From 27632d964704af70ca87507e525f820db77f9339 Mon Sep 17 00:00:00 2001
From: Samuel Williams <samuel.williams@oriontransfer.co.nz>
Date: Tue, 6 Feb 2024 23:55:35 +1300
Subject: [PATCH 1/2] Restart actor thread if it is killed/dies (e.g. on fork).

---
 lib/async/actor/proxy.rb | 41 ++++++++++++++++++++++++++++------------
 test/async/actor.rb      | 10 ++++++++++
 2 files changed, 39 insertions(+), 12 deletions(-)

diff --git a/lib/async/actor/proxy.rb b/lib/async/actor/proxy.rb
index 697950c..41fc575 100644
--- a/lib/async/actor/proxy.rb
+++ b/lib/async/actor/proxy.rb
@@ -25,15 +25,15 @@ def call(id)
 			def initialize(target)
 				@target = target
 				
-				@queue = ::Thread::Queue.new
-				@thread = __start__
-				
-				# Define a finalizer to ensure the thread is closed:
-				::ObjectSpace.define_finalizer(self, Finalizer.new(@queue, @thread))
+				@queue = nil
+				@thread = nil
+				@guard = ::Thread::Mutex.new
 			end
 			
 			# @parameter return_value [Symbol] One of :ignore, :promise or :wait.
 			def method_missing(*arguments, return_value: :wait, **options, &block)
+				__start__
+				
 				unless return_value == :ignore
 					result = Variable.new
 				end
@@ -49,18 +49,35 @@ def method_missing(*arguments, return_value: :wait, **options, &block)
 			
 			protected
 			
+			def __kill__
+				@queue&.close
+				@thread&.join
+			end
+			
 			def __start__
-				::Thread.new do
-					::Kernel.Sync do |task|
-						while operation = @queue.pop
-							task.async do
-								arguments, options, block, result = operation
-								Variable.fulfill(result) do
-									@target.public_send(*arguments, **options, &block)
+				return if @thread&.alive?
+				
+				@guard.synchronize do
+					return if @thread&.alive?
+					
+					@queue&.close
+					@queue = ::Thread::Queue.new
+					
+					@thread = ::Thread.new do
+						::Kernel.Sync do |task|
+							while operation = @queue.pop
+								task.async do
+									arguments, options, block, result = operation
+									Variable.fulfill(result) do
+										@target.public_send(*arguments, **options, &block)
+									end
 								end
 							end
 						end
 					end
+					
+					# Define a finalizer to ensure the thread is closed:
+					::ObjectSpace.define_finalizer(self, Finalizer.new(@queue, @thread))
 				end
 			end
 		end
diff --git a/test/async/actor.rb b/test/async/actor.rb
index 73cd6b9..698f75e 100644
--- a/test/async/actor.rb
+++ b/test/async/actor.rb
@@ -6,4 +6,14 @@
 		
 		expect(actor).to be_a(Array)
 	end
+	
+	it "can restart actor if thread is killed" do
+		actor = Async::Actor.new(Array.new)
+		
+		expect(actor).to be_a(Array)
+		
+		actor.__send__(:__kill__)
+		
+		expect(actor).to be_a(Array)
+	end
 end

From cc3f7bf3e45523ac2ca0194aa29f0cc4a61d8791 Mon Sep 17 00:00:00 2001
From: Samuel Williams <samuel.williams@oriontransfer.co.nz>
Date: Wed, 7 Feb 2024 00:07:20 +1300
Subject: [PATCH 2/2] Use guard to protect `__kill__` too.

---
 lib/async/actor/proxy.rb | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/lib/async/actor/proxy.rb b/lib/async/actor/proxy.rb
index 41fc575..c544da5 100644
--- a/lib/async/actor/proxy.rb
+++ b/lib/async/actor/proxy.rb
@@ -50,8 +50,13 @@ def method_missing(*arguments, return_value: :wait, **options, &block)
 			protected
 			
 			def __kill__
-				@queue&.close
-				@thread&.join
+				@guard.synchronize do
+					@queue&.close
+					@queue = nil
+					
+					@thread&.kill
+					@thread = nil
+				end
 			end
 			
 			def __start__