Return null type format when format is not know

When requesting a controller with the following code with a unknown format:

    def my_action
      respond_to do |format|
        format.json { head :ok }
        format.any { render text: 'Default response' }
      end
    end

we should render the default response instead of raising ActionController::UnknownFormat

Fixes #14462

Conflicts:
	actionpack/CHANGELOG.md
	actionpack/test/controller/mime/respond_with_test.rb

Conflicts:
	actionpack/CHANGELOG.md

3 files changed, 13 insertions, 1 deletions

diff --git a/actionpack/CHANGELOG.md b/actionpack/CHANGELOG.md
index 513f2e66fb..a45a54b1c7 100644
--- a/actionpack/CHANGELOG.md
+++ b/actionpack/CHANGELOG.md
@@ -1,3 +1,10 @@
+*   Returns null type format when format is not know and controller is using `any`
+    format block.
+
+    Fixes #14462.
+
+    *Rafael Mendonça França*
+
 *   Improve routing error page with fuzzy matching search.
 
     *Winston*
diff --git a/actionpack/lib/action_dispatch/http/mime_negotiation.rb b/actionpack/lib/action_dispatch/http/mime_negotiation.rb
index b803ce8b6f..0b2b60d2e4 100644
--- a/actionpack/lib/action_dispatch/http/mime_negotiation.rb
+++ b/actionpack/lib/action_dispatch/http/mime_negotiation.rb
@@ -129,7 +129,7 @@ module ActionDispatch
           end
         end
 
-        order.include?(Mime::ALL) ? formats.first : nil
+        order.include?(Mime::ALL) ? format : nil
       end
 
       protected
diff --git a/actionpack/test/controller/mime/respond_to_test.rb b/actionpack/test/controller/mime/respond_to_test.rb
index 499c62cc35..ce6d135d92 100644
--- a/actionpack/test/controller/mime/respond_to_test.rb
+++ b/actionpack/test/controller/mime/respond_to_test.rb
@@ -492,6 +492,11 @@ class RespondToControllerTest < ActionController::TestCase
     assert_equal 'Whatever you ask for, I got it', @response.body
   end
 
+  def test_handle_any_any_unkown_format
+    get :handle_any_any, { format: 'php' }
+    assert_equal 'Whatever you ask for, I got it', @response.body
+  end
+
   def test_browser_check_with_any_any
     @request.accept = "application/json, application/xml"
     get :json_xml_or_html