Merge pull request #36803 from andrewkress/fix-issue-36799

read webpacker config to populate autoload paths

railties/lib/rails/engine/configuration.rb

@@ -1,20 +1,20 @@
 # frozen_string_literal: true
 
 require "rails/railtie/configuration"
-require "yaml"
 
 module Rails
   class Engine
     class Configuration < ::Rails::Railtie::Configuration
       attr_reader :root
-      attr_accessor :middleware
+      attr_accessor :middleware, :javascript_path
       attr_writer :eager_load_paths, :autoload_once_paths, :autoload_paths
 
       def initialize(root = nil)
         super()
         @root = root
         @generators = app_generators.dup
         @middleware = Rails::Configuration::MiddlewareStackProxy.new
+        @javascript_path = "javascript"
       end
 
       # Holds generators configuration:
@@ -41,7 +41,7 @@ def paths
 
           paths.add "app",                 eager_load: true,
                                            glob: "{*,*/concerns}",
-                                           exclude: ["assets", webpacker_path]
+                                           exclude: ["assets", javascript_path]
           paths.add "app/assets",          glob: "*"
           paths.add "app/controllers",     eager_load: true
           paths.add "app/channels",        eager_load: true, glob: "**/*_channel.rb"
@@ -86,14 +86,6 @@ def autoload_once_paths
       def autoload_paths
         @autoload_paths ||= paths.autoload_paths
       end
-
-      def webpacker_path
-        if File.file?("#{Rails.root}/config/webpacker.yml")
-          YAML.load_file("#{Rails.root}/config/webpacker.yml")[Rails.env]["source_path"]&.gsub("app/", "")
-        else
-          "javascript"
-        end
-      end
     end
   end
 end

railties/test/application/configuration_test.rb

@@ -1708,7 +1708,19 @@ def index
       app "development"
       ActiveSupport::Dependencies.autoload_paths.each do |path|
         assert_not_operator path, :ends_with?, "app/assets"
-        assert_not_operator path, :ends_with?, "app/#{Rails.configuration.webpacker_path}"
+        assert_not_operator path, :ends_with?, "app/javascript"
+      end
+    end
+
+    test "autoload paths will exclude the configured javascript_path" do
+      add_to_config "config.javascript_path = 'webpack'"
+      app_dir("app/webpack")
+
+      app "development"
+
+      ActiveSupport::Dependencies.autoload_paths.each do |path|
+        assert_not_operator path, :ends_with?, "app/assets"
+        assert_not_operator path, :ends_with?, "app/webpack"
       end
     end
 

railties/test/isolation/assets/config/webpacker.yml

@@ -1,4 +1,5 @@
 default: &default
+  source_path: app/javascript
   check_yarn_integrity: false
 development:
   <<: *default