Delegate to Fiber#annotate where possible. (#241)

async.gemspec

@@ -22,6 +22,7 @@ Gem::Specification.new do |spec|
 	spec.add_dependency "console", "~> 1.10"
 	spec.add_dependency "io-event", "~> 1.1"
 	spec.add_dependency "timers", "~> 4.1"
+	spec.add_dependency "fiber-annotate"
 
 	spec.add_development_dependency "bake-test"
 	spec.add_development_dependency "bake-test-external"

lib/async/node.rb

@@ -5,6 +5,8 @@
 # Copyright, 2017, by Kent Gruber.
 # Copyright, 2022, by Shannon Skipper.
 
+require 'fiber/annotate'
+
 require_relative 'list'
 
 module Async
@@ -109,20 +111,27 @@ def transient?
 
 		def annotate(annotation)
 			if block_given?
-				previous_annotation = @annotation
-				@annotation = annotation
-				yield
-				@annotation = previous_annotation
+				begin
+					current_annotation = @annotation
+					@annotation = annotation
+					return yield
+				ensure
+					@annotation = current_annotation
+				end
 			else
 				@annotation = annotation
 			end
 		end
 
+		def annotation
+			@annotation
+		end
+
 		def description
 			@object_name ||= "#{self.class}:#{format '%#018x', object_id}#{@transient ? ' transient' : nil}"
 
-			if @annotation
-				"#{@object_name} #{@annotation}"
+			if annotation = self.annotation
+				"#{@object_name} #{annotation}"
 			elsif line = self.backtrace(0, 1)&.first
 				"#{@object_name} #{line}"
 			else

lib/async/task.rb

@@ -96,6 +96,22 @@ def backtrace(*arguments)
 			@fiber&.backtrace(*arguments)
 		end
 
+		def annotate(annotation, &block)
+			if @fiber
+				@fiber.annotate(annotation, &block)
+			else
+				super
+			end
+		end
+
+		def annotation
+			if @fiber
+				@fiber.annotation
+			else
+				super
+			end
+		end
+
 		def to_s
 			"\#<#{self.description} (#{@status})>"
 		end
@@ -309,7 +325,7 @@ def stop!
 		end
 
 		def schedule(&block)
-			@fiber = Fiber.new do
+			@fiber = Fiber.new(annotation: self.annotation) do
 				set!
 
 				begin

test/async/task.rb

@@ -17,6 +17,32 @@ def after
 		super
 	end
 
+	with '#annotate' do
+		it "can annotate the current task that has not started yet" do
+			task = Async::Task.new(reactor) do |task|
+				sleep
+			end
+
+			task.annotate("Hello World")
+
+			expect(task.annotation).to be == "Hello World"
+		end
+
+		it "can annotate the current task that has started" do
+			task = Async::Task.new(reactor) do |task|
+				task.annotate("Hello World")
+
+				sleep
+			end
+
+			expect(task.fiber).to be_nil
+
+			task.run
+
+			expect(task.fiber.annotation).to be == "Hello World"
+		end
+	end
+
 	with '.yield' do
 		it "can yield back to scheduler" do
 			state = nil