Distro 1.40: possible regression in distro.codename()

[capsalad]

Calls to distro.codename() worked as expected in 1.30, but in 1.40 I'm seeing what amounts to truncated output.

Python 3.6.7 on Ubuntu 18.04

1.30 Bionic Beaver
1.40 bionic

Python 3.7.x on Ubuntu 18.10

1.30 Cosmic Cuttlefish
1.40 cosmic

Python 3.7.3 on Ubuntu 19.04

1.30 Disco Dingo
1.40 disco

Python 3.8.2 on Ubuntu 20.04

1.40 focal

I note a possibly breaking change in /etc/os-release, which currently looks like this:

NAME="Ubuntu"
VERSION="20.04 LTS (Focal Fossa)"
ID=ubuntu
ID_LIKE=debian
PRETTY_NAME="Ubuntu 20.04 LTS"
VERSION_ID="20.04"
HOME_URL="https://www.ubuntu.com/"
SUPPORT_URL="https://help.ubuntu.com/"
BUG_REPORT_URL="https://bugs.launchpad.net/ubuntu/"
PRIVACY_POLICY_URL="https://www.ubuntu.com/legal/terms-and-policies/privacy-policy"
VERSION_CODENAME=focal
UBUNTU_CODENAME=focal

Output of lsb_release -a:

No LSB modules are available.
Distributor ID: Ubuntu
Description: Ubuntu 20.04 LTS
Release: 20.04
Codename: focal

From the documentation, I thought that, on most Linux distros at least, distro.codename() should produce results identical to awk -F '[()]' '/VERSION=/ {print $2}' /etc/os-release. Is this no longer the case?

[albertodonato]

This also breaks compatibility between platform.linux_distribution and distro.linux_distribution:

>>> platform.linux_distribution(), distro.linux_distribution()
(('Ubuntu', '18.04', 'bionic'), ('Ubuntu', '18.04', 'Bionic Beaver'))

[HorlogeSkynet]

You are right, it looks like #230 broke this, and thus the compatibility shim with platform.linux_distribution.
Unfortunately, test cases verifying distro.linux_distribution behavior were (and still are) based on Ubuntu 14.04 materials, which do not contain VERSION_CODENAME attribute (so in this case the distribution "id" still comes from VERSION parsing).
distro.linux_distribution method has been deprecated in distro v1.6.0 (see #296), but I think we should fix this regression anyway as this module is still considered as a drop-in alternative to defunct platform.linux_distribution method.