Revert "Merge pull request #27925 from robin850/hwia-removal"

Pointed out by @matthewd that the HWIA subclass changes the
AS scoped class and top-level HWIA hierarchies out from under
existing classes.

This reverts commit 71da39097b67114329be6d8db7fe6911124531af, reversing
changes made to 41c33bd4b2ec3f4a482e6030b6fda15091d81e4a.

4 files changed, 4 insertions, 49 deletions

diff --git a/activerecord/lib/active_record/attribute_methods/dirty.rb b/activerecord/lib/active_record/attribute_methods/dirty.rb
index 6aa414ba6b..31c1e687dc 100644
--- a/activerecord/lib/active_record/attribute_methods/dirty.rb
+++ b/activerecord/lib/active_record/attribute_methods/dirty.rb
@@ -50,7 +50,7 @@ module ActiveRecord
         super.tap do
           @previous_mutation_tracker = nil
           clear_mutation_trackers
-          @changed_attributes = ActiveSupport::HashWithIndifferentAccess.new
+          @changed_attributes = HashWithIndifferentAccess.new
         end
       end
 
@@ -70,13 +70,13 @@ module ActiveRecord
 
       def changes_applied
         @previous_mutation_tracker = mutation_tracker
-        @changed_attributes = ActiveSupport::HashWithIndifferentAccess.new
+        @changed_attributes = HashWithIndifferentAccess.new
         clear_mutation_trackers
       end
 
       def clear_changes_information
         @previous_mutation_tracker = nil
-        @changed_attributes = ActiveSupport::HashWithIndifferentAccess.new
+        @changed_attributes = HashWithIndifferentAccess.new
         forget_attribute_assignments
         clear_mutation_trackers
       end
diff --git a/activesupport/CHANGELOG.md b/activesupport/CHANGELOG.md
index 788ea88752..2fb7f29d73 100644
--- a/activesupport/CHANGELOG.md
+++ b/activesupport/CHANGELOG.md
@@ -1,9 +1,3 @@
-*   Deprecated the top level `HashWithIndifferentAccess` constant.
-
-    Only `ActiveSupport::HashWithIndifferentAccess` should be used now.
-
-    *Robin Dupret* (#27925)
-
 *   Deprecate `.halt_callback_chains_on_return_false`.
 
     *Rafael Mendonça França*
diff --git a/activesupport/lib/active_support/hash_with_indifferent_access.rb b/activesupport/lib/active_support/hash_with_indifferent_access.rb
index 8638667082..79e7feaf47 100644
--- a/activesupport/lib/active_support/hash_with_indifferent_access.rb
+++ b/activesupport/lib/active_support/hash_with_indifferent_access.rb
@@ -316,20 +316,4 @@ module ActiveSupport
   end
 end
 
-class HashWithIndifferentAccess < ActiveSupport::HashWithIndifferentAccess
-  def initialize(*)
-    ActiveSupport::Deprecation.warn "HashWithIndifferentAccess is deprecated!" \
-                                    "Use ActiveSupport::HashWithIndifferentAccess instead."
-    super
-  end
-
-  def self.inherited(*)
-    ActiveSupport::Deprecation.warn "HashWithIndifferentAccess is deprecated!" \
-                                    "Use ActiveSupport::HashWithIndifferentAccess instead."
-    super
-  end
-
-  def encode_with(coder)
-    coder.represent_object(nil, ActiveSupport::HashWithIndifferentAccess.new(self))
-  end
-end
+HashWithIndifferentAccess = ActiveSupport::HashWithIndifferentAccess
diff --git a/activesupport/test/core_ext/hash_ext_test.rb b/activesupport/test/core_ext/hash_ext_test.rb
index 042bb60a22..05813ad388 100644
--- a/activesupport/test/core_ext/hash_ext_test.rb
+++ b/activesupport/test/core_ext/hash_ext_test.rb
@@ -8,8 +8,6 @@ require "active_support/core_ext/object/deep_dup"
 require "active_support/inflections"
 
 class HashExtTest < ActiveSupport::TestCase
-  HashWithIndifferentAccess = ActiveSupport::HashWithIndifferentAccess
-
   class IndifferentHash < ActiveSupport::HashWithIndifferentAccess
   end
 
@@ -1080,25 +1078,6 @@ class HashExtTest < ActiveSupport::TestCase
     assert_equal 1, hash[:a]
     assert_equal 3, hash[:b]
   end
-
-  def test_top_level_hash_with_indifferent_access_is_deprecated
-    assert_deprecated do
-      ::HashWithIndifferentAccess.new
-    end
-  end
-
-  def test_top_level_hash_with_indifferent_access_can_be_extended
-    assert_deprecated do
-      Class.new(::HashWithIndifferentAccess)
-    end
-  end
-
-  def test_yaml_encoding_outputs_an_activesupport_namespaced_constant
-    ActiveSupport::Deprecation.silence do
-      instance = ::HashWithIndifferentAccess.new
-      assert_includes instance.to_yaml, "ActiveSupport::HashWithIndifferentAccess"
-    end
-  end
 end
 
 class IWriteMyOwnXML
@@ -1144,8 +1123,6 @@ class HashExtToParamTests < ActiveSupport::TestCase
 end
 
 class HashToXmlTest < ActiveSupport::TestCase
-  HashWithIndifferentAccess = ActiveSupport::HashWithIndifferentAccess
-
   def setup
     @xml_options = { root: :person, skip_instruct: true, indent: 0 }
   end