* gc.c (obj_free): doesn't free a method table if it doesn't

  exits. [ruby-dev:44436]
* test/ruby/test_gc.rb (class TestGc): added the test case for
  this issue.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@35827 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

ChangeLog

@@ -1,3 +1,10 @@
+Mon May 28 12:03:04 2012  Narihiro Nakamura  <[email protected]>
+
+	* gc.c (obj_free): doesn't free a method table if it doesn't
+	  exits. [ruby-dev:44436]
+	* test/ruby/test_gc.rb (class TestGc): added the test case for
+	  this issue.
+
 Sun May 27 23:37:48 2012  Koichi Sasada  <[email protected]>
 
 	* benchmark/bm_vm1_lvar_init.rb: added.

gc.c

@@ -2501,7 +2501,9 @@ obj_free(rb_objspace_t *objspace, VALUE obj)
       case T_MODULE:
       case T_CLASS:
 	rb_clear_cache_by_class((VALUE)obj);
-	rb_free_m_table(RCLASS_M_TBL(obj));
+        if (RCLASS_M_TBL(obj)) {
+            rb_free_m_table(RCLASS_M_TBL(obj));
+        }
 	if (RCLASS_IV_TBL(obj)) {
 	    st_free_table(RCLASS_IV_TBL(obj));
 	}

test/ruby/test_gc.rb

@@ -78,6 +78,20 @@ def obj.bar() raise "obj.foo is called, but this is obj.bar" end
     EOS
   end
 
+  def test_singleton_method_added
+    assert_in_out_err(%w[--disable-gems], <<-EOS, [], [], "[ruby-dev:44436]")
+      class BasicObject
+        def singleton_method_added(mid)
+          raise
+        end
+      end
+      b = proc {}
+      class << b; end
+      b.clone rescue nil
+      GC.start
+    EOS
+  end
+
   def test_gc_parameter
     env = {
       "RUBY_GC_MALLOC_LIMIT" => "60000000",