dup the request and mutate its headers object.

duping the request will dup it's underlying env hash.

1 files changed, 2 insertions, 2 deletions

diff --git a/actionpack/lib/action_dispatch/http/headers.rb b/actionpack/lib/action_dispatch/http/headers.rb
index 40053e521a..05191ff2fd 100644
--- a/actionpack/lib/action_dispatch/http/headers.rb
+++ b/actionpack/lib/action_dispatch/http/headers.rb
@@ -66,13 +66,13 @@ module ActionDispatch
       end
 
       def each(&block)
-        env.each(&block)
+        @req.each_header(&block)
       end
 
       # Returns a new Http::Headers instance containing the contents of
       # <tt>headers_or_env</tt> and the original instance.
       def merge(headers_or_env)
-        headers = Http::Headers.new(ActionDispatch::Request.new(env.dup))
+        headers = @req.dup.headers
         headers.merge!(headers_or_env)
         headers
       end