* backport r32597 from trunk.

* thread.c (set_trace_func, thread_set_trace_func_m): reset tracing
  state when set_trace_func hook is removed.  This is workaround patch
  to force to reset tracing state that is broken by continuation call.
  a patch from James M. Lawrence.  [Feature #4347] [ruby-core:34998]

* test/ruby/test_continuation.rb (class TestContinuation): add a test
  for above.  a patch from James M. Lawrence.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/branches/ruby_1_9_3@32599 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

ChangeLog

@@ -1,3 +1,13 @@
+Thu Jul 21 20:02:11 2011  Yusuke Endoh  <mame@tsg.ne.jp>
+
+	* thread.c (set_trace_func, thread_set_trace_func_m): reset tracing
+	  state when set_trace_func hook is removed.  This is workaround patch
+	  to force to reset tracing state that is broken by continuation call.
+	  a patch from James M. Lawrence.  [Feature #4347] [ruby-core:34998]
+
+	* test/ruby/test_continuation.rb (class TestContinuation): add a test
+	  for above.  a patch from James M. Lawrence.
+
 Thu Jul 21 20:59:59 2011  Tanaka Akira  <akr@fsij.org>
 
 	* ext/socket/ancdata.c (discard_cmsg): workaround for MacOS X Lion.

test/ruby/test_continuation.rb

@@ -77,5 +77,48 @@ class TestContinuation < Test::Unit::TestCase
     }, '[ruby-dev:34802]'
   end
 
+  def tracing_with_set_trace_func
+    cont = nil
+    func = lambda do |*args|
+      @memo += 1
+      cont.call(nil)
+    end
+    cont = callcc { |cc| cc }
+    if cont
+      set_trace_func(func)
+    else
+      set_trace_func(nil)
+    end
+  end
+
+  def test_tracing_with_set_trace_func
+    @memo = 0
+    tracing_with_set_trace_func
+    tracing_with_set_trace_func
+    tracing_with_set_trace_func
+    assert_equal 3, @memo
+  end
+
+  def tracing_with_thread_set_trace_func
+    cont = nil
+    func = lambda do |*args|
+      @memo += 1
+      cont.call(nil)
+    end
+    cont = callcc { |cc| cc }
+    if cont
+      Thread.current.set_trace_func(func)
+    else
+      Thread.current.set_trace_func(nil)
+    end
+  end
+
+  def test_tracing_with_thread_set_trace_func
+    @memo = 0
+    tracing_with_thread_set_trace_func
+    tracing_with_thread_set_trace_func
+    tracing_with_thread_set_trace_func
+    assert_equal 3, @memo
+  end
 end
 

thread.c

@@ -4347,6 +4347,7 @@ set_trace_func(VALUE obj, VALUE trace)
     rb_remove_event_hook(call_trace_func);
 
     if (NIL_P(trace)) {
+	GET_THREAD()->tracing = EVENT_RUNNING_NOTHING;
 	return Qnil;
     }
 
@@ -4403,6 +4404,7 @@ thread_set_trace_func_m(VALUE obj, VALUE trace)
     rb_threadptr_remove_event_hook(th, call_trace_func);
 
     if (NIL_P(trace)) {
+	th->tracing = EVENT_RUNNING_NOTHING;
 	return Qnil;
     }
     thread_add_trace_func(th, trace);