Add a flag to disable deprecated AC::Parameters comparison

actionpack/lib/action_controller/metal/strong_parameters.rb

@@ -234,6 +234,8 @@ module ActionController
     #    config.action_controller.always_permitted_parameters = %w( controller action format )
     cattr_accessor :always_permitted_parameters, default: %w( controller action )
 
+    cattr_accessor :allow_deprecated_parameters_hash_equality, default: true, instance_accessor: false
+
     class << self
       def nested_attribute?(key, value) # :nodoc:
         /\A-?\d+\z/.match?(key) && (value.is_a?(Hash) || value.is_a?(Parameters))
@@ -268,13 +270,15 @@ module ActionController
       if other.respond_to?(:permitted?)
         permitted? == other.permitted? && parameters == other.parameters
       else
-        if Hash === other
+        if self.class.allow_deprecated_parameters_hash_equality && Hash === other
           ActiveSupport::Deprecation.warn <<-WARNING.squish
             Comparing equality between `ActionController::Parameters` and a
             `Hash` is deprecated and will be removed in Rails 7.1. Please only do
             comparisons between instances of `ActionController::Parameters`. If
             you need to compare to a hash, first convert it using
             `ActionController::Parameters#new`.
+            To disable the deprecated behaviour set
+            `Rails.application.config.action_controller.allow_deprecated_parameters_hash_equality = false`.
           WARNING
           @parameters == other
         else

actionpack/lib/action_controller/railtie.rb

@@ -42,6 +42,11 @@ module ActionController
         end
 
         ActionController::Parameters.action_on_unpermitted_parameters = action_on_unpermitted_parameters
+
+        unless options.allow_deprecated_parameters_hash_equality.nil?
+          ActionController::Parameters.allow_deprecated_parameters_hash_equality =
+            options.allow_deprecated_parameters_hash_equality
+        end
       end
     end
 
@@ -72,7 +77,8 @@ module ActionController
           :permit_all_parameters,
           :action_on_unpermitted_parameters,
           :always_permitted_parameters,
-          :wrap_parameters_by_default
+          :wrap_parameters_by_default,
+          :allow_deprecated_parameters_hash_equality
         )
 
         filtered_options.each do |k, v|

actionpack/test/controller/parameters/accessors_test.rb

@@ -6,6 +6,7 @@ require "action_controller/metal/strong_parameters"
 class ParametersAccessorsTest < ActiveSupport::TestCase
   setup do
     ActionController::Parameters.permit_all_parameters = false
+    ActionController::Parameters.allow_deprecated_parameters_hash_equality = true
 
     @params = ActionController::Parameters.new(
       person: {
@@ -104,6 +105,15 @@ class ParametersAccessorsTest < ActiveSupport::TestCase
     end
   end
 
+  test "deprecated comparison disabled" do
+    ActionController::Parameters.allow_deprecated_parameters_hash_equality = false
+
+    assert_kind_of Enumerator, @params.each_pair
+    assert_not_deprecated do
+      assert_not_equal @params, @params.each_pair.to_h
+    end
+  end
+
   test "each_value carries permitted status" do
     @params.permit!
     @params.each_value do |value|

guides/source/configuring.md

@@ -64,6 +64,7 @@ Below are the default values associated with each target version. In cases of co
 - [`config.add_autoload_paths_to_load_path`](#config-add-autoload-paths-to-load-path): `false`
 - [`config.active_support.default_message_encryptor_serializer`](#config-active-support-default-message-encryptor-serializer): `:json`
 - [`config.active_support.default_message_verifier_serializer`](#config-active-support-default-message-verifier-serializer): `:json`
+- [`config.action_controller.allow_deprecated_parameters_hash_equality`](#config-action-controller-allow-deprecated-parameters-hash-equality): `false`
 
 #### Default Values for Target Version 7.0
 
@@ -1155,6 +1156,18 @@ The default value depends on the `config.load_defaults` target version:
 Configures the [`ParamsWrapper`](https://api.rubyonrails.org/classes/ActionController/ParamsWrapper.html). This can be called at
 the top level, or on individual controllers.
 
+#### `config.action_controller.allow_deprecated_parameters_hash_equality`
+
+Controls behaviour of `ActionController::Parameters#==` with `Hash` arguments.
+Value of the setting determines whether an `ActionController::Parameters` instance is equal to an equivalent `Hash`.
+
+The default value depends on the `config.load_defaults` target version:
+
+| Starting with version | The default value is |
+| --------------------- | -------------------- |
+| (original)            | `true`               |
+| 7.1                   | `false`              |
+
 ### Configuring Action Dispatch
 
 #### `config.action_dispatch.cookies_serializer`

railties/lib/rails/application/configuration.rb

@@ -272,6 +272,10 @@ module Rails
             active_support.default_message_encryptor_serializer = :json
             active_support.default_message_verifier_serializer = :json
           end
+
+          if respond_to?(:action_controller)
+            action_controller.allow_deprecated_parameters_hash_equality = false
+          end
         else
           raise "Unknown version #{target_version.to_s.inspect}"
         end

railties/lib/rails/generators/rails/app/templates/config/initializers/new_framework_defaults_7_1.rb.tt

@@ -24,3 +24,7 @@
 #   "X-Permitted-Cross-Domain-Policies" => "none",
 #   "Referrer-Policy" => "strict-origin-when-cross-origin"
 # }
+
+# Do not treat an `ActionController::Parameters` instance
+# as equal to an equivalent `Hash` by default.
+# Rails.application.config.action_controller.allow_deprecated_parameters_hash_equality = false