branch.composePublicURL 500s if scheme is unknown

[Jelmer Vernooij]

  File "/home/jelmer/src/breezy/lp-anonymous/breezy/plugins/launchpad/lp_directory.py", line 112, in _resolve_via_api
    return {'urls': [lp_branch.composePublicURL(scheme='bzr+ssh'), lp_branch.composePublicURL(scheme='https')]}
                                                                   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/lib/python3/dist-packages/lazr/restfulclient/resource.py", line 642, in __call__
    response, content = self.root._browser._request(
                        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/lib/python3/dist-packages/lazr/restfulclient/_browser.py", line 484, in _request
    raise error
lazr.restfulclient.errors.ServerError: HTTP Error 500: Internal Server Error
Response headers:
---
connection: close
content-length: 14
content-type: text/plain;charset=utf-8
date: Wed, 11 Jan 2023 18:25:46 GMT
server: gunicorn/19.8.1
status: 500
x-lazr-oopsid: OOPS-1e2edc7b84b1d29d16080ef63591190a
x-powered-by: Zope (www.zope.org), Python (www.python.org)
x-request-id: a8f424d0-176e-4bc6-bcb2-69d07f687711
x-vcs-revision: 0dc4a5528db5ce4d3653ad53877575d20a6f2d2f
---
Response body:
---
b'AssertionError'

[Jürgen Gmach (jugmac00)]

Do you have a fix in mind? Obviously, you want to have support for https.

Should there be a client side error (4xx) when an unknown scheme is requested?