Consider regex validation of plugin names

[jthegedus]

Is your feature request related to a problem? Please describe.
Currently we allow users to specify anything as a plugin name. We should probably validate plugin names against an allowed list of characters, as in the future with tabular output the parsing may be effected by POSIX character classes appearing within plugin names.

• asdf plugin add nodejs : is valid
• asdf plugin add 🚀🍾🎉 : is invalid

Describe the solution you'd like
Simple regex validation of plugin name in lib/commands/command-plugin-add.bash

Additional context
[:space:] is probably already one character we should not allow

[danhper]

I agree this would be a good idea. I think pretty much any printable character except from spaces should be ok. Or should we stick with ascii?

[jthegedus]

I think pretty much any printable character except from spaces should be ok. Or should we stick with ascii?

I had the same thoughts. People will try using unicode and emojis 😆

ASCII is the safe bet IMO, especially when considering the environments asdf would be run in

[danhper]

Agreed, as much as I like emojis, asdf-:rocket::champagne::tada: is probably not a great plugin name :joy:
So I guess the regexp would be something along the lines of asdf-[a-zA-Z0-9-] ?
Do we want to allow ., _, $ or other symbols. I kind of feel dashes are enough and we currently don't have any plugin using such symbols.

[jthegedus]

I've no idea of what downstream effects specific chars like $ or . could have in the codebase, but [a-zA-Z0-9-] is plenty IMO.