[ruby-core:117087] [Ruby master Bug#20328] optparse omits the option's description in the --help output if the description is an Array

7 Mar 2024

      Issue #20328 has been updated by postmodern (Hal Brodigan).

Ah ha! I suppose also adding an explicit option type class would help differentiate between option's desired value and the description lines?

```ruby
  opts.on('-m', '--multiline-opt', String, 'Line one', 'Line two') do |test|
  end
```

However, if I pass in both a `String` class, indicating the option's value type, and follow it with an Array of description lines, the description still gets silently omitted.

```ruby
  opts.on('-m', '--multiline-opt VALUE', String, ['Line one', 'Line two']) do |test|
  end
```

```
usage: test.rb [options]
    -o, --opt [OPT]                  Line one
    -m, --multiline-opt VALUE
    -h, --help                       Prints this help
```

----------------------------------------
Bug #20328: optparse omits the option's description in the --help output if the description is an Array
https://bugs.ruby-lang.org/issues/20328#change-107161

* Author: postmodern (Hal Brodigan)
* Status: Open
* ruby -v: ruby 3.2.2 (2023-03-30 revision e51014f9c0) [x86_64-linux]
* Backport: 3.0: UNKNOWN, 3.1: UNKNOWN, 3.2: UNKNOWN, 3.3: UNKNOWN
----------------------------------------
If you define an option using `OptionParser#on`, but give the option's description as a multi-line Array, then the option's description is omitted from the `--help` output.

## Steps To Reproduce

```ruby
#!/usr/bin/env ruby

require 'optparse'

optparser = OptionParser.new do |opts|
  opts.banner = 'usage: test.rb [options]'

  opts.on('-o', '--opt [OPT]', 'Line one') do |opt|
  end

  opts.on('-m', '--multiline-opt', ['Line one', 'Line two']) do |test|
  end

  opts.on('-h', '--help', 'Prints this help') do
    puts opts
    exit
  end
end

optparser.parse(['--help'])
```

### Expected result

```
usage: test.rb [options]
    -o, --opt [OPT]                  Line one
    -m, --multiline-opt              Line one
                                     Line two
    -h, --help                       Prints this help
```

### Actual Result

```
usage: test.rb [options]
    -o, --opt [OPT]                  Line one
    -m, --multiline-opt
    -h, --help                       Prints this help
```

or an `ArgumentError` should be raised if Array descriptions are not allowed/supported.

## Version Info

Tested against optparse 0.1.0, 0.2.0, 0.3.1, and the master branch.

-- 
https://bugs.ruby-lang.org/