Guide: ensure barrier is in scope (#253)

olleolleolle · web-flow · commit c1f9d32db06c · 2023-06-19T17:56:14.000+09:00
This change avoids a NoMethodError on the barrier local variable. And also a LoadError, with the Async::Barrier constant.
diff --git a/guides/best-practices/readme.md b/guides/best-practices/readme.md
@@ -32,16 +32,17 @@ A barrier ensures you don't leak tasks and that all tasks are completed or stopp
 
 ```ruby
 require 'async'
+require 'async/barrier'
 
 class Packages
 	def initialize(urls)
 		@urls = urls
 	end
 	
 	def fetch
-		Sync do
-			barrier = Async::Barrier.new
+		barrier = Async::Barrier.new
 			
+		Sync do
 			@urls.map do |url|
 				barrier.async do
 					fetch(url)
@@ -60,6 +61,7 @@ Unbounded concurrency is a common source of bugs. Use a semaphore to limit the n
 
 ```ruby
 require 'async'
+require 'async/barrier'
 require 'async/semaphore'
 
 class Packages
@@ -68,8 +70,9 @@ class Packages
 	end
 	
 	def fetch
+		barrier = Async::Barrier.new
+
 		Sync do
-			barrier = Async::Barrier.new
 			# Only 10 tasks are created at a time:
 			semaphore = Async::Semaphore.new(10, parent: barrier)
 			
