Merge pull request #13982 from dskang/fix-response-flatten-infinite-recursion

Fix response flatten infinite recursion

actionpack/lib/action_dispatch/http/response.rb

@@ -313,7 +313,7 @@ def rack_response(status, header)
         header.delete CONTENT_TYPE
         [status, header, []]
       else
-        [status, header, self]
+        [status, header, Rack::BodyProxy.new(self){}]
       end
     end
   end

actionpack/test/dispatch/response_test.rb

@@ -217,6 +217,24 @@ def test_response_body_encoding
     assert_not @response.respond_to?(:method_missing)
     assert @response.respond_to?(:method_missing, true)
   end
+
+  test "can be destructured into status, headers and an enumerable body" do
+    response = ActionDispatch::Response.new(404, { 'Content-Type' => 'text/plain' }, ['Not Found'])
+    status, headers, body = response
+
+    assert_equal 404, status
+    assert_equal({ 'Content-Type' => 'text/plain' }, headers)
+    assert_equal ['Not Found'], body.each.to_a
+  end
+
+  test "[response].flatten does not recurse infinitely" do
+    Timeout.timeout(1) do # use a timeout to prevent it stalling indefinitely
+      status, headers, body = [@response].flatten
+      assert_equal @response.status, status
+      assert_equal @response.headers, headers
+      assert_equal @response.body, body.each.to_a.join
+    end
+  end
 end
 
 class ResponseIntegrationTest < ActionDispatch::IntegrationTest