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'

2 files changed, 4 insertions, 4 deletions

diff --git a/activerecord/lib/active_record/attribute_methods/read.rb b/activerecord/lib/active_record/attribute_methods/read.rb
index 0f7bcba564..903fe86e04 100644
--- a/activerecord/lib/active_record/attribute_methods/read.rb
+++ b/activerecord/lib/active_record/attribute_methods/read.rb
@@ -27,7 +27,7 @@ module ActiveRecord
           # Making it frozen means that it doesn't get duped when used to
           # key the @attributes in read_attribute.
           def define_method_attribute(name)
-            safe_name = name.unpack1("h*".freeze)
+            safe_name = name.unpack1("h*")
             temp_method = "__temp__#{safe_name}"
 
             ActiveRecord::AttributeMethods::AttrNames.set_name_cache safe_name, name
@@ -59,7 +59,7 @@ module ActiveRecord
         end
 
         primary_key = self.class.primary_key
-        name = primary_key if name == "id".freeze && primary_key
+        name = primary_key if name == "id" && primary_key
         sync_with_transaction_state if name == primary_key
         _read_attribute(name, &block)
       end
diff --git a/activerecord/lib/active_record/attribute_methods/write.rb b/activerecord/lib/active_record/attribute_methods/write.rb
index c7521422bb..62743bc9d8 100644
--- a/activerecord/lib/active_record/attribute_methods/write.rb
+++ b/activerecord/lib/active_record/attribute_methods/write.rb
@@ -13,7 +13,7 @@ module ActiveRecord
         private
 
           def define_method_attribute=(name)
-            safe_name = name.unpack1("h*".freeze)
+            safe_name = name.unpack1("h*")
             ActiveRecord::AttributeMethods::AttrNames.set_name_cache safe_name, name
             sync_with_transaction_state = "sync_with_transaction_state" if name == primary_key
 
@@ -40,7 +40,7 @@ module ActiveRecord
         end
 
         primary_key = self.class.primary_key
-        name = primary_key if name == "id".freeze && primary_key
+        name = primary_key if name == "id" && primary_key
         sync_with_transaction_state if name == primary_key
         _write_attribute(name, value)
       end