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'

6 files changed, 8 insertions, 8 deletions

diff --git a/activesupport/lib/active_support/xml_mini/jdom.rb b/activesupport/lib/active_support/xml_mini/jdom.rb
index 59c65db2d5..32fe6ade28 100644
--- a/activesupport/lib/active_support/xml_mini/jdom.rb
+++ b/activesupport/lib/active_support/xml_mini/jdom.rb
@@ -18,7 +18,7 @@ module ActiveSupport
   module XmlMini_JDOM #:nodoc:
     extend self
 
-    CONTENT_KEY = "__content__".freeze
+    CONTENT_KEY = "__content__"
 
     NODE_TYPE_NAMES = %w{ATTRIBUTE_NODE CDATA_SECTION_NODE COMMENT_NODE DOCUMENT_FRAGMENT_NODE
     DOCUMENT_NODE DOCUMENT_TYPE_NODE ELEMENT_NODE ENTITY_NODE ENTITY_REFERENCE_NODE NOTATION_NODE
diff --git a/activesupport/lib/active_support/xml_mini/libxml.rb b/activesupport/lib/active_support/xml_mini/libxml.rb
index 2a16932f03..c2e999ef6c 100644
--- a/activesupport/lib/active_support/xml_mini/libxml.rb
+++ b/activesupport/lib/active_support/xml_mini/libxml.rb
@@ -34,7 +34,7 @@ module LibXML #:nodoc:
     end
 
     module Node #:nodoc:
-      CONTENT_ROOT = "__content__".freeze
+      CONTENT_ROOT = "__content__"
 
       # Convert XML document to hash.
       #
diff --git a/activesupport/lib/active_support/xml_mini/libxmlsax.rb b/activesupport/lib/active_support/xml_mini/libxmlsax.rb
index a22a2c9cb7..ac8acdfc3c 100644
--- a/activesupport/lib/active_support/xml_mini/libxmlsax.rb
+++ b/activesupport/lib/active_support/xml_mini/libxmlsax.rb
@@ -13,8 +13,8 @@ module ActiveSupport
     class HashBuilder
       include LibXML::XML::SaxParser::Callbacks
 
-      CONTENT_KEY   = "__content__".freeze
-      HASH_SIZE_KEY = "__hash_size__".freeze
+      CONTENT_KEY   = "__content__"
+      HASH_SIZE_KEY = "__hash_size__"
 
       attr_reader :hash
 
diff --git a/activesupport/lib/active_support/xml_mini/nokogiri.rb b/activesupport/lib/active_support/xml_mini/nokogiri.rb
index 4762a759d6..f76513f48b 100644
--- a/activesupport/lib/active_support/xml_mini/nokogiri.rb
+++ b/activesupport/lib/active_support/xml_mini/nokogiri.rb
@@ -38,7 +38,7 @@ module ActiveSupport
       end
 
       module Node #:nodoc:
-        CONTENT_ROOT = "__content__".freeze
+        CONTENT_ROOT = "__content__"
 
         # Convert XML document to hash.
         #
diff --git a/activesupport/lib/active_support/xml_mini/nokogirisax.rb b/activesupport/lib/active_support/xml_mini/nokogirisax.rb
index 0bbb4e258a..55cd72e093 100644
--- a/activesupport/lib/active_support/xml_mini/nokogirisax.rb
+++ b/activesupport/lib/active_support/xml_mini/nokogirisax.rb
@@ -16,8 +16,8 @@ module ActiveSupport
     # Class that will build the hash while the XML document
     # is being parsed using SAX events.
     class HashBuilder < Nokogiri::XML::SAX::Document
-      CONTENT_KEY   = "__content__".freeze
-      HASH_SIZE_KEY = "__hash_size__".freeze
+      CONTENT_KEY   = "__content__"
+      HASH_SIZE_KEY = "__hash_size__"
 
       attr_reader :hash
 
diff --git a/activesupport/lib/active_support/xml_mini/rexml.rb b/activesupport/lib/active_support/xml_mini/rexml.rb
index 55a155d4ee..8d6e3af066 100644
--- a/activesupport/lib/active_support/xml_mini/rexml.rb
+++ b/activesupport/lib/active_support/xml_mini/rexml.rb
@@ -8,7 +8,7 @@ module ActiveSupport
   module XmlMini_REXML #:nodoc:
     extend self
 
-    CONTENT_KEY = "__content__".freeze
+    CONTENT_KEY = "__content__"
 
     # Parse an XML Document string or IO into a simple hash.
     #