check for the empty string
check for the empty string

Summary:
Bug:

{F157985015}

Reviewed By: danielbuechele

Differential Revision: D15260689

fbshipit-source-id: c43cdc0fc0d3e624ad930af60a9c95996579acb6

facebook/flipper,facebook/flipper,facebook/flipper,facebook/flipper,facebook/flipper,facebook/flipper,facebook/flipper,facebook/flipper,facebook/flipper,facebook/flipper,facebook/flipper