class.c: cyclic prepend

* class.c (include_modules_at): detect cyclic prepend with original
  method table.  [ruby-core:52205] [Bug #7841]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@39236 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

1 files changed, 10 insertions, 0 deletions

diff --git a/test/ruby/test_module.rb b/test/ruby/test_module.rb
index 6fbf3af2e3..6b9ac4416b 100644
--- a/test/ruby/test_module.rb
+++ b/test/ruby/test_module.rb
@@ -1465,6 +1465,16 @@ class TestModule < Test::Unit::TestCase
     assert_equal([:m1], Class.new(Class.new{def m2;end}){ prepend Module.new; def m1; end }.instance_methods(false), bug6660)
   end
 
+  def test_cyclic_prepend
+    bug7841 = '[ruby-core:52205] [Bug #7841]'
+    m1 = Module.new
+    m2 = Module.new
+    m1.instance_eval { prepend(m2) }
+    assert_raise(ArgumentError, bug7841) do
+      m2.instance_eval { prepend(m1) }
+    end
+  end
+
   def test_class_variables
     m = Module.new
     m.class_variable_set(:@@foo, 1)