Turn on performance based cops

Use attr_reader/attr_writer instead of methods

method is 12% slower

Use flat_map over map.flatten(1)

flatten is 66% slower

Use hash[]= instead of hash.merge! with single arguments

merge! is 166% slower

See https://github.com/rails/rails/pull/32337 for more conversation

5 files changed, 6 insertions, 18 deletions

diff --git a/railties/lib/rails/application.rb b/railties/lib/rails/application.rb
index e346d5cc3a..bc5cd230fc 100644
--- a/railties/lib/rails/application.rb
+++ b/railties/lib/rails/application.rb
@@ -373,9 +373,7 @@ module Rails
       @config ||= Application::Configuration.new(self.class.find_root(self.class.called_from))
     end
 
-    def config=(configuration) #:nodoc:
-      @config = configuration
-    end
+    attr_writer :config
 
     # Returns secrets added to config/secrets.yml.
     #
@@ -413,9 +411,7 @@ module Rails
       end
     end
 
-    def secrets=(secrets) #:nodoc:
-      @secrets = secrets
-    end
+    attr_writer :secrets
 
     # The secret_key_base is used as the input secret to the application's key generator, which in turn
     # is used to create all MessageVerifiers/MessageEncryptors, including the ones that sign and encrypt cookies.
diff --git a/railties/lib/rails/application/configuration.rb b/railties/lib/rails/application/configuration.rb
index bba573499d..9c54cc1f37 100644
--- a/railties/lib/rails/application/configuration.rb
+++ b/railties/lib/rails/application/configuration.rb
@@ -146,9 +146,7 @@ module Rails
         @debug_exception_response_format || :default
       end
 
-      def debug_exception_response_format=(value)
-        @debug_exception_response_format = value
-      end
+      attr_writer :debug_exception_response_format
 
       def paths
         @paths ||= begin
diff --git a/railties/lib/rails/configuration.rb b/railties/lib/rails/configuration.rb
index d3a54d9364..e8741a50ba 100644
--- a/railties/lib/rails/configuration.rb
+++ b/railties/lib/rails/configuration.rb
@@ -79,13 +79,7 @@ module Rails
       end
 
       protected
-        def operations
-          @operations
-        end
-
-        def delete_operations
-          @delete_operations
-        end
+        attr_reader :operations, :delete_operations
     end
 
     class Generators #:nodoc:
diff --git a/railties/lib/rails/generators.rb b/railties/lib/rails/generators.rb
index 2a41403557..ed672ae48e 100644
--- a/railties/lib/rails/generators.rb
+++ b/railties/lib/rails/generators.rb
@@ -126,7 +126,7 @@ module Rails
         )
 
         if ARGV.first == "mailer"
-          options[:rails].merge!(template_engine: :erb)
+          options[:rails][:template_engine] = :erb
         end
       end
 
diff --git a/railties/lib/rails/generators/actions.rb b/railties/lib/rails/generators/actions.rb
index d85bbfb03e..ae395708cb 100644
--- a/railties/lib/rails/generators/actions.rb
+++ b/railties/lib/rails/generators/actions.rb
@@ -298,7 +298,7 @@ module Rails
           sudo = options[:sudo] && !Gem.win_platform? ? "sudo " : ""
           config = { verbose: false }
 
-          config.merge!(capture: options[:capture]) if options[:capture]
+          config[:capture] = options[:capture] if options[:capture]
 
           in_root { run("#{sudo}#{extify(executor)} #{command} RAILS_ENV=#{env}", config) }
         end