Fix OptionParser to handle sub-commands with hyphen

[erdnaxeli]

It was matching regexs anywhere on the string, but we want the regexs to
match the full string. In particular this behavior made that a flag
sub-command was interpeted as su, because it matches the -(.)\S+
regex.

[aravindavk]

This PR looks good to me. Any help required to get this Patch merged?

I also faced the same issue and sent patch #9481 Abandoned it after noticing this patch.

[erdnaxeli]

This PR looks good to me. Any help required to get this Patch merged?

I'm not sure what is the process to get reviewed and / or merged.

[aravindavk]

Based on the file history including @RX14 for review. Thanks.

[straight-shoota]

This should better use \A and \z instead of ^ and $.
The difference may not be relevant for this use case because flags usually don't contain newline characters, but it's the right tool for this.

[erdnaxeli]

@straight-shoota I didn't know about this, it seems you're right: https://guides.rubyonrails.org/security.html#regular-expressions.

I fixed it, thanks. I didn't write test for it because I am wondering what we should expect when someone puts a newline in a flag.

[straight-shoota]

It should be lower-case \z, though.

[erdnaxeli]

Indeed, from ruby doc:

• \Z - Matches end of string. If string ends with a newline, it matches just before newline
• \z - Matches end of string