4 files changed, 29 insertions, 1 deletions
diff --git a/ChangeLog b/ChangeLog
index d90a4fdcad..43d3f13318 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+Tue Dec 27 20:39:28 2016  Nobuyoshi Nakada  <nobu@ruby-lang.org>
+
+	* eval.c (exc_setup_cause): always set cause of cause to get rid of
+	  circular references. [Bug #13043]
+
 Tue Dec 27 20:13:12 2016  Kazuki Yamaguchi  <k@rhe.jp>
 
 	* re.c (match_{names,hash,equal}): consider the case of RMatch::regexp
diff --git a/eval.c b/eval.c
index fbd28565ed..a8935ff7ce 100644
--- a/eval.c
+++ b/eval.c
@@ -468,6 +468,9 @@ exc_setup_cause(VALUE exc, VALUE cause)
 #endif
     if (!NIL_P(cause) && cause != exc) {
 	rb_ivar_set(exc, id_cause, cause);
+	if (!rb_ivar_defined(cause, id_cause)) {
+	    rb_ivar_set(cause, id_cause, Qnil);
+	}
     }
     return exc;
 }
diff --git a/test/ruby/test_exception.rb b/test/ruby/test_exception.rb
index 3268096463..0e0179fd5f 100644
--- a/test/ruby/test_exception.rb
+++ b/test/ruby/test_exception.rb
@@ -717,6 +717,26 @@ end.join
     assert_equal({}, e.arg, bug)
   end
 
+  def test_circular_cause
+    bug13043 = '[ruby-core:78688] [Bug #13043]'
+    begin
+      begin
+        raise "error 1"
+      ensure
+        orig_error = $!
+        begin
+          raise "error 2"
+        rescue => err
+          raise orig_error
+        end
+      end
+    rescue => x
+    end
+    assert_equal(orig_error, x)
+    assert_equal(orig_error, err.cause)
+    assert_nil(orig_error.cause, bug13043)
+  end
+
   def test_anonymous_message
     assert_in_out_err([], "raise Class.new(RuntimeError), 'foo'", [], /foo\n/)
   end
diff --git a/version.h b/version.h
index 2cbdf44576..124fe8a08d 100644
--- a/version.h
+++ b/version.h
@@ -1,6 +1,6 @@
 #define RUBY_VERSION "2.2.7"
 #define RUBY_RELEASE_DATE "2016-12-27"
-#define RUBY_PATCHLEVEL 412
+#define RUBY_PATCHLEVEL 413
 
 #define RUBY_RELEASE_YEAR 2016
 #define RUBY_RELEASE_MONTH 12