Stop trying to configure listen by default on compatible platforms (rails#42985)

David Heinemeier Hansson · web-flow · commit e34300a921a9 · 2021-08-11T15:18:43.000+02:00
* Stop trying to configure listen by default on compatible platforms

Modern computers with SSDs don't see much/any benefit from having an evented file update watcher. Remove complexity by taking this spinning-drive concession out.

* Actually need listen for testing the opt-in

* Test no longer relevant
diff --git a/Gemfile.lock b/Gemfile.lock
@@ -294,7 +294,7 @@ GEM
       mustache
       nokogiri
     libxml-ruby (3.2.1)
-    listen (3.5.1)
+    listen (3.6.0)
       rb-fsevent (~> 0.10, >= 0.10.3)
       rb-inotify (~> 0.9, >= 0.9.10)
     loofah (2.10.0)
diff --git a/actionmailbox/test/dummy/config/environments/development.rb b/actionmailbox/test/dummy/config/environments/development.rb
@@ -63,8 +63,4 @@
 
   # Annotate rendered view with file names
   # config.action_view.annotate_rendered_view_with_filenames = true
-
-  # Use an evented file watcher to asynchronously detect changes in source code,
-  # routes, locales, etc. This feature depends on the listen gem.
-  # config.file_watcher = ActiveSupport::EventedFileUpdateChecker
 end
diff --git a/actiontext/test/dummy/config/environments/development.rb b/actiontext/test/dummy/config/environments/development.rb
@@ -63,8 +63,4 @@
 
   # Annotate rendered view with file names
   # config.action_view.annotate_rendered_view_with_filenames = true
-
-  # Use an evented file watcher to asynchronously detect changes in source code,
-  # routes, locales, etc. This feature depends on the listen gem.
-  # config.file_watcher = ActiveSupport::EventedFileUpdateChecker
 end
diff --git a/activestorage/test/dummy/config/environments/development.rb b/activestorage/test/dummy/config/environments/development.rb
@@ -48,8 +48,4 @@
 
   # Annotate rendered view with file names
   # config.action_view.annotate_rendered_view_with_filenames = true
-
-  # Use an evented file watcher to asynchronously detect changes in source code,
-  # routes, locales, etc. This feature depends on the listen gem.
-  # config.file_watcher = ActiveSupport::EventedFileUpdateChecker
 end
diff --git a/guides/source/command_line.md b/guides/source/command_line.md
@@ -105,7 +105,6 @@ If you wish to skip some files or components from being generated, you can appen
 | `--skip-action-cable`   | Skip Action Cable files                                     |
 | `--skip-sprockets`      | Skip Sprockets files                                        |
 | `--skip-spring`         | Don't install Spring application preloader                  |
-| `--skip-listen`         | Don't generate configuration that depends on the listen gem |
 | `--skip-javascript`     | Skip JavaScript files                                       |
 | `--skip-turbolinks`     | Skip turbolinks gem                                         |
 | `--skip-test`           | Skip test files                                             |
diff --git a/guides/source/getting_started.md b/guides/source/getting_started.md
@@ -184,8 +184,7 @@ install the gem dependencies that are already mentioned in `Gemfile` using
 
 NOTE: If you're using Windows Subsystem for Linux then there are currently some
 limitations on file system notifications that mean you should disable the `spring`
-and `listen` gems which you can do by running `rails new blog --skip-spring --skip-listen`
-instead.
+gem which you can do by running `rails new blog --skip-spring` instead.
 
 TIP: You can see all of the command line options that the Rails application
 generator accepts by running `rails new --help`.
diff --git a/railties/lib/rails/generators/app_base.rb b/railties/lib/rails/generators/app_base.rb
@@ -70,9 +70,6 @@ def self.add_shared_options_for(name)
         class_option :skip_spring,         type: :boolean, default: false,
                                            desc: "Don't install Spring application preloader"
 
-        class_option :skip_listen,         type: :boolean, default: false,
-                                           desc: "Don't generate configuration that depends on the listen gem"
-
         class_option :skip_javascript,     type: :boolean, aliases: "-J", default: name == "plugin",
                                            desc: "Skip JavaScript files"
 
@@ -417,18 +414,10 @@ def depends_on_system_test?
         !(options[:skip_system_test] || options[:skip_test] || options[:api])
       end
 
-      def depend_on_listen?
-        !options[:skip_listen] && os_supports_listen_out_of_the_box?
-      end
-
       def depend_on_bootsnap?
         !options[:skip_bootsnap] && !options[:dev] && !defined?(JRUBY_VERSION)
       end
 
-      def os_supports_listen_out_of_the_box?
-        /darwin|linux/.match?(RbConfig::CONFIG["host_os"])
-      end
-
       def run_bundle
         bundle_command("install", "BUNDLE_IGNORE_MESSAGES" => "1") if bundle_install?
       end
diff --git a/railties/lib/rails/generators/rails/app/templates/Gemfile.tt b/railties/lib/rails/generators/rails/app/templates/Gemfile.tt
@@ -55,9 +55,6 @@ group :development do
   # Note: Interferes with etag cache testing. Can be configured to work on production: https://github.com/MiniProfiler/rack-mini-profiler/blob/master/README.md
   # gem "rack-mini-profiler", "~> 2.0"
 <%- end -%>
-<% if depend_on_listen? -%>
-  gem "listen", "~> 3.3"
-<% end -%>
 <% if spring_install? -%>
   # Spring speeds up development by keeping your application running in the background. Read more: https://github.com/rails/spring
   gem "spring"
diff --git a/railties/lib/rails/generators/rails/app/templates/config/environments/development.rb.tt b/railties/lib/rails/generators/rails/app/templates/config/environments/development.rb.tt
@@ -72,10 +72,6 @@ Rails.application.configure do
   # Annotate rendered view with file names.
   # config.action_view.annotate_rendered_view_with_filenames = true
 
