DEV: Use fewer threads when watching for SCSS changes (#12393)

lib/stylesheet/watcher.rb

@@ -27,67 +27,62 @@ module Stylesheet
     end
 
     def start
-
       Thread.new do
         begin
           while true
             worker_loop
           end
         rescue => e
-          STDERR.puts "CSS change notifier crashed #{e}"
+          STDERR.puts "CSS change notifier crashed \n#{e}"
           start
         end
       end
 
-      root = Rails.root.to_s
-
-      listener_opts = { ignore: /xxxx/ }
+      listener_opts = { ignore: /xxxx/, only: /\.(css|scss)$/ }
       listener_opts[:force_polling] = true if ENV['FORCE_POLLING']
 
-      @paths.each do |watch|
-        Thread.new do
-          begin
-            plugins_paths = Dir.glob("#{Rails.root}/plugins/*").map do |file|
-              if File.symlink?(file)
-                File.expand_path(File.readlink(file), "#{Rails.root}/plugins")
-              else
-                file
-              end
-            end.compact
-
-            listener = Listen.to("#{root}/#{watch}", listener_opts) do |modified, added, _|
-              paths = [modified, added].flatten
-              paths.compact!
-              paths.map! do |long|
-                plugin_name = nil
-                plugins_paths.each do |plugin_path|
-                  if long.include?("#{plugin_path}/")
-                    plugin_name = File.basename(plugin_path)
-                    break
-                  end
-                end
-
-                target = nil
-                target_match = long.match(/admin|desktop|mobile|publish/)
-                if target_match&.length
-                  target = target_match[0]
-                end
-
-                {
-                  basename: File.basename(long),
-                  target: target,
-                  plugin_name: plugin_name
-                }
-              end
-
-              process_change(paths)
+      Thread.new do
+        begin
+          plugins_paths = Dir.glob("#{Rails.root}/plugins/*").map do |file|
+            if File.symlink?(file)
+              File.expand_path(File.readlink(file), "#{Rails.root}/plugins")
+            else
+              file
             end
-          rescue => e
-            STDERR.puts "Failed to listen for CSS changes at: #{watch}\n#{e}"
+          end.compact
+
+          listener = Listen.to(*@paths, listener_opts) do |modified, added, _|
+            paths = [modified, added].flatten
+            paths.compact!
+            paths.map! do |long|
+              plugin_name = nil
+              plugins_paths.each do |plugin_path|
+                if long.include?("#{plugin_path}/")
+                  plugin_name = File.basename(plugin_path)
+                  break
+                end
+              end
+
+              target = nil
+              target_match = long.match(/admin|desktop|mobile|publish/)
+              if target_match&.length
+                target = target_match[0]
+              end
+
+              {
+                basename: File.basename(long),
+                target: target,
+                plugin_name: plugin_name
+              }
+            end
+
+            process_change(paths)
           end
-          listener.start
-          sleep
+        rescue => e
+          STDERR.puts "Failed to listen for CSS changes: \n#{e}"
         end
+        listener.start
+        sleep
       end
     end
 
@@ -138,9 +133,7 @@ module Stylesheet
 
     def process_change(paths)
       paths.each do |path|
-        if path[:basename] =~ /\.(css|scss)$/
-          @queue.push path
-        end
+        @queue.push path
       end
     end