Add support for Sync(annotation:). (#348)

gems.rb

@@ -20,7 +20,7 @@
 end
 
 group :test do
-	gem "sus", "~> 0.29", ">= 0.29.1"
+	gem "sus", "~> 0.31"
 	gem "covered"
 	gem "decode"
 	gem "rubocop"

lib/kernel/sync.rb

@@ -15,17 +15,21 @@ module Kernel
 	#
 	# @public Since `stable-v1`.
 	# @asynchronous Will block until given block completes executing.
-	def Sync(&block)
+	def Sync(annotation: nil, &block)
 		if task = ::Async::Task.current?
-			yield task
+			if annotation
+				task.annotate(annotation) {yield task}
+			else
+				yield task
+			end
 		elsif scheduler = Fiber.scheduler
 			::Async::Task.run(scheduler, &block).wait
 		else
 			# This calls Fiber.set_scheduler(self):
 			reactor = Async::Reactor.new
 
 			begin
-				return reactor.run(finished: ::Async::Condition.new, &block).wait
+				return reactor.run(annotation: annotation, finished: ::Async::Condition.new, &block).wait
 			ensure
 				Fiber.set_scheduler(nil)
 			end

test/kernel/async.rb

@@ -17,6 +17,10 @@
 			Async(transient: true) do |task|
 				expect(task).to be(:transient?)
 			end
+
+			Async(annotation: 'foobar') do |task|
+				expect(task.annotation).to be == 'foobar'
+			end
 		end
 	end
 end

test/kernel/sync.rb

@@ -21,19 +21,45 @@
 
 			expect(result).to be == value
 		end
-
+
+		it "passes annotation through to initial task" do
+			Sync(annotation: 'foobar') do |task|
+				expect(task.annotation).to be == 'foobar'
+			end
+		end
+
 		it "can run inside reactor" do
 			Async do |task|
 				result = Sync do |sync_task|
 					expect(Async::Task.current).to be == task
 					expect(sync_task).to be == task
-					
+
 					next value
 				end
-				
+
 				expect(result).to be == value
 			end
 		end
+
+		with "parent task" do
+			it "replaces and restores existing task's annotation" do
+				annotations = []
+
+				Async(annotation: "foo") do |t1|
+					annotations << t1.annotation
+
+					Sync(annotation: "bar") do |t2|
+						expect(t2).to be_equal(t1)
+						annotations << t1.annotation
+					end
+
+					annotations << t1.annotation
+				end.wait
+
+				expect(annotations).to be == %w[foo bar foo]
+			end
+		end
+
 
 		it "can propagate error without logging them" do
 			expect(Console).not.to receive(:error)