ruby on rails - Using a frozen constant as a hash key? -

i built small api makes few calls have similar payloads, have base payload merge in call-specific elements, so:

def foo_call   base_payload.merge({"request.id" => request_id}) end  def biz_call   base_payload.merge({"request.id" => some_other_thing}) end  def base_payload   {     bar: bar,     baz: baz,     "request.id" => default_id   } end 

my coworker suggested make "request.id" frozen constant, arguing making constant means can freeze means wont allocating new string object on each call, saving bit of memory. this:

requestid = "request.id".freeze  def foo_call   base_payload.merge({requestid => request_id}) end  def biz_call   base_payload.merge({requestid => some_other_thing}) end  def base_payload   {     bar: bar,     baz: baz,     requestid => default_id   } end 

i'm little apprehensive, can't quite pin down reason why not (other latent resistance @ having new commit :>). feel might cause weirdness have same object key in multiple hashes -- merging in object "request.id" might not overwrite original string base_payload -- or won't see memory saved since hash have clone string hash key anyway, i'm not sure.

am being overly paranoid/resistant?