Use of ParameterFilter no longer forces `request.filtered_parameters' class to be Hash

- Fixes issue described on #27944
- `filtered_query_string` used an Array representation of what
semantically is a key value pair: better suited for a Hash.  Without
this change `filtered_params = original_params.class.new` returns an
Array with unintended consequences.

1 files changed, 13 insertions, 0 deletions

diff --git a/actionpack/test/dispatch/request_test.rb b/actionpack/test/dispatch/request_test.rb
index 2f9228a62d..baa4a0b3b4 100644
--- a/actionpack/test/dispatch/request_test.rb
+++ b/actionpack/test/dispatch/request_test.rb
@@ -1098,6 +1098,19 @@ class RequestParameterFilter < BaseRequestTest
     end
   end
 
+  test "parameter filter should maintain hash with indifferent access" do
+    test_hashes = [
+      [{'foo'=>'bar'}.with_indifferent_access, %w'food'],
+      [{'foo'=>'bar'}.with_indifferent_access, []]
+    ]
+
+    test_hashes.each do |before_filter, filter_words|
+      parameter_filter = ActionDispatch::Http::ParameterFilter.new(filter_words)
+      assert_instance_of ActiveSupport::HashWithIndifferentAccess,
+                         parameter_filter.filter(before_filter)
+    end
+  end
+
   test "filtered_parameters returns params filtered" do
     request = stub_request(
       "action_dispatch.request.parameters" => {