Opts.env withDefault produces empty braces in usage

[ivan-klass]

Adding withDefault to Opts.env results in confusing empty braces being rendered in usage.

Example:

import cats.syntax.all.given
import com.monovore.decline.{CommandApp, Opts}

object EmptyBraces
    extends CommandApp(
      "test",
      "test",
      (
        Opts.option[Int]("number", "Print N times", metavar = "N"),
        Opts.env[String]("GREETING", "A greeting").withDefault("Hi"), // FIRST []
        Opts.env[String]("BODY", "The content"), // NO DEFAULT - OK
        Opts.env[String]("FOOTER", "Ending").withDefault("Best regards"), // SECOND []
        Opts.option[String]("name", "Who to greet")
      ).mapN { case (n, greeting, body, footer, name) =>
        println(s"$greeting $name\n$body\n$footer" * n)
      }
    )

Usage output:

Missing expected flag --number!
Missing expected environment variable (BODY)!
Missing expected flag --name!

Usage: test --number <N> [] [] --name <string>

test

Options and flags:
    --help
        Display this help text.
    --number <N>
        Print N times
    --name <string>
        Who to greet

Environment Variables:
    GREETING=<string>
        A greeting
    BODY=<string>
        The content
    FOOTER=<string>
        Ending

Note [] [] in Usage: - according to my tests, It seems like every Opts.env(...).withDefault produces an empty braces pair

[Ben Kirwin]

Fascinating - thanks for the report! I'll take a look.

[Ben Kirwin]

2.4.1 is out with the fix. Thanks again for the report!