Proposal: require_keys should flag blank/whitespace ENV values

[Grigore-George-Mihai]

Dotenv.require_keys only checks key presence, so FOO= or FOO=" " pass, which can mask misconfiguration.

Old

def require_keys(*keys)
  missing_keys = keys.flatten - ::ENV.keys
  return if missing_keys.empty?
  raise MissingKeys, missing_keys
end

New:

def require_keys(*keys) 
  missing_keys = keys.flatten.select { |k| ENV[k].to_s.strip.empty? } 
  raise MissingKeys, missing_keys unless missing_keys.empty? 
end

[bkeepers]

This would be a breaking change and would need to wait until the next major release, but I'm not opposed if someone wants to create a pull request.