Raise ArgumentError if attempting to transliterate anything that is not a string

2 files changed, 20 insertions, 0 deletions

diff --git a/activesupport/lib/active_support/inflector/transliterate.rb b/activesupport/lib/active_support/inflector/transliterate.rb
index 3e78986e8e..de6dd2720b 100644
--- a/activesupport/lib/active_support/inflector/transliterate.rb
+++ b/activesupport/lib/active_support/inflector/transliterate.rb
@@ -57,6 +57,8 @@ module ActiveSupport
     #   transliterate('Jürgen')
     #   # => "Juergen"
     def transliterate(string, replacement = "?".freeze)
+      raise ArgumentError, "Can only transliterate strings. Received #{string.class.name}" unless string.is_a?(String)
+
       I18n.transliterate(ActiveSupport::Multibyte::Unicode.normalize(
         ActiveSupport::Multibyte::Unicode.tidy_bytes(string), :c),
           replacement: replacement)
diff --git a/activesupport/test/transliterate_test.rb b/activesupport/test/transliterate_test.rb
index 040ddd25fc..466b69bcef 100644
--- a/activesupport/test/transliterate_test.rb
+++ b/activesupport/test/transliterate_test.rb
@@ -31,4 +31,22 @@ class TransliterateTest < ActiveSupport::TestCase
   def test_transliterate_should_allow_a_custom_replacement_char
     assert_equal "a*b", ActiveSupport::Inflector.transliterate("a索b", "*")
   end
+
+  def test_transliterate_handles_empty_string
+    assert_equal "", ActiveSupport::Inflector.transliterate("")
+  end
+
+  def test_transliterate_handles_nil
+    exception = assert_raises ArgumentError do
+      ActiveSupport::Inflector.transliterate(nil)
+    end
+    assert_equal "Can only transliterate strings. Received NilClass", exception.message
+  end
+
+  def test_transliterate_handles_unknown_object
+    exception = assert_raises ArgumentError do
+      ActiveSupport::Inflector.transliterate(Object.new)
+    end
+    assert_equal "Can only transliterate strings. Received Object", exception.message
+  end
 end