Add `Style/RedundantFreeze` to remove redudant `.freeze`

Since Rails 6.0 will support Ruby 2.4.1 or higher
`# frozen_string_literal: true` magic comment is enough to make string object frozen.
This magic comment is enabled by `Style/FrozenStringLiteralComment` cop.

* Exclude these files not to auto correct false positive `Regexp#freeze`
 - 'actionpack/lib/action_dispatch/journey/router/utils.rb'
 - 'activerecord/lib/active_record/connection_adapters/sqlite3_adapter.rb'

It has been fixed by https://github.com/rubocop-hq/rubocop/pull/6333
Once the newer version of RuboCop released and available at Code Climate these exclude entries should be removed.

* Replace `String#freeze` with `String#-@` manually if explicit frozen string objects are required

 - 'actionpack/test/controller/test_case_test.rb'
 - 'activemodel/test/cases/type/string_test.rb'
 - 'activesupport/lib/active_support/core_ext/string/strip.rb'
 - 'activesupport/test/core_ext/string_ext_test.rb'
 - 'railties/test/generators/actions_test.rb'

3 files changed, 5 insertions, 5 deletions

diff --git a/actionpack/lib/action_dispatch/routing/mapper.rb b/actionpack/lib/action_dispatch/routing/mapper.rb
index 8b5a39dcaf..2f68cefa94 100644
--- a/actionpack/lib/action_dispatch/routing/mapper.rb
+++ b/actionpack/lib/action_dispatch/routing/mapper.rb
@@ -679,7 +679,7 @@ module ActionDispatch
 
             script_namer = ->(options) do
               prefix_options = options.slice(*_route.segment_keys)
-              prefix_options[:relative_url_root] = "".freeze
+              prefix_options[:relative_url_root] = ""
 
               if options[:_recall]
                 prefix_options.reverse_merge!(options[:_recall].slice(*_route.segment_keys))
diff --git a/actionpack/lib/action_dispatch/routing/polymorphic_routes.rb b/actionpack/lib/action_dispatch/routing/polymorphic_routes.rb
index e17ccaf986..4de5f9e2f7 100644
--- a/actionpack/lib/action_dispatch/routing/polymorphic_routes.rb
+++ b/actionpack/lib/action_dispatch/routing/polymorphic_routes.rb
@@ -181,8 +181,8 @@ module ActionDispatch
             CACHE[type].fetch(action) { build action, type }
           end
 
-          def self.url;  CACHE["url".freeze][nil]; end
-          def self.path; CACHE["path".freeze][nil]; end
+          def self.url;  CACHE["url"][nil]; end
+          def self.path; CACHE["path"][nil]; end
 
           def self.build(action, type)
             prefix = action ? "#{action}_" : ""
diff --git a/actionpack/lib/action_dispatch/routing/route_set.rb b/actionpack/lib/action_dispatch/routing/route_set.rb
index da4f285f61..dc97d4b89c 100644
--- a/actionpack/lib/action_dispatch/routing/route_set.rb
+++ b/actionpack/lib/action_dispatch/routing/route_set.rb
@@ -377,7 +377,7 @@ module ActionDispatch
         @prepend                    = []
         @disable_clear_and_finalize = false
         @finalized                  = false
-        @env_key                    = "ROUTES_#{object_id}_SCRIPT_NAME".freeze
+        @env_key                    = "ROUTES_#{object_id}_SCRIPT_NAME"
         @url_helpers                = nil
         @deferred_classes           = []
 
@@ -767,7 +767,7 @@ module ActionDispatch
         # Remove leading slashes from controllers
         def normalize_controller!
           if controller
-            if controller.start_with?("/".freeze)
+            if controller.start_with?("/")
               @options[:controller] = controller[1..-1]
             else
               @options[:controller] = controller