Feature/APPEALS-44512-Zeitwerk-auto-transition (#1738) (#1739)

* Update Caseflow-Commons for Zeitwerk

* Remove classic loading, added Zeitwerk loading options

* Added to_prepare's - Solves DW on autoloading initialized constants

* Added Zeitwerk initializer file

* Refactored bgs_errors.rb and bgs.rb

* Remove require statements

* Added Fakes and TestAuthStrategy modules

* Readded accidental require deletion

* Removed plural from CurrentUserLoadTests

* Refactored for One File One Constant

* Added Zeitwerk Rspec test

* Fix Rubocop setup - removed incorrect include setup

* Added custom Rubocop - Top Level Constatns Per File

* Rename and moved Zeitwerk spec for Caseflow parity

* Fixed custom cop spec file structure

* Zeitwerk spec comments addressed

* Refactored for Caseflow parity

* Renamed for consistency

* Safety require

* Safety require and to_prepare for BGS

* Added autoload/eagerload section

* Renamed for consistency

* Readded require so to_prepare could be removed

* Added rubocop_todo for temp ignore linter errors

* Required changes for .rubocop.yml to work

* Updated Rubocop todo with proper generation

* Unecessary ShellCommand removed

* Ignored TestAuthStrategy in autoloading - unneeded

* Update .rubocop.yml



* Update app/services/external_api/vbms_service.rb



* Add #{root} to config/application.rb



* Cosmetic Update config/initializers/shoryuken.rb



* Cosmetic Update config/initializers/shoryuken.rb



* Cosmetic Update config/initializers/shoryuken.rb



* Cosmetic Update lib/fakes/test_auth_strategy.rb



* Added after_initialize to prevent multiple subscribers on relead

* Added before_initialize so Error class is loaded before anything else

* ✏️ Fix typo in filename

* 🚚 Move spec file to proper location

* ♻️ Lexically order filters in .simplecov

* 🔧 Filter `lib/efolder/migration.rb` from simplecov coverage

* ⬆️ Update `caseflow-commons` dependecy

---------

Co-authored-by: AKeyframe <[email protected]>
Co-authored-by: Jeremy Croteau <[email protected]>
Co-authored-by: Jeremy Croteau <[email protected]>

.rubocop.yml

@@ -1,10 +1,11 @@
+inherit_from: .rubocop_todo.yml
+
+require:
+  - .rubocop/custom_cop/top_level_constants_per_file.rb
+
 AllCops:
   TargetRubyVersion: 2.5
   TargetRailsVersion: 5.1
-  Include:
-    - '**/config.ru'
-    - '**/Rakefile'
-    - '**/*.rake'
   Exclude:
     - 'bin/**/*'
     - 'db/**/*'
@@ -62,3 +63,11 @@ Style/TrailingCommaInArrayLiteral:
 
 Style/TrailingCommaInHashLiteral:
   Enabled: false
+
+CustomCop/TopLevelConstantsPerFile:
+  Enabled: true
+  Include:
+    - 'app/**/*'
+    - 'lib/**/*'
+  Exclude:
+    - '**/*[^.rb]' # exclude non-.rb files (ex: .rake files)

.rubocop/custom_cop/top_level_constants_per_file.rb

@@ -0,0 +1,28 @@
+module RuboCop
+  module CustomCop
+    class TopLevelConstantsPerFile < RuboCop::Cop::Cop
+      MSG = "Multiple top-level constants detected in one file. The autoloader expects one top-level constant per file."
+
+      def investigate(processed_source)
+        return unless processed_source
+
+        # If more than one top-level constant in the file, add offense on the second one
+        if top_level_constant_nodes.size > 1
+          add_offense(top_level_constant_nodes[1], message: MSG)
+        end
+      end
+
+      private
+
+      def top_level_constant_nodes
+        @top_level_constant_nodes ||=
+          processed_source.ast.each_node(:class, :module).select { |node| top_level_constant?(node) }
+      end
+
+      def top_level_constant?(node)
+        # node is not nested within a class or module node?
+        node.ancestors.none? { |ancestor| ancestor.class_type? || ancestor.module_type? }
+      end
+    end
+  end
+end