Raise errors for ASCII-8BIT encoding in ActiveSupport::Inflector::transliterate

Adds ArgumentErrors to `ActiveSupport::Inflector::transliterate` if a string is  with ASCII-8BIT which will raise an error in `unicode_normalize`.

2 files changed, 12 insertions, 0 deletions

diff --git a/activesupport/lib/active_support/inflector/transliterate.rb b/activesupport/lib/active_support/inflector/transliterate.rb
index ec6e9ccb59..61651ba101 100644
--- a/activesupport/lib/active_support/inflector/transliterate.rb
+++ b/activesupport/lib/active_support/inflector/transliterate.rb
@@ -56,8 +56,12 @@ module ActiveSupport
     #
     #   transliterate('Jürgen', locale: :de)
     #   # => "Juergen"
+    #
+    # Transliteration of ASCII-8BIT / BINARY strings is not
+    # supported and will raise an ArgumentError.
     def transliterate(string, replacement = "?", locale: nil)
       raise ArgumentError, "Can only transliterate strings. Received #{string.class.name}" unless string.is_a?(String)
+      raise ArgumentError, "Can not transliterate strings with ASCII-8BIT encoding" if string.encoding == ::Encoding::ASCII_8BIT
 
       I18n.transliterate(
         ActiveSupport::Multibyte::Unicode.tidy_bytes(string).unicode_normalize(:nfc),
diff --git a/activesupport/test/transliterate_test.rb b/activesupport/test/transliterate_test.rb
index 9e29a93ea0..620bb20305 100644
--- a/activesupport/test/transliterate_test.rb
+++ b/activesupport/test/transliterate_test.rb
@@ -57,4 +57,12 @@ class TransliterateTest < ActiveSupport::TestCase
     end
     assert_equal "Can only transliterate strings. Received Object", exception.message
   end
+
+  def test_transliterate_handles_ascci_8bit_strings
+    ascii_8bit_string = "A".b
+    exception = assert_raises ArgumentError do
+      ActiveSupport::Inflector.transliterate(ascii_8bit_string)
+    end
+    assert_equal "Can not transliterate strings with ASCII-8BIT encoding", exception.message
+  end
 end