Merge pull request #41643 from etiennebarrie/engine-include_all_helpers

Nudge engines to be compatible with include_all_helpers

railties/lib/rails/generators/rails/plugin/plugin_generator.rb

@@ -141,6 +141,13 @@ module Rails
       if mountable?
         template "rails/routes.rb", "#{dummy_path}/config/routes.rb", force: true
       end
+      if engine? && !api?
+        insert_into_file "#{dummy_path}/config/application.rb", indent(<<~RUBY, 4), after: /^\s*config\.load_defaults.*\n/
+
+          # For compatibility with applications that use this config
+          config.action_controller.include_all_helpers = false
+        RUBY
+      end
     end
 
     def test_dummy_webpacker_assets

railties/test/generators/plugin_generator_test.rb

@@ -591,6 +591,34 @@ class PluginGeneratorTest < Rails::Generators::TestCase
     assert_file "test/dummy/config/application.rb", /^require "bukkits"/
   end
 
+  def test_dummy_application_sets_include_all_helpers_to_false_for_mountable
+    run_generator [destination_root, "--mountable"]
+
+    assert_file "test/dummy/config/application.rb", /^    config\.action_controller\.include_all_helpers = false$/
+  end
+
+  def test_dummy_application_sets_include_all_helpers_to_false_for_full
+    run_generator [destination_root, "--full"]
+
+    assert_file "test/dummy/config/application.rb", /include_all_helpers/
+  end
+
+  def test_dummy_application_does_not_set_include_all_helpers_for_regular
+    run_generator
+
+    assert_file "test/dummy/config/application.rb" do |content|
+      assert_no_match(/include_all_helpers/, content)
+    end
+  end
+
+  def test_dummy_application_does_not_set_include_all_helpers_for_api
+    run_generator [destination_root, "--mountable", "--api"]
+
+    assert_file "test/dummy/config/application.rb" do |content|
+      assert_no_match(/include_all_helpers/, content)
+    end
+  end
+
   def test_dummy_application_uses_dynamic_rails_version_number
     run_generator