From 2aaca105058950af2fc1a39c7e5c7cb032c85fff Mon Sep 17 00:00:00 2001
From: nobu <nobu@b2dd03c8-39d4-4d8f-98ff-823fe69b080e>
Date: Fri, 3 Feb 2017 06:23:34 +0000
Subject: [PATCH] eval.c: hide internal objects

* eval.c (rb_ensure): veil internal exception objects not to leak
  in ensure functions.  [ruby-core:79371] [Bug #13176]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@57510 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
---
 eval.c                                         |  5 ++++-
 ext/-test-/exception/ensured.c                 | 14 ++++++++++++++
 .../exception/test_exception_at_throwing.rb    | 18 ++++++++++++++++++
 3 files changed, 36 insertions(+), 1 deletion(-)
 create mode 100644 test/-ext-/exception/test_exception_at_throwing.rb

diff --git a/eval.c b/eval.c
index e16d59b8bb..8a839ced7d 100644
--- a/eval.c
+++ b/eval.c
@@ -924,7 +924,7 @@ rb_ensure(VALUE (*b_proc)(ANYARGS), VALUE data1, VALUE (*e_proc)(ANYARGS), VALUE
 {
     int state;
     volatile VALUE result = Qnil;
-    volatile VALUE errinfo;
+    VALUE errinfo;
     rb_thread_t *const th = GET_THREAD();
     rb_ensure_list_t ensure_list;
     ensure_list.entry.marker = 0;
@@ -938,6 +938,9 @@ rb_ensure(VALUE (*b_proc)(ANYARGS), VALUE data1, VALUE (*e_proc)(ANYARGS), VALUE
     }
     TH_POP_TAG();
     errinfo = th->errinfo;
+    if (!NIL_P(errinfo) && !RB_TYPE_P(errinfo, T_OBJECT)) {
+	th->errinfo = Qnil;
+    }
     th->ensure_list=ensure_list.next;
     (*ensure_list.entry.e_proc)(ensure_list.entry.data2);
     th->errinfo = errinfo;
diff --git a/ext/-test-/exception/ensured.c b/ext/-test-/exception/ensured.c
index 365e1f4f79..20423fd4c9 100644
--- a/ext/-test-/exception/ensured.c
+++ b/ext/-test-/exception/ensured.c
@@ -18,8 +18,22 @@ ensured(VALUE module, VALUE object)
     return rb_ensure(begin, object, ensure, object);
 }
 
+static VALUE
+raise(VALUE exc)
+{
+    rb_exc_raise(exc);
+    return Qnil;
+}
+
+static VALUE
+ensure_raise(VALUE module, VALUE object, VALUE exc)
+{
+    return rb_ensure(rb_yield, object, raise, exc);
+}
+
 void
 Init_ensured(VALUE klass)
 {
     rb_define_module_function(klass, "ensured", ensured, 1);
+    rb_define_module_function(klass, "ensure_raise", ensure_raise, 2);
 }
diff --git a/test/-ext-/exception/test_exception_at_throwing.rb b/test/-ext-/exception/test_exception_at_throwing.rb
new file mode 100644
index 0000000000..aba26079eb
--- /dev/null
+++ b/test/-ext-/exception/test_exception_at_throwing.rb
@@ -0,0 +1,18 @@
+# frozen_string_literal: true
+require 'test/unit'
+
+module Bug
+  class TestException < Test::Unit::TestCase
+    def test_exception_at_throwing
+      assert_separately(%w[-r-test-/exception], "#{<<-"begin;"}\n#{<<-"end;"}")
+      begin;
+        e = RuntimeError.new("[Bug #13176]")
+        assert_raise_with_message(e.class, e.message) do
+          catch do |t|
+            Bug::Exception.ensure_raise(nil, e) {throw t}
+          end
+        end
+      end;
+    end
+  end
+end