Comment 4 for bug 1978139

Hi Frank,

After trying a few things, I've been able to reproduce the crash. Whether the snap refresh occurred through a manual refresh or through subiquity screen does not seem to make a difference.

I believe that you can work around the issue and move forward with your testing by connecting again to the installer through SSH _after_ the refresh is finished (or use the client on /dev/tty1 is that is an option for you).
Please let me know otherwise, I can probably help find another way to do the testing.

Details and investigation:
-------------------------

It seems that after the snap refresh, the clients that were connected through SSH (or maybe other means?) don't reload properly.

In my example:
3447 is the version of the snap after refresh
3314 is the version of the snap before refresh

$ pgrep -a python3
2205 /snap/subiquity/3447/usr/bin/python3.8 /snap/subiquity/3447/usr/bin/subiquity
2221 /snap/subiquity/3447/usr/bin/python3.8 -m subiquity.cmd.server
2242 /snap/subiquity/3447/usr/bin/python3.8 -m subiquity
2431 /snap/subiquity/3447/usr/bin/python3.8 -m subiquity

PID 2205 is the client running on /dev/tty/1
PID 2221 is the server (forked from the client running on /dev/tty/1 - I think)
PID 2242 is a client that has been connected through SSH since _before_ the refresh
PID 2431 is a client that connected through SSH _after_ the refresh

Looking at the environment for each client we have:

$ strings /proc/2205/environ | grep -e 3447 -e 3314
PYTHON=/snap/subiquity/3447/usr/bin/python3.8
SNAP_USER_DATA=/root/snap/subiquity/3447
SUBIQUITY_ROOT=/snap/subiquity/3447
SNAP_REVISION=3447
SNAP_DATA=/var/snap/subiquity/3447
PWD=/var/snap/subiquity/3447
SNAP=/snap/subiquity/3447
PYTHONPATH=/snap/subiquity/3447/lib/python3.8/site-packages

$ strings /proc/2242/environ | grep -e 3447 -e 3314
PYTHON=/snap/subiquity/3447/usr/bin/python3.8
SNAP_USER_DATA=/root/snap/subiquity/3447
SUBIQUITY_ROOT=/snap/subiquity/3447
SNAP_REVISION=3447
PATH=/snap/subiquity/3314/bin:/snap/subiquity/3314/usr/bin:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/snap/bin
APPORT_DATA_DIR=/snap/subiquity/3314/share/apport
SNAP_DATA=/var/snap/subiquity/3447
PYTHONPATH=:/snap/subiquity/3314/lib/python3.8/site-packages:/snap/subiquity/3447/lib/python3.8/site-packages
SNAP=/snap/subiquity/3447

$ strings /proc/2431/environ | grep -e 3447 -e 3314
PYTHON=/snap/subiquity/3447/usr/bin/python3.8
SNAP_USER_DATA=/root/snap/subiquity/3447
SUBIQUITY_ROOT=/snap/subiquity/3447
SNAP_REVISION=3447
SNAP_DATA=/var/snap/subiquity/3447
SNAP=/snap/subiquity/3447
PYTHONPATH=:/snap/subiquity/3447/lib/python3.8/site-packages

As shown above, 2242 ends up with a broken environment, making it mix up things from the old and new snap.

Thanks,
Olivier