Allowing zero-like values as env variables

[bryan-garcia]

Discussed in #390

^{Originally posted by bryan-garcia April 29, 2022}
Hi Everyone,

There is an issue when providing integer 0 or float 0 in the env.variables block that triggers a ValueError being raised. Specifically it's in yamlspecification.py (method _verify_variables on line 190):

if not value:
    msg = (
        "All variables must have a valid value. Empty strings "
        "are not allowed."
    )
    logger.error(msg)
    raise ValueError(msg)

A value of integer/float 0 in the env.variables block clearly triggers this error.

Sometimes I don't want to use the global.parameter block to define my values, and simply want an env variable. What are some thoughts for allowing this from a design perspective?

[FrankD412]

Ah that is clearly an oversight -- yeah, the not value is a little too broad and catches the 0. That's a simple fix. For the other bit I'll pick this up in the discussion thread since I'm curious what the use case is.