/usr/sbin/apt-add-repository will not function with IPv6 proxies called by address

[Matt Clauson]

It appears that if one has an HTTP or HTTPS proxy called out specifically by IPv6 address rather than hostname, it will fail. Placing an entry in /etc/hosts, or the proxy into DNS (and calling by hostname) will function.

failure steps:

1) set proxy environment variables
  export http_proxy="http://[2001:db8:f00::2]:3128/"
  export https_proxy="http://[2001:db8:f00::2]:3128/"

2) Attempt to add repository (in this case, a PPA):
  apt-add-repository ppa:ansible/ansible

3) Enjoy the resulting stack trace:
Traceback (most recent call last):
  File "/usr/bin/apt-add-repository", line 364, in <module>
    sys.exit(0 if addaptrepo.main() else 1)
  File "/usr/bin/apt-add-repository", line 347, in main
    shortcut = handler(source, **shortcut_params)
  File "/usr/lib/python3/dist-packages/softwareproperties/shortcuts.py", line 40, in shortcut_handler
    return handler(shortcut, **kwargs)
  File "/usr/lib/python3/dist-packages/softwareproperties/ppa.py", line 82, in __init__
    if self.lpppa.publish_debug_symbols:
  File "/usr/lib/python3/dist-packages/softwareproperties/ppa.py", line 120, in lpppa
    self._lpppa = self.lpteam.getPPAByName(name=self.ppaname)
  File "/usr/lib/python3/dist-packages/softwareproperties/ppa.py", line 107, in lpteam
    self._lpteam = self.lp.people(self.teamname)
  File "/usr/lib/python3/dist-packages/softwareproperties/ppa.py", line 98, in lp
    self._lp = login_func("%s.%s" % (self.__module__, self.__class__.__name__),
  File "/usr/lib/python3/dist-packages/launchpadlib/launchpad.py", line 494, in login_anonymously
    return cls(
  File "/usr/lib/python3/dist-packages/launchpadlib/launchpad.py", line 230, in __init__
    super(Launchpad, self).__init__(
  File "/usr/lib/python3/dist-packages/lazr/restfulclient/resource.py", line 472, in __init__
    self._wadl = self._browser.get_wadl_application(self._root_uri)
  File "/usr/lib/python3/dist-packages/lazr/restfulclient/_browser.py", line 447, in get_wadl_application
    response, content = self._request(url, media_type=wadl_type)
  File "/usr/lib/python3/dist-packages/lazr/restfulclient/_browser.py", line 389, in _request
    response, content = self._request_and_retry(
  File "/usr/lib/python3/dist-packages/lazr/restfulclient/_browser.py", line 359, in _request_and_retry
    response, content = self._connection.request(
  File "/usr/lib/python3/dist-packages/httplib2/__init__.py", line 1578, in request
    conn = self.connections[conn_key] = connection_type(
  File "/usr/lib/python3/dist-packages/httplib2/__init__.py", line 1095, in __init__
    self.proxy_info = proxy_info("https")
  File "/usr/lib/python3/dist-packages/httplib2/__init__.py", line 926, in proxy_info_from_environment
    return proxy_info_from_url(url, method, noproxy=None)
  File "/usr/lib/python3/dist-packages/httplib2/__init__.py", line 950, in proxy_info_from_url
    port = int(port)
ValueError: invalid literal for int() with base 10: 'db8:f00::2]:3128'

Ubuntu Release:
# lsb_release -rd
Description: Ubuntu 22.04.2 LTS
Release: 22.04

Package version:
# apt-cache policy software-properties-common
software-properties-common:
  Installed: 0.99.22.6
  Candidate: 0.99.22.6
  Version table:
 *** 0.99.22.6 500
        500 http://archive.ubuntu.com/ubuntu jammy-updates/main amd64 Packages
        100 /var/lib/dpkg/status
     0.99.22 500
        500 http://archive.ubuntu.com/ubuntu jammy/main amd64 Packages

[Matt Clauson (mec-dotorg)]

On another reading of this, it looks like the issue may end up being in dependency (and upstream package) httplib2. I'd like a sanity check on that, and I'm willing to file tickets in other packages or upstream as soon as I have cycles. I'm buried in the middle of another project right now, but I wanted to get the issue documented for any other poor souls running into it in the future.