Use an st table for "too complex" objects

st tables will maintain insertion order so we can marshal dump / load
objects with instance variables in the same order they were set on that
particular instance

[ruby-core:112926] [Bug #19535]

Co-Authored-By: Jemma Issroff <[email protected]>

1 files changed, 21 insertions, 0 deletions

diff --git a/test/ruby/test_shapes.rb b/test/ruby/test_shapes.rb
index b1a2ba2f1b..9525167d65 100644
--- a/test/ruby/test_shapes.rb
+++ b/test/ruby/test_shapes.rb
@@ -3,6 +3,17 @@ require 'test/unit'
 
 # These test the functionality of object shapes
 class TestShapes < Test::Unit::TestCase
+  class IVOrder
+    def expected_ivs
+      %w{ @a @b @c @d @e @f @g @h @i @j @k }
+    end
+
+    def set_ivs
+      expected_ivs.each { instance_variable_set(_1, 1) }
+      self
+    end
+  end
+
   class ShapeOrder
     def initialize
       @b = :b # 5 => 6
@@ -80,6 +91,16 @@ class TestShapes < Test::Unit::TestCase
     refute_equal(shape1.id, shape2.id)
   end
 
+  def test_iv_order_correct_on_complex_objects
+    (RubyVM::Shape::SHAPE_MAX_VARIATIONS + 1).times {
+      IVOrder.new.instance_variable_set("@a#{_1}", 1)
+    }
+
+    obj = IVOrder.new
+    iv_list = obj.set_ivs.instance_variables
+    assert_equal obj.expected_ivs, iv_list.map(&:to_s)
+  end
+
   def test_too_complex
     ensure_complex