Indicate if a shape is too_complex in ObjectSpace#dump

ext/objspace/objspace_dump.c

@@ -406,10 +406,8 @@ dump_object(VALUE obj, struct dump_config *dc)
     dump_append(dc, "\"");
 
     size_t shape_id = rb_shape_get_shape_id(obj);
-    if (shape_id) {
     dump_append(dc, ", \"shape_id\":");
     dump_append_sizet(dc, shape_id);
-    }
 
     dump_append(dc, ", \"slot_size\":");
     dump_append_sizet(dc, dc->cur_page_slot_size);
@@ -548,6 +546,9 @@ dump_object(VALUE obj, struct dump_config *dc)
       case T_OBJECT:
         dump_append(dc, ", \"ivars\":");
         dump_append_lu(dc, ROBJECT_IV_COUNT(obj));
+        if (rb_shape_obj_too_complex(obj)) {
+            dump_append(dc, ", \"too_complex_shape\":true");
+        }
         break;
 
       case T_FILE:

test/objspace/test_objspace.rb

@@ -272,6 +272,35 @@ class TestObjSpace < Test::Unit::TestCase
     JSON.parse(info) if defined?(JSON)
   end
 
+  def test_dump_too_complex_shape
+    if defined?(RubyVM::Shape)
+      RubyVM::Shape::SHAPE_MAX_VARIATIONS.times do
+        Object.new.instance_variable_set(:"@a#{_1}", 1)
+      end
+
+      tc = Object.new
+      tc.instance_variable_set(:@new_ivar, 1)
+      info = ObjectSpace.dump(tc)
+      assert_match(/"too_complex_shape":true/, info)
+      if defined?(JSON)
+        assert_true(JSON.parse(info)["too_complex_shape"])
+      end
+    end
+  end
+
+  class NotTooComplex ; end
+
+  def test_dump_not_too_complex_shape
+    tc = NotTooComplex.new
+    tc.instance_variable_set(:@new_ivar, 1)
+    info = ObjectSpace.dump(tc)
+
+    assert_not_match(/"too_complex_shape"/, info)
+    if defined?(JSON)
+      assert_nil(JSON.parse(info)["too_complex_shape"])
+    end
+  end
+
   def test_dump_to_default
     line = nil
     info = nil