A Ruby example app (updated recently in fermyon/developer#1406) utilizing the wagi executor runs as expected, however an error does show up in the logs:
$ spin up
Logging component stdio to ".spin/logs/"
Serving http://127.0.0.1:3000
Available Routes:
ruby: http://127.0.0.1:3000
2024-10-30T22:37:06.498213Z ERROR spin_http::wagi: Invalid header name error=invalid HTTP header name header_name=ruby 3.4.0dev (2024-06-28T17
(Using spin 2.8.0-pre0 (8c036a12 2024-10-30))