improves zeitwerk:check

railties/lib/rails/tasks/zeitwerk.rake

 # frozen_string_literal: true
 
-indent = " " * 2
-
-ensure_classic_mode = ->() do
-  if Rails.autoloaders.zeitwerk_enabled?
-    abort <<~EOS
-      Please, enable temporarily :classic mode:
-
-        # config/application.rb
-        config.autoloader = :classic
-
-      and try again. When all is good, you can delete that line.
-    EOS
+ensure_zeitwerk_mode = ->() do
+  unless Rails.autoloaders.zeitwerk_enabled?
+    abort "Please, enable :zeitwerk mode in config/application.rb and try again."
   end
 end
 
 eager_load = ->() do
-  Rails.configuration.eager_load_namespaces.each(&:eager_load!)
-end
-
-check_directory = ->(directory, parent, mismatches) do
-  Dir.foreach(directory) do |entry|
-    next if entry.start_with?(".")
-    next if parent == Object && entry == "concerns"
-
-    abspath = File.join(directory, entry)
-
-    if File.directory?(abspath) || abspath.end_with?(".rb")
-      print "."
-      cname = File.basename(abspath, ".rb").camelize.to_sym
-      if parent.const_defined?(cname, false)
-        if File.directory?(abspath)
-          check_directory[abspath, parent.const_get(cname), mismatches]
-        end
-      else
-        mismatches << [abspath, parent, cname]
-      end
-    end
-  end
-end
-
-report_mismatches = ->(mismatches) do
-  puts
-  rails_root_prefix_re = %r{\A#{Regexp.escape(Rails.root.to_path)}/}
-  mismatches.each do |abspath, parent, cname|
-    relpath = abspath.sub(rails_root_prefix_re, "")
-    cpath = parent == Object ? cname : "#{parent.name}::#{cname}"
-    puts indent + "Mismatch: Expected #{relpath} to define #{cpath}"
-  end
-  puts
-
-  puts <<~EOS
-    Please revise the reported mismatches. You can normally fix them by adding
-    acronyms to config/initializers/inflections.rb or renaming the constants.
-  EOS
+  puts "Hold on, I am eager loading the application."
+  Zeitwerk::Loader.eager_load_all
 end
 
 report_not_checked = ->(not_checked) do
@@ -64,51 +19,48 @@ report_not_checked = ->(not_checked) do
   EOS
   puts
 
-  not_checked.each { |dir| puts indent + dir }
+  not_checked.each { |dir| puts "  #{dir}" }
   puts
 
   puts <<~EOS
     You may verify them manually, or add them to config.eager_load_paths
     in config/application.rb and run zeitwerk:check again.
   EOS
+  puts
 end
 
-report = ->(mismatches, not_checked) do
-  puts
-  if mismatches.empty? && not_checked.empty?
-    puts "All is good!"
-    puts "Please, remember to delete `config.autoloader = :classic` from config/application.rb."
+report = ->(not_checked) do
+  if not_checked.any?
+    report_not_checked[not_checked]
+    puts "Otherwise, all is good!"
   else
-    report_mismatches[mismatches]   if mismatches.any?
-    report_not_checked[not_checked] if not_checked.any?
+    puts "All is good!"
   end
 end
 
 namespace :zeitwerk do
   desc "Checks project structure for Zeitwerk compatibility"
   task check: :environment do
-    ensure_classic_mode[]
-    eager_load[]
+    ensure_zeitwerk_mode[]
 
-    eager_load_paths = Rails.configuration.eager_load_namespaces.map do |eln|
-      if eln.respond_to?(:config)
-        eln.config.eager_load_paths.select do |elp|
-          Dir.exist?(elp)
-        end
+    begin
+      eager_load[]
+    rescue NameError => e
+      if e.message =~ /expected file .*? to define constant \S+/
+        abort $&.sub(/#{Regexp.escape(Rails.root.to_s)}./, "")
+      else
+        raise
       end
-    end.compact.flatten
-
-    mismatches = []
-
-    $stdout.sync = true
-    eager_load_paths.each do |eager_load_path|
-      check_directory[eager_load_path, Object, mismatches]
     end
 
+    eager_load_paths = Rails.configuration.eager_load_namespaces.map do |eln|
+      eln.config.eager_load_paths if eln.respond_to?(:config)
+    end.compact.flatten
+
     not_checked = ActiveSupport::Dependencies.autoload_paths - eager_load_paths
     not_checked.select! { |dir| Dir.exist?(dir) }
     not_checked.reject! { |dir| Dir.empty?(dir) }
 
-    report[mismatches, not_checked]
+    report[not_checked]
   end
 end