dig: Incorrect encoding to punycode

Summary

Incorrect/invalid output when trying to encode the domain: ☺.unicode.

It appears the punycode encoder generates a domain label that includes a space. Several punycode generators do this, including dnspython and Python's IDNA encoding built-in.

This came up while performing testing ahead of migrating towards a new system of handling DNS records which uses Python, however, we've subsequently identified that it affects dig as well.

BIND version used

9.11.5-P4-5.1-Debian (From Debian Buster)

Steps to reproduce

$ dig ☺.unicode

What is the current bug behavior?

dig: 'xn--\032o-oia59s.unicode.' is not a legal IDNA2008 name (string contains a disallowed character), use +noidnout

What is the expected correct behavior?

I'd expect dig to look up the A record for the correctly encoded domain. I'm not sure what the correctly encoded domain is, although my suspicion is that it should be xn--xba3f15e.unicode.

Relevant configuration files

Not sure that any config files are actually relevant - if there are, please let me know.