From 06dd20f7fe384f69ba4210c929e43a95c215ffa4 Mon Sep 17 00:00:00 2001
From: eregon <eregon@b2dd03c8-39d4-4d8f-98ff-823fe69b080e>
Date: Tue, 10 May 2016 12:46:43 +0000
Subject: [PATCH] * insns.def (defineclass): Also raise an error when
 redeclaring the   superclass of a class as Object and it has another
 superclass.   [Bug #12367] [ruby-core:75446] * test/ruby/test_class.rb: test
 for above.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@54970 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
---
 ChangeLog               |  8 ++++++++
 insns.def               |  9 ++++-----
 test/ruby/test_class.rb | 19 +++++++++++++++++++
 3 files changed, 31 insertions(+), 5 deletions(-)

diff --git a/ChangeLog b/ChangeLog
index c0e2de06cb..11b0a742ac 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,11 @@
+Tue May 10 21:05:45 2016  Benoit Daloze  <eregontp@gmail.com>
+
+	* insns.def (defineclass): Also raise an error when redeclaring the
+	  superclass of a class as Object and it has another superclass.
+	  [Bug #12367] [ruby-core:75446]
+
+	* test/ruby/test_class.rb: test for above.
+
 Tue May 10 14:57:09 2016  Nobuyoshi Nakada  <nobu@ruby-lang.org>
 
 	* random.c (obj_random_bytes): base on bytes method instead of
diff --git a/insns.def b/insns.def
index d34a66342c..ae7f98fa03 100644
--- a/insns.def
+++ b/insns.def
@@ -865,10 +865,6 @@ defineclass
 		     rb_obj_class(super));
 	}
 
-	if (super == Qnil) {
-	    super = rb_cObject;
-	}
-
 	vm_check_if_namespace(cbase);
 
 	/* find klass */
@@ -881,7 +877,7 @@ defineclass
 		rb_raise(rb_eTypeError, "%"PRIsVALUE" is not a class", rb_id2str(id));
 	    }
 
-	    if (super != rb_cObject) {
+	    if (VM_DEFINECLASS_HAS_SUPERCLASS_P(flags)) {
 		VALUE tmp;
 		tmp = rb_class_real(RCLASS_SUPER(klass));
 
@@ -892,6 +888,9 @@ defineclass
 	    }
 	}
 	else {
+	    if (!VM_DEFINECLASS_HAS_SUPERCLASS_P(flags)) {
+		super = rb_cObject;
+	    }
 	    /* new class declaration */
 	    klass = rb_define_class_id(id, super);
 	    rb_set_class_path_string(klass, cbase, rb_id2str(id));
diff --git a/test/ruby/test_class.rb b/test/ruby/test_class.rb
index 65f854d1ff..66a4059db7 100644
--- a/test/ruby/test_class.rb
+++ b/test/ruby/test_class.rb
@@ -378,6 +378,25 @@ class TestClass < Test::Unit::TestCase
     }
   end
 
+  define_method :test_invalid_reset_superclass do
+    class A; end
+    class SuperclassCannotBeReset < A
+    end
+    assert_equal A, SuperclassCannotBeReset.superclass
+
+    assert_raise_with_message(TypeError, /superclass mismatch/) {
+      class SuperclassCannotBeReset < String
+      end
+    }
+
+    assert_raise_with_message(TypeError, /superclass mismatch/, "[ruby-core:75446]") {
+      class SuperclassCannotBeReset < Object
+      end
+    }
+
+    assert_equal A, SuperclassCannotBeReset.superclass
+  end
+
   def test_cloned_singleton_method_added
     bug5283 = '[ruby-dev:44477]'
     added = []