object.c: forbid uninitialized class

* object.c (rb_class_initialize): forbid inheriting uninitialized
  class.  another class tree not based on BasicObject cannot exist.
  [ruby-core:47148][Bug #6863]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@36714 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

1 files changed, 3 insertions, 0 deletions

diff --git a/object.c b/object.c
index b7e1b58c81..73f76fa753 100644
--- a/object.c
+++ b/object.c
@@ -1616,6 +1616,9 @@ rb_class_initialize(int argc, VALUE *argv, VALUE klass)
     else {
 	rb_scan_args(argc, argv, "01", &super);
 	rb_check_inheritable(super);
+	if (super != rb_cBasicObject && !RCLASS_SUPER(super)) {
+	    rb_raise(rb_eTypeError, "can't inherit uninitialized class");
+	}
     }
     RCLASS_SUPER(klass) = super;
     rb_make_metaclass(klass, RBASIC(super)->klass);