Treat html suffix in controller translation

There are some difference between translation in a view and translation
in a controller.
This will treat html suffix in controller translation.

Closes #27862.

Co-authored-by: Rui Onodera <deraru@gmail.com>
Co-authored-by: Gavin Miller <gavingmiller@gmail.com>

actionpack/CHANGELOG.md

@@ -1,3 +1,7 @@
+*   Treat html suffix in controller translation.
+
+    *Rui Onodera*, *Gavin Miller*
+
 *   Allow permitting numeric params.
 
     Previously it was impossible to permit different fields on numeric parameters.

actionpack/lib/abstract_controller/translation.rb

@@ -22,7 +22,20 @@ module AbstractController
       end
 
       i18n_raise = options.fetch(:raise, self.raise_on_missing_translations)
-      I18n.translate(key, **options, raise: i18n_raise)
+
+      if html_safe_translation_key?(key)
+        html_safe_options = options.dup
+        options.except(*I18n::RESERVED_KEYS).each do |name, value|
+          unless name == :count && value.is_a?(Numeric)
+            html_safe_options[name] = ERB::Util.html_escape(value.to_s)
+          end
+        end
+        translation = I18n.translate(key, **html_safe_options, raise: i18n_raise)
+
+        translation.respond_to?(:html_safe) ? translation.html_safe : translation
+      else
+        I18n.translate(key, **options, raise: i18n_raise)
+      end
     end
     alias :t :translate
 
@@ -31,5 +44,10 @@ module AbstractController
       I18n.localize(object, **options)
     end
     alias :l :localize
+
+    private
+      def html_safe_translation_key?(key)
+        /(\b|_|\.)html$/.match?(key.to_s)
+      end
   end
 end

actionpack/test/abstract/translation_test.rb

@@ -20,6 +20,10 @@ module AbstractController
               translation: {
                 index: {
                   foo: "bar",
+                  hello: "<a>Hello World</a>",
+                  hello_html: "<a>Hello World</a>",
+                  interpolated_html: "<a>Hello %{word}</a>",
+                  nested: { html: "<a>nested</a>" }
                 },
                 no_action: "no_action_tr",
               },
@@ -95,6 +99,43 @@ module AbstractController
           assert_equal expected, @controller.l(time)
         end
       end
+
+      def test_translate_does_not_mark_plain_text_as_safe_html
+        @controller.stub :action_name, :index do
+          translation = @controller.t(".hello")
+          assert_equal "<a>Hello World</a>", translation
+          assert_equal false, translation.html_safe?
+        end
+      end
+
+      def test_translate_marks_translations_with_a_html_suffix_as_safe_html
+        @controller.stub :action_name, :index do
+          translation = @controller.t(".hello_html")
+          assert_equal "<a>Hello World</a>", translation
+          assert_equal true, translation.html_safe?
+        end
+      end
+
+      def test_translate_marks_translation_with_nested_html_key
+        @controller.stub :action_name, :index do
+          translation = @controller.t(".nested.html")
+          assert_equal "<a>nested</a>", translation
+          assert_equal true, translation.html_safe?
+        end
+      end
+
+      def test_translate_escapes_interpolations_in_translations_with_a_html_suffix
+        word_struct = Struct.new(:to_s)
+        @controller.stub :action_name, :index do
+          translation = @controller.t(".interpolated_html", word: "<World>")
+          assert_equal "<a>Hello &lt;World&gt;</a>", translation
+          assert_equal true, translation.html_safe?
+
+          translation = @controller.t(".interpolated_html", word: word_struct.new("<World>"))
+          assert_equal "<a>Hello &lt;World&gt;</a>", translation
+          assert_equal true, translation.html_safe?
+        end
+      end
     end
   end
 end