-  # Use an evented file watcher to asynchronously detect changes in source code,
-  # routes, locales, etc. This feature depends on the listen gem.
-  <%= "# " unless depend_on_listen? %>config.file_watcher = ActiveSupport::EventedFileUpdateChecker
-
   # Uncomment if you wish to allow Action Cable access from any origin.
   # config.action_cable.disable_request_forgery_protection = true
 end
diff --git a/railties/lib/rails/generators/rails/plugin/plugin_generator.rb b/railties/lib/rails/generators/rails/plugin/plugin_generator.rb
@@ -121,7 +121,6 @@ def generate_test_dummy(force = false)
       opts[:force] = force
       opts[:skip_bundle] = true
       opts[:skip_spring] = true
-      opts[:skip_listen] = true
       opts[:skip_git] = true
       opts[:skip_turbolinks] = true
       opts[:skip_webpack_install] = true
diff --git a/railties/test/generators/app_generator_test.rb b/railties/test/generators/app_generator_test.rb
@@ -744,46 +744,6 @@ def test_inclusion_of_a_debugger
     end
   end
 
-  def test_inclusion_of_listen_related_configuration_by_default
-    run_generator
-    if /darwin|linux/.match?(RbConfig::CONFIG["host_os"])
-      assert_listen_related_configuration
-    else
-      assert_no_listen_related_configuration
-    end
-  end
-
-  def test_inclusion_of_listen_related_configuration_on_other_rubies
-    ruby_engine = Object.send(:remove_const, :RUBY_ENGINE)
-    Object.const_set(:RUBY_ENGINE, "MyRuby")
-
-    run_generator
-    if /darwin|linux/.match?(RbConfig::CONFIG["host_os"])
-      assert_listen_related_configuration
-    else
-      assert_no_listen_related_configuration
-    end
-  ensure
-    Object.send(:remove_const, :RUBY_ENGINE)
-    Object.const_set(:RUBY_ENGINE, ruby_engine)
-  end
-
-  def test_non_inclusion_of_listen_related_configuration_if_skip_listen
-    run_generator [destination_root, "--skip-listen"]
-    assert_no_listen_related_configuration
-  end
-
-  def test_evented_file_update_checker_config
-    run_generator
-    assert_file "config/environments/development.rb" do |content|
-      if /darwin|linux/.match?(RbConfig::CONFIG["host_os"])
-        assert_match(/^\s*config\.file_watcher = ActiveSupport::EventedFileUpdateChecker/, content)
-      else
-        assert_match(/^\s*# config\.file_watcher = ActiveSupport::EventedFileUpdateChecker/, content)
-      end
-    end
-  end
-
   def test_template_from_dir_pwd
     FileUtils.cd(Rails.root)
     assert_match(/It works from file!/, run_generator([destination_root, "-m", "lib/template.rb"]))
@@ -1311,22 +1271,6 @@ def assert_no_gem(gem, app_path = ".")
       end
     end
 
-    def assert_listen_related_configuration
-      assert_gem "listen"
-
-      assert_file "config/environments/development.rb" do |content|
-        assert_match(/^\s*config\.file_watcher = ActiveSupport::EventedFileUpdateChecker/, content)
-      end
-    end
-
-    def assert_no_listen_related_configuration
-      assert_no_gem "listen"
-
-      assert_file "config/environments/development.rb" do |content|
-        assert_match(/^\s*# config\.file_watcher = ActiveSupport::EventedFileUpdateChecker/, content)
-      end
-    end
-
     def assert_webpack_installation_skipped(output)
       assert_match(/^Skipping `rails webpacker:install`/, output)
 
diff --git a/railties/test/generators/generators_test_helper.rb b/railties/test/generators/generators_test_helper.rb
@@ -94,7 +94,6 @@ def gemfile_locals
       {
         skip_active_storage: true,
         depend_on_bootsnap: false,
-        depend_on_listen: false,
         spring_install: false,
         depends_on_system_test: false,
         options: ActiveSupport::OrderedOptions.new,
diff --git a/railties/test/generators/plugin_generator_test.rb b/railties/test/generators/plugin_generator_test.rb
@@ -627,14 +627,6 @@ def test_dummy_application_uses_dynamic_rails_version_number
     end
   end
 
-  def test_dummy_application_skip_listen_by_default
-    run_generator
-
-    assert_file "test/dummy/config/environments/development.rb" do |contents|
-      assert_match(/^\s*# config\.file_watcher = ActiveSupport::EventedFileUpdateChecker/, contents)
-    end
-  end
-
   def test_ensure_that_gitignore_can_be_generated_from_a_template_for_dummy_path
     FileUtils.cd(Rails.root)
     run_generator([destination_root, "--dummy_path", "spec/dummy", "--skip-test"])
diff --git a/railties/test/isolation/abstract_unit.rb b/railties/test/isolation/abstract_unit.rb
@@ -511,7 +511,7 @@ def self.sh(cmd)
   FileUtils.rm_rf(app_template_path)
   FileUtils.mkdir_p(app_template_path)
 
-  sh "#{Gem.ruby} #{RAILS_FRAMEWORK_ROOT}/railties/exe/rails new #{app_template_path} --skip-bundle --skip-spring --skip-listen --no-rc --skip-webpack-install --quiet"
+  sh "#{Gem.ruby} #{RAILS_FRAMEWORK_ROOT}/railties/exe/rails new #{app_template_path} --skip-bundle --skip-spring --no-rc --skip-webpack-install --quiet"
   File.open("#{app_template_path}/config/boot.rb", "w") do |f|
     f.puts 'require "rails/all"'
   end
