Merge pull request #29553 from eugeneius/wrap_parameters_nil

Don't wrap parameters if key already exists

2 files changed, 9 insertions, 1 deletions

diff --git a/actionpack/lib/action_controller/metal/params_wrapper.rb b/actionpack/lib/action_controller/metal/params_wrapper.rb
index 68881b8402..44151c9f71 100644
--- a/actionpack/lib/action_controller/metal/params_wrapper.rb
+++ b/actionpack/lib/action_controller/metal/params_wrapper.rb
@@ -282,7 +282,7 @@ module ActionController
         return false unless request.has_content_type?
 
         ref = request.content_mime_type.ref
-        _wrapper_formats.include?(ref) && _wrapper_key && !request.request_parameters[_wrapper_key]
+        _wrapper_formats.include?(ref) && _wrapper_key && !request.request_parameters.key?(_wrapper_key)
       end
   end
 end
diff --git a/actionpack/test/controller/params_wrapper_test.rb b/actionpack/test/controller/params_wrapper_test.rb
index 2a41d57b26..4cbb28ef60 100644
--- a/actionpack/test/controller/params_wrapper_test.rb
+++ b/actionpack/test/controller/params_wrapper_test.rb
@@ -170,6 +170,14 @@ class ParamsWrapperTest < ActionController::TestCase
     end
   end
 
+  def test_no_double_wrap_if_key_exists_and_value_is_nil
+    with_default_wrapper_options do
+      @request.env["CONTENT_TYPE"] = "application/json"
+      post :parse, params: { "user" => nil }
+      assert_parameters("user" => nil)
+    end
+  end
+
   def test_nested_params
     with_default_wrapper_options do
       @request.env["CONTENT_TYPE"] = "application/json"