Remove deprecated support to setting attr_internal_naming_format with a @ prefix

Author: rafaelfranca

activesupport/CHANGELOG.md

@@ -1,3 +1,7 @@
+*   Remove deprecated support to setting `attr_internal_naming_format` with a `@` prefix.
+
+    *Rafael Mendonça França*
+
 *   Remove deprecated `ActiveSupport::ProxyObject`.
 
     *Rafael Mendonça França*

activesupport/lib/active_support/core_ext/module/attr_internal.rb

@@ -24,14 +24,13 @@ class << self
 
     def attr_internal_naming_format=(format)
       if format.start_with?("@")
-        ActiveSupport.deprecator.warn <<~MESSAGE
-          Setting `attr_internal_naming_format` with a `@` prefix is deprecated and will be removed in Rails 8.0.
+        raise ArgumentError, <<~MESSAGE.squish
+          Setting `attr_internal_naming_format` with a `@` prefix is not supported.
 
           You can simply replace #{format.inspect} by #{format.delete_prefix("@").inspect}.
         MESSAGE
-
-        format = format.delete_prefix("@")
       end
+
       @attr_internal_naming_format = format
     end
   end

activesupport/test/core_ext/module/attr_internal_test.rb

@@ -44,12 +44,11 @@ def test_accessor
     assert_nothing_raised { assert_equal 1, @instance.foo }
   end
 
-  def test_naming_format_deprecation
+  def test_invalid_naming_format
     assert_equal "_%s", Module.attr_internal_naming_format
-    assert_deprecated(ActiveSupport.deprecator) do
+    assert_raises(ArgumentError) do
       Module.attr_internal_naming_format = "@___%s"
     end
-    assert_equal "___%s", Module.attr_internal_naming_format
   end
 
   def test_naming_format

guides/source/8_0_release_notes.md

@@ -142,6 +142,8 @@ Please refer to the [Changelog][active-support] for detailed changes.
 
 *   Remove deprecated `ActiveSupport::ProxyObject`.
 
+*   Remove deprecated support to setting `attr_internal_naming_format` with a `@` prefix.
+
 ### Deprecations
 
 ### Notable changes