------
 test/json/json_generator_test.rb | 39 +++-----------------------------
 3 files changed, 18 insertions(+), 49 deletions(-)

diff --git a/ext/json/generator/generator.c b/ext/json/generator/generator.c
index 80d1ca7bf3..2e802c8ea4 100644
--- a/ext/json/generator/generator.c
+++ b/ext/json/generator/generator.c
@@ -15,8 +15,7 @@ static VALUE mJSON, mExt, mGenerator, cState, mGeneratorMethods, mObject,
 #endif
              mFloat, mString, mString_Extend,
              mTrueClass, mFalseClass, mNilClass, eGeneratorError,
-             eNestingError,
-             i_SAFE_STATE_PROTOTYPE;
+             eNestingError;
 
 static ID i_to_s, i_to_json, i_new, i_indent, i_space, i_space_before,
           i_object_nl, i_array_nl, i_max_nesting, i_allow_nan, i_ascii_only,
@@ -1166,8 +1165,7 @@ static VALUE cState_from_state_s(VALUE self, VALUE opts)
     } else if (rb_obj_is_kind_of(opts, rb_cHash)) {
         return rb_funcall(self, i_new, 1, opts);
     } else {
-        VALUE prototype = rb_const_get(mJSON, i_SAFE_STATE_PROTOTYPE);
-        return rb_funcall(prototype, i_dup, 0);
+        return rb_class_new_instance(0, NULL, cState);
     }
 }
 
@@ -1608,5 +1606,4 @@ void Init_generator(void)
     i_encoding = rb_intern("encoding");
     i_encode = rb_intern("encode");
 #endif
-    i_SAFE_STATE_PROTOTYPE = rb_intern("SAFE_STATE_PROTOTYPE");
 }
diff --git a/ext/json/lib/json/common.rb b/ext/json/lib/json/common.rb
index 111d70c332..c34fa61eb7 100644
--- a/ext/json/lib/json/common.rb
+++ b/ext/json/lib/json/common.rb
@@ -71,22 +71,27 @@ module JSON
       end
       self.state = generator::State
       const_set :State, self.state
-      const_set :SAFE_STATE_PROTOTYPE, State.new
-      const_set :FAST_STATE_PROTOTYPE, State.new(
+    ensure
+      $VERBOSE = old
+    end
+
+    def create_fast_state
+      State.new(
         :indent         => '',
         :space          => '',
         :object_nl      => "",
         :array_nl       => "",
         :max_nesting    => false
       )
-      const_set :PRETTY_STATE_PROTOTYPE, State.new(
+    end
+
+    def create_pretty_state
+      State.new(
         :indent         => '  ',
         :space          => ' ',
         :object_nl      => "\n",
         :array_nl       => "\n"
       )
-    ensure
-      $VERBOSE = old
     end
 
     # Returns the JSON generator module that is used by JSON. This is
@@ -276,7 +281,7 @@ module JSON
     if State === opts
       state, opts = opts, nil
     else
-      state = SAFE_STATE_PROTOTYPE.dup
+      state = State.new
     end
     if opts
       if opts.respond_to? :to_hash
@@ -315,7 +320,7 @@ module JSON
     if State === opts
       state, opts = opts, nil
     else
-      state = FAST_STATE_PROTOTYPE.dup
+      state = JSON.create_fast_state
     end
     if opts
       if opts.respond_to? :to_hash
@@ -370,7 +375,7 @@ module JSON
     if State === opts
       state, opts = opts, nil
     else
-      state = PRETTY_STATE_PROTOTYPE.dup
+      state = JSON.create_pretty_state
     end
     if opts
       if opts.respond_to? :to_hash
diff --git a/test/json/json_generator_test.rb b/test/json/json_generator_test.rb
index 2ecdc97298..5bafc3ead4 100644
--- a/test/json/json_generator_test.rb
+++ b/test/json/json_generator_test.rb
@@ -48,35 +48,6 @@ EOT
     $VERBOSE = v
   end
 
-  def test_remove_const_segv
-    stress = GC.stress
-    const = JSON::SAFE_STATE_PROTOTYPE.dup
-
-    bignum_too_long_to_embed_as_string = 1234567890123456789012345
-    expect = bignum_too_long_to_embed_as_string.to_s
-    GC.stress = true
-
-    10.times do |i|
-      tmp = bignum_too_long_to_embed_as_string.to_json
-      raise "'\#{expect}' is expected, but '\#{tmp}'" unless tmp == expect
-    end
-
-    silence do
-      JSON.const_set :SAFE_STATE_PROTOTYPE, nil
-    end
-
-    10.times do |i|
-      assert_raise TypeError do
-        bignum_too_long_to_embed_as_string.to_json
-      end
-    end
-  ensure
-    GC.stress = stress
-    silence do
-      JSON.const_set :SAFE_STATE_PROTOTYPE, const
-    end
-  end if JSON.const_defined?("Ext") && RUBY_ENGINE != 'jruby'
-
   def test_generate
     json = generate(@hash)
     assert_equal(parse(@json2), parse(json))
@@ -171,7 +142,7 @@ EOT
   end
 
   def test_pretty_state
-    state = PRETTY_STATE_PROTOTYPE.dup
+    state = JSON.create_pretty_state
     assert_equal({
       :allow_nan             => false,
       :array_nl              => "\n",
@@ -188,7 +159,7 @@ EOT
   end
 
   def test_safe_state
-    state = SAFE_STATE_PROTOTYPE.dup
+    state = JSON::State.new
     assert_equal({
       :allow_nan             => false,
       :array_nl              => "",
@@ -205,7 +176,7 @@ EOT
   end
 
   def test_fast_state
-    state = FAST_STATE_PROTOTYPE.dup
+    state = JSON.create_fast_state
     assert_equal({
       :allow_nan             => false,
       :array_nl              => "",
@@ -241,12 +212,8 @@ EOT
 
   def test_depth
     ary = []; ary << ary
-    assert_equal 0, JSON::SAFE_STATE_PROTOTYPE.depth
     assert_raise(JSON::NestingError) { generate(ary) }
-    assert_equal 0, JSON::SAFE_STATE_PROTOTYPE.depth
-    assert_equal 0, JSON::PRETTY_STATE_PROTOTYPE.depth
     assert_raise(JSON::NestingError) { JSON.pretty_generate(ary) }
-    assert_equal 0, JSON::PRETTY_STATE_PROTOTYPE.depth
     s = JSON.state.new
     assert_equal 0, s.depth
     assert_raise(JSON::NestingError) { ary.to_json(s) }