Merge pull request #5731 from heartcombo/fix-without-mailer-load

Fix Zeitwerk autoloading when ActionMailer is not present.

CHANGELOG.md

@@ -19,5 +19,8 @@
   * Add Rails 8 support.
     - Routes are lazy-loaded by default in test and development environments now so Devise loads them before `Devise.mappings` call.
 
+* bug fixes
+  * Make `Devise` work without `ActionMailer` when `Zeitwerk` autoloader is used.
+
 Please check [4-stable](https://github.com/heartcombo/devise/blob/4-stable/CHANGELOG.md)
 for previous changes.

lib/devise/rails.rb

@@ -47,5 +47,11 @@ class Engine < ::Rails::Engine
           )
         end
     end
+
+    initializer "devise.configure_zeitwerk" do
+      if Rails.autoloaders.zeitwerk_enabled? && !defined?(ActionMailer)
+        Rails.autoloaders.main.ignore("#{root}/app/mailers/devise/mailer.rb")
+      end
+    end
   end
 end