chromium browser deb to snap switch kills dist-upgrade

[Robert]

During the 16LTS to 18LTS (GUI) distribution upgrade I received a warning that the process couldn't connect to the snap store. I didn't have any snaps installed, so I continued with the distribution upgrade and everything worked OK.

During the 18LTS to 20LTS (GUI) distribution upgrade I received and accepted the same warning. As before I had no snaps installed. However, I did have Chromium browser installed, and as part of the distribution upgrade this tries to switch from being installed from deb to being installed from snap. At this point the distribution upgrade came to a complete halt. Also the desktop GUI became unresponsive, but it was possible to switch to a TTY console with (say) CTRL-ALT-F4, login, and execute commands.

The first time this happened I managed to recover the situation somehow, and proceeded to a working 20LTS installation (albeit with a few quirks). The second time it happened I was not, and ended up with a mish-mash of 18LTS and 20LTS that wouldn't boot to the desktop. Fortunately the second time I had made a disk image of the 18LTS system, and was able to go back to that. I removed Chromium, and trying the distribution upgrade again I was not issued with the snap store warning, and the process completed uneventfully.

BTW, I tried to report this problem using ubuntu-bug, but I hit this brick wall: https://bugs.launchpad.net/apport/+bug/1160316. Hence the manual report.

[Olivier Tilloy (osomon)]

Looking back at the upgrade logic, there is this:

    "Unable to contact the store, trying every minute for the next 30 minutes"

(see https://bazaar.launchpad.net/~chromium-team/chromium-browser/focal-stable/view/head:/debian/chromium-browser.preinst)

This might be acceptable in a normal update process, but maybe not in a dist upgrade?

Out of curiosity, do you know why your machine being upgraded wouldn't be able to reach the snap store? Did you disconnect from the network after all packages were downloaded, or did something else to that effect?

[Robert (birmingham-spider)]

The inability to access the snap store is a complete mystery to me. The message was displayed just /before/ gigabytes of distribution upgrade were downloaded and installed, and I was online the whole time. And this wasn't a once-off; I've seen it four times now.

When the deb/snap swap stalled, I left it to sort itself for a long time before I decided it really had stalled. It's possible that had I waited half an hour it would have continued normally, but there was no indication anything was happening.

[Olivier Tilloy (osomon)]

I am now testing this by dist-upgrading a 18.04 VM with chromium-browser installed to 20.04.

[Olivier Tilloy (osomon)]

Robert, on that upgraded system, are you able to access the snap store from the command line? E.g.:

    sudo snap install hello-world

[Olivier Tilloy (osomon)]

> I am now testing this by dist-upgrading a 18.04 VM with
> chromium-browser installed to 20.04.

Well the dist upgrade went well. I didn't get any warnings about connecting to the snap store. I did get a debconf dialog to warn of the deb->snap transition as expected, and the one glitch I observed is that the dialog didn't go away after accepting, until installing the snap was complete. That's not great UX, but the upgrade process went fine nevertheless.

[Robert (birmingham-spider)]

Thank you for trying; it's rather puzzling this one. I ran the snap command on the upgraded machine and got:

robert@samhain:~$ sudo snap install hello-world
[sudo] password for robert:
hello-world 6.4 from Canonical✓ installed
robert@samhain:~$ hello-world
ERROR: ld.so: object 'libgtk3-nocsd.so.0' from LD_PRELOAD cannot be preloaded (failed to map segment from shared object): ignored.
Hello World!
robert@samhain:~$

So not entirely smooth, but it looks like the snap store was accessible.