1 files changed, 15 insertions, 4 deletions
diff --git a/actionpack/lib/action_dispatch/request/utils.rb b/actionpack/lib/action_dispatch/request/utils.rb
index 8b43cdada8..9d4f1aa3c5 100644
--- a/actionpack/lib/action_dispatch/request/utils.rb
+++ b/actionpack/lib/action_dispatch/request/utils.rb
@@ -1,18 +1,29 @@
 module ActionDispatch
   class Request < Rack::Request
     class Utils # :nodoc:
+
+      mattr_accessor :perform_deep_munge
+      self.perform_deep_munge = true
+
       class << self
         # Remove nils from the params hash
-        def deep_munge(hash)
+        def deep_munge(hash, keys = [])
+          return hash unless perform_deep_munge
+
           hash.each do |k, v|
+            keys << k
             case v
             when Array
-              v.grep(Hash) { |x| deep_munge(x) }
+              v.grep(Hash) { |x| deep_munge(x, keys) }
               v.compact!
-              hash[k] = nil if v.empty?
+              if v.empty?
+                hash[k] = nil
+                ActiveSupport::Notifications.instrument("deep_munge.action_controller", keys: keys)
+              end
             when Hash
-              deep_munge(v)
+              deep_munge(v, keys)
             end
+            keys.pop
           end
 
           hash