[BUGFIX] Fix possible infinite blocking

Avoid cases where executing AGI commands (reported as sending SIP messages) might block indefinitely due to a race condition in fetching their response value.

Requires a fix to Celluloid: celluloid/celluloid#456

CHANGELOG.md

@@ -2,6 +2,7 @@
   * Bugfix: Prevent Asterisk translator death due to dead DTMF recognizers ([#221](https://github.com/adhearsion/punchblock/pull/221), [adhearsion/adhearsion#479](https://github.com/adhearsion/adhearsion/issues/479))
   * Bugfix: Be more intelligent about only stripping true file extensions off filenames for playback on Asterisk ([adhearsion/adhearsion#482](https://github.com/adhearsion/adhearsion/issues/482))
   * Bugfix: Handle a corner case crash where a recognition request is interrupted directly after a successful recognition has completed
+  * Bugfix: Avoid cases where executing AGI commands (reported as sending SIP messages) might block indefinitely due to a race condition in fetching their response value
 
 # [v2.5.2](https://github.com/adhearsion/punchblock/compare/v2.5.1...v2.5.2) - [2014-04-03](https://rubygems.org/gems/punchblock/versions/2.5.2)
   * Bugfix: No longer confound start and stop beeps on record commands (#220)

lib/punchblock/translator/asterisk/call.rb

@@ -254,12 +254,12 @@ def execute_command(command)
         # @raises RubyAMI::Error, ChannelGoneError
         def execute_agi_command(command, *params)
           agi = AGICommand.new Punchblock.new_uuid, channel, command, *params
-          condition = Celluloid::Condition.new
+          response = Celluloid::Future.new
           register_tmp_handler :ami, name: 'AsyncAGI', [:[], 'SubEvent'] => 'Exec', [:[], 'CommandID'] => agi.id do |event|
-            condition.signal event
+            response.signal Celluloid::SuccessResponse.new(nil, event)
           end
           agi.execute @ami_client
-          event = condition.wait
+          event = response.value
           return unless event
           agi.parse_result event
         end

spec/punchblock/translator/asterisk/call_spec.rb

@@ -1647,7 +1647,7 @@ def grxml_doc(mode = :dtmf)
           end
 
           it 'should send an appropriate AsyncAGI AMI action' do
-            expect_any_instance_of(Celluloid::Condition).to receive(:wait).and_return nil
+            expect_any_instance_of(Celluloid::Future).to receive(:value).and_return nil
             expect(ami_client).to receive(:send_action).once.with('AGI', 'Channel' => channel, 'Command' => 'EXEC ANSWER', 'CommandID' => Punchblock.new_uuid).and_return(response)
             subject.execute_agi_command 'EXEC ANSWER'
           end
@@ -1656,7 +1656,7 @@ def grxml_doc(mode = :dtmf)
             let(:params) { [1000, 'foo'] }
 
             it 'should send the appropriate action' do
-              expect_any_instance_of(Celluloid::Condition).to receive(:wait).and_return nil
+              expect_any_instance_of(Celluloid::Future).to receive(:value).and_return nil
               expect(ami_client).to receive(:send_action).once.with('AGI', 'Channel' => channel, 'Command' => 'WAIT FOR DIGIT "1000" "foo"', 'CommandID' => Punchblock.new_uuid).and_return(response)
               subject.execute_agi_command 'WAIT FOR DIGIT', *params
             end