Raise an error if email set to ""

[MarkEdmondson1234]

In a non-interactive environment, it is recommended to supply option("gargle_oauth_email") to TRUE or an email so avoid the interactive menu. Setting this option via a Sys.getenv() call can be convenient for multiple users.

However, if the environment argument is not set Sys.getenv() returns "" which is not raised as an error in token_fetch() or otherwise:

token_fetch(email = Sys.getenv("NOT_SET"))
#The gargle package is requesting access to your Google account. Select a pre-authorised account or enter '0' to obtain a new token. Press Esc/Ctrl + C to abort.

If the function checked for a valid email (something simple like checking it has a @ present would help) then downstream errors will be easier and more informative.