Broadcast to linked actors error the cause of pausing

Author: pitr-ch

lib/concurrent/actor/behaviour.rb

@@ -199,9 +199,9 @@ def on_envelope(envelope)
           end
         end
 
-        def pause!
+        def pause!(error = nil)
           @paused = true
-          broadcast(:paused)
+          broadcast(error || :paused)
           true
         end
 
@@ -268,7 +268,7 @@ def on_envelope(envelope)
           when :terminate
             terminate!
           when :pause
-            behaviour!(Pausing).pause!
+            behaviour!(Pausing).pause!(error)
           else
             raise
           end
@@ -336,7 +336,7 @@ def on_envelope(envelope)
 
       class ErrorOnUnknownMessage < Abstract
         def on_envelope(envelope)
-          raise "unknown message #{envelope.message.inspect}"
+          raise UnknownMessage, envelope
         end
       end
 

lib/concurrent/actor/errors.rb

@@ -5,10 +5,23 @@ module Actor
     class ActorTerminated < Error
       include TypeCheck
 
+      attr_reader :reference
+
       def initialize(reference)
-        Type! reference, Reference
+        @reference = Type! reference, Reference
         super reference.path
       end
     end
+
+    class UnknownMessage < Error
+      include TypeCheck
+
+      attr_reader :envelope
+
+      def initialize(envelope)
+        @envelope = Type! envelope, Envelope
+        super envelope.message.inspect
+      end
+    end
   end
 end

spec/concurrent/actor_spec.rb

@@ -288,7 +288,7 @@ def on_message(message)
 
             -> m do
               queue << m
-              if m == :paused
+              if UnknownMessage === m
                 ivar = envelope.sender.ask(:add)
                 envelope.sender << :resume!
                 queue << ivar.value!
@@ -298,7 +298,7 @@ def on_message(message)
 
           expect(queue.pop).to eq :init
           expect(queue.pop).to eq test
-          expect(queue.pop).to eq :paused
+          expect(queue.pop).to be_kind_of(UnknownMessage)
           expect(queue.pop).to eq 1
           expect(queue.pop).to eq :resumed
           terminate_actors test
@@ -314,7 +314,7 @@ def on_message(message)
 
             -> m do
               queue << m
-              if m == :paused
+              if UnknownMessage === m
                 ivar = envelope.sender.ask(:add)
                 envelope.sender << :reset!
                 queue << ivar.value!
@@ -324,7 +324,7 @@ def on_message(message)
 
           expect(queue.pop).to eq :init
           expect(queue.pop).to eq test
-          expect(queue.pop).to eq :paused
+          expect(queue.pop).to be_kind_of(UnknownMessage)
           expect(queue.pop).to eq :init # rebuilds context
           expect(queue.pop).to eq 1
           expect(queue.pop).to eq :reset