env FOO=BAR
! exec pint --no-color config
! stdout .
cmp stderr stderr.txt

-- stderr.txt --
level=INFO msg="Loading configuration file" path=.pint.hcl
level=ERROR msg="Execution completed with error(s)" err="failed to load config file \".pint.hcl\": .pint.hcl:7,17-29: Unknown variable; There is no variable named \"ENV_AUTH_KEY\"., and 1 other diagnostic(s)"
-- .pint.hcl --
parser {
  relaxed = [".*"]
}
prometheus "prod" {
  uri = "http://localhost"
  headers = {
    X-Auth = "${ENV_AUTH_KEY}"
  }
}
rule {
    match {
      kind = "recording"
    }
    aggregate ".+" {
        keep = [ "${ENV_FOO}" ]
    }
}
