Merge pull request rails#46615 from nickh/nh-fix-transliterate

Return a copy of the source string when transliterating

Author: rafaelfranca

activesupport/lib/active_support/inflector/transliterate.rb

@@ -65,8 +65,8 @@ def transliterate(string, replacement = "?", locale: nil)
       raise ArgumentError, "Can only transliterate strings. Received #{string.class.name}" unless string.is_a?(String)
       raise ArgumentError, "Cannot transliterate strings with #{string.encoding} encoding" unless ALLOWED_ENCODINGS_FOR_TRANSLITERATE.include?(string.encoding)
 
+      return string.dup if string.ascii_only?
       string = string.dup if string.frozen?
-      return string if string.ascii_only?
 
       input_encoding = string.encoding
 

activesupport/test/transliterate_test.rb

@@ -106,4 +106,11 @@ def test_transliterate_handles_strings_with_invalid_gb18030_bytes
     string = String.new("\255", encoding: Encoding::GB18030).freeze
     assert_equal "?", ActiveSupport::Inflector.transliterate(string)
   end
+
+  def test_transliterate_returns_a_copy_of_ascii_strings
+    string = "Test String".dup
+    assert_not string.frozen?
+    assert string.ascii_only?
+    assert_not_equal string.object_id, ActiveSupport::Inflector.transliterate(string).object_id
+  end
 end