Fallback on "invalid" with missing translation

When `config.i18n.raise_on_missing_translations` is enabled, Rails 7.1
raises on missing translation error when validation messages are not
translated, which is a new behavior causing CSV to fail

For unsupported validations, like `comparison`, and custom validations,
like `timeliness`, CSV attempts to create a message for a key that
is not present.

This commit standardizes the behavior and fallbacks on "invalid" when
a translation is not found, which is supposed to be the desired
behavior for this use case

Close #920

lib/client_side_validations/active_model.rb

@@ -18,7 +18,24 @@ def copy_conditional_attributes(attribute_to, attribute_from)
       private
 
       def build_client_side_hash(model, attribute, options)
-        { message: model.errors.generate_message(attribute, message_type, options) }.merge(options.except(*callbacks_options - %i[allow_blank if unless]))
+        # Rails mutates `options` object when calling `model.errors.generate_message`
+        # by removing `message` option, if any.
+        # By raising on missing translations, CSV has the same behavior across
+        # all supported Rails versions and `config.i18n.raise_on_missing_translations`
+        # possible configurations.
+        options[:raise] = true
+
+        message =
+          begin
+            model.errors.generate_message(attribute, message_type, options)
+          rescue I18n::MissingTranslationData
+            options[:message] = :invalid
+            model.errors.generate_message(attribute, message_type, options)
+          end
+
+        options.delete(:raise)
+
+        { message: message }.merge(options.except(*callbacks_options - %i[allow_blank if unless]))
       end
 
       def message_type

test/active_model/cases/test_validations.rb

@@ -484,6 +484,23 @@ def test_multiple_validators_of_same_type_on_same_attribute
       assert_equal expected_hash, person.client_side_validation_hash
     end
 
+    def test_missing_translation
+      person = new_person do |p|
+        p.validates :first_name, comparison: { other_than: :last_name }
+      end
+
+      expected_hash = {
+        first_name: {
+          comparison: [{
+            message:    'is invalid',
+            other_than: :last_name
+          }]
+        }
+      }
+
+      assert_equal expected_hash, person.client_side_validation_hash
+    end
+
     def test_ignored_procs_validators
       person = new_person do |p|
         p.validates :first_name, format: proc { |o| o.matcher }