pr-pull: handle empty string cases
pr-pull: handle empty string cases

Co-authored-by: Mike McQuaid <a17fed27eaa842282862ff7c1b9c8395a26ac320@mikemcquaid.com>
JCount/brew,MikeMcQuaid/brew,nandub/brew,Homebrew/brew,MikeMcQuaid/brew,nandub/brew,JCount/brew,sjackman/homebrew,EricFromCanada/brew,EricFromCanada/brew,claui/brew,nandub/brew,sjackman/homebrew,claui/brew,konqui/brew,sjackman/homebrew,claui/brew,EricFromCanada/brew,JCount/brew,reitermarkus/brew,vitorgalvao/brew,reitermarkus/brew,Homebrew/brew,reitermarkus/brew,mahori/brew,vitorgalvao/brew,EricFromCanada/brew,vitorgalvao/brew,MikeMcQuaid/brew,MikeMcQuaid/brew,vitorgalvao/brew,reitermarkus/brew,konqui/brew,JCount/brew,mahori/brew,sjackman/homebrew,Homebrew/brew,konqui/brew,nandub/brew,Homebrew/brew,claui/brew,konqui/brew,mahori/brew,mahori/brew