From 69743fbd85b659601174bff9fb61abc8c662c13b Mon Sep 17 00:00:00 2001
From: nahi <nahi@b2dd03c8-39d4-4d8f-98ff-823fe69b080e>
Date: Tue, 20 Oct 2009 16:14:25 +0000
Subject: [PATCH]         * lib/monitor.rb (MonitorMixin.mon_release): ensure
 the scheduled           thread to be alive when a thread is releasing a
 monitor. #2240

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/branches/ruby_1_8@25420 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
---
 ChangeLog                    |  5 +++++
 lib/monitor.rb               | 10 +++++++---
 test/monitor/test_monitor.rb | 29 +++++++++++++++++++++++++++++
 3 files changed, 41 insertions(+), 3 deletions(-)

diff --git a/ChangeLog b/ChangeLog
index 7ef14f5b2e..f472a11522 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+Wed Oct 21 01:19:56 2009  NAKAMURA, Hiroshi  <nahi@ruby-lang.org>
+
+	* lib/monitor.rb (MonitorMixin.mon_release): ensure the scheduled
+	  thread to be alive when a thread is releasing a monitor. #2240
+
 Wed Oct 21 00:28:52 2009  NAKAMURA, Hiroshi  <nahi@ruby-lang.org>
 
 	* lib/webrick/httpauth/digestauth.rb: typo in exception message fixed.
diff --git a/lib/monitor.rb b/lib/monitor.rb
index 4c146c8086..9158f9fb32 100644
--- a/lib/monitor.rb
+++ b/lib/monitor.rb
@@ -288,11 +288,15 @@ module MonitorMixin
     @mon_owner = Thread.current
   end
 
+  # mon_release requires Thread.critical == true
   def mon_release
     @mon_owner = nil
-    t = @mon_waiting_queue.shift
-    t = @mon_entering_queue.shift unless t
-    t.wakeup if t
+    while t = @mon_waiting_queue.shift || @mon_entering_queue.shift
+      if t.alive?
+        t.wakeup
+        return
+      end
+    end
   end
 
   def mon_enter_for_cond(count)
diff --git a/test/monitor/test_monitor.rb b/test/monitor/test_monitor.rb
index b539cb3cca..7593d3f938 100644
--- a/test/monitor/test_monitor.rb
+++ b/test/monitor/test_monitor.rb
@@ -54,6 +54,32 @@ class TestMonitor < Test::Unit::TestCase
     assert_equal((1..10).to_a, ary)
   end
 
+  def test_killed_thread_in_synchronize
+    ary = []
+    queue = Queue.new
+    t1 = Thread.start {
+      queue.pop
+      @monitor.synchronize {
+        ary << :t1
+      }
+    }
+    t2 = Thread.start {
+      queue.pop
+      @monitor.synchronize {
+        ary << :t2
+      }
+    }
+    @monitor.synchronize do
+      queue.enq(nil)
+      queue.enq(nil)
+      assert_equal([], ary)
+      t1.kill
+      t2.kill
+      ary << :main
+    end
+    assert_equal([:main], ary)
+  end
+
   def test_try_enter
     queue1 = Queue.new
     queue2 = Queue.new
@@ -94,7 +120,10 @@ class TestMonitor < Test::Unit::TestCase
       assert_equal(true, result1)
       assert_equal("bar", a)
     end
+  end
 
+  def test_timedwait
+    cond = @monitor.new_cond
     b = "foo"
     queue2 = Queue.new
     Thread.start do