Error starting a guix shell

[Zelphir Kaltstahl <zelphirkaltstahl@posteo.de>]

Hello Guix users!

Today I had a strange error, when I ran a `guix shell` command:

~~~~
(repl-version 0 1 1)
(exception %exception (non-self-quoting 140737175054176 "#<&message message: \"unsupported manifest format\">"))
~~~~

This happened with guix on foreign distro and that distro is a Xubuntu 22.04, 
which I recently upgraded from 20.04 -> 22.04. After that, I think today was the 
first time I ran that guix shell command. Because of the distribution upgrade, a 
lot of things can have changed.

This is how I ran the command:

I have an `env.bash` file:

~~~~
#!/usr/bin/env bash

set -Eeuxo pipefail

DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" > /dev/null 2>&1 && pwd)"

printf "script directory is: %s\n" "${DIR}"
guix time-machine \
      --channels="${DIR}/channels.scm" -- \
      shell \
      --development \
      --check \
      --manifest="${DIR}/manifest.scm"
~~~~

The `manifest.scm` file is:

~~~~
(specifications->manifest
  '("python"
    "python-requests"
    "python-docker"
    "python-websocket-client"
    "python-iniconfig"
    "python-pytest"
    "docker-compose"
    ))
~~~~

The `channels.scm` file is:

~~~~
(list (channel
         (name 'guix)
         (url"https://git.savannah.gnu.org/git/guix.git")
         (branch "master")
         (commit
           "dbf09879710aefe6cedd9ed975cc2b79df01b755")
         (introduction
           (make-channel-introduction
             "9edb3f66fd807b096b48283debdcddccfea34bad"
             (openpgp-fingerprint
               "BBB0 2DDF 2CEA F6A8 0D1D  E643 A2A0 6DF2 A33A 54FA")))))
~~~~

However, I unfortunately already updated the `channels.scm` file using `guix 
describe --format=channels > channels.scm`, so the above file is not the file, 
with which I had the error, and I have no idea what the channel was before.

When I had the error, I simply ran `bash guix-env/env.bash`, to activate the 
shell. Then I got an error and guix told me about a log file, some `*.log.gz` 
file. That one I copied out of the GNU store directory and opened the contained 
text file. It contained the error I wrote above.

I am aware, that without the exact `channels.scm` file, this might be 
irreproducible. Sorry about it! When I hit the error, I thought: "Ahh well, 
quickly update guix and see if it solves it." and I also did the guix describe 
thingy to update the channel file, because my primary goal was to get the guix 
shell working again. Only later I thought of still needed that old file, in 
order to make a proper report. Sorry! After doing the following, it worked again:

~~~~
sudo -i
guix pull && guix package -u
(Ctrl+d)
guix pull && guix package -u
guix describe --format=channels > channels.scm
~~~~

My question now is, what could have caused the error? I thought, that, if I keep 
`channels.scm` the same, I would get a reproducible environment, assuming, that 
guix itself does not change behavior. Also the OS upgrade can of course have 
interfered and I would not be able to tell. But perhaps my strategy to get 
reproducible shells is not as safe as I thought? ("Can I still run in this 
environment/shell in 5 years? In 10? With the same results?")

Best regards and apologies again for the not so precise information,
Zelphir

-- 
repositories:https://notabug.org/ZelphirKaltstahl