Logging thread should not die on logging errors.

railties/lib/rails/subscriber.rb

@@ -63,7 +63,11 @@ def self.dispatch(args)
       subscriber = subscribers[namespace.to_sym]
 
       if subscriber.respond_to?(name) && subscriber.logger
-        subscriber.send(name, ActiveSupport::Notifications::Event.new(*args))
+        begin
+          subscriber.send(name, ActiveSupport::Notifications::Event.new(*args))
+        rescue Exception => e
+          Rails.logger.error "Could not log #{args[0].inspect} event. #{e.class}: #{e.message}"
+        end
       end
 
       if args[0] == "action_dispatch.after_dispatch" && !subscribers.empty?

railties/test/subscriber_test.rb

@@ -18,6 +18,10 @@ def foo(event)
   def bar(event)
     info "#{color("cool", :red)}, #{color("isn't it?", :blue, true)}"
   end
+
+  def puke(event)
+    raise "puke"
+  end
 end
 
 module SubscriberTest
@@ -105,6 +109,16 @@ def test_flushes_the_same_logger_just_once
     assert_equal 1, @logger.flush_count
   end
 
+  def test_logging_thread_does_not_die_on_failures
+    Rails::Subscriber.add :my_subscriber, @subscriber
+    instrument "my_subscriber.puke"
+    instrument "action_dispatch.after_dispatch"
+    wait
+    assert_equal 1, @logger.flush_count
+    assert_equal 1, @logger.logged(:error).size
+    assert_equal 'Could not log "my_subscriber.puke" event. RuntimeError: puke', @logger.logged(:error).last
+  end
+
   def test_tails_logs_when_action_dispatch_callback_is_received
     log_tailer = mock()
     log_tailer.expects(:tail!)