Inject Rails' channel paths in engine.

We were explicitly referencing Rails.root in ActionCable::Server::Configuration.initialize,
thereby coupling ourselves to Rails.

Instead add `app/channels` to Rails' app paths and assign the existent files
to `channel_paths`.

Users can still append to those load paths with `<<` and `push` in `config/application.rb`.

This means we can remove the custom `Dir` lookup in `channel_paths` and the Rails
and root definitions in the tests.

1 files changed, 2 insertions, 9 deletions

diff --git a/actioncable/lib/action_cable/server/configuration.rb b/actioncable/lib/action_cable/server/configuration.rb
index 9a248933c4..019a374734 100644
--- a/actioncable/lib/action_cable/server/configuration.rb
+++ b/actioncable/lib/action_cable/server/configuration.rb
@@ -5,27 +5,20 @@ module ActionCable
     class Configuration
       attr_accessor :logger, :log_tags
       attr_accessor :connection_class, :worker_pool_size
-      attr_accessor :channel_load_paths
       attr_accessor :disable_request_forgery_protection, :allowed_request_origins
       attr_accessor :cable, :url
 
+      attr_accessor :channel_paths # :nodoc:
+
       def initialize
         @log_tags = []
 
         @connection_class  = ApplicationCable::Connection
         @worker_pool_size  = 100
 
-        @channel_load_paths = [Rails.root.join('app/channels')]
-
         @disable_request_forgery_protection = false
       end
 
-      def channel_paths
-        @channel_paths ||= channel_load_paths.flat_map do |path|
-          Dir["#{path}/**/*_channel.rb"]
-        end
-      end
-
       def channel_class_names
         @channel_class_names ||= channel_paths.collect do |channel_path|
           Pathname.new(channel_path).basename.to_s.split('.').first.camelize