anchor.diff:      {true, file_ctx:ctx()} |
       {false, token_utils:guid_constraints(), file_ctx:ctx()}.
   check_and_cache_guid_constraints_fulfillment(FileCtx, CacheKey, GuidConstraints) ->
  -    FileGuid = file_ctx:get_guid_const(FileCtx),
  +    FileGuid = get_file_guid(FileCtx),
       RemainingGuidConstraints = lists:filter(fun(GuidsSet) ->
           not lists:member(FileGuid, GuidsSet)
       end, GuidConstraints),
  
positive.code:         SessionAuth ->
              SessionAuth
      end.
  
negative.code: does_fulfills_guid_constraints(
      UserCtx, SessionDiscriminator, FileCtx, AllGuidConstraints
  ) ->
      FileGuid = get_file_guid(FileCtx),
      CacheKey = {guid_constraint, SessionDiscriminator, FileGuid},
  
      case permissions_cache:check_permission(CacheKey) of
  