* cont.c (rb_fiber_resume): raise an "double resume" error when root

fiber is going to be resumed.  [ruby-dev:42523]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@29680 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

ChangeLog

@@ -1,3 +1,8 @@
+Thu Nov  4 02:04:25 2010  Yusuke Endoh  <mame@tsg.ne.jp>
+
+	* cont.c (rb_fiber_resume): raise an "double resume" error when root
+	  fiber is going to be resumed.  [ruby-dev:42523]
+
 Wed Nov  3 14:17:18 2010  Nobuyoshi Nakada  <nobu@ruby-lang.org>
 
 	* lib/ostruct.rb (OpenStruct#delete_field): also undefine

cont.c

@@ -1292,7 +1292,7 @@ rb_fiber_resume(VALUE fibval, int argc, VALUE *argv)
     rb_fiber_t *fib;
     GetFiberPtr(fibval, fib);
 
-    if (fib->prev != Qnil) {
+    if (fib->prev != Qnil || fib->cont.type == ROOT_FIBER_CONTEXT) {
 	rb_raise(rb_eFiberError, "double resume");
     }
 

test/ruby/test_fiber.rb

@@ -189,5 +189,13 @@ class TestFiber < Test::Unit::TestCase
       f1.transfer
     }, '[ruby-dev:40833]'
   end
+
+  def test_resume_root_fiber
+    assert_raise(FiberError) do
+      Thread.new do
+        Fiber.current.resume
+      end.join
+    end
+  end
 end