A cron job was running that started an "apt-get upgrade" while the dist-upgrade was running. Ouch.
Edited the <package>.postinst file that subsequently crashed, stopped cron, did a dist-upgrade, then removed and reinstalled the package in question. Everything works fine. This is the first distribution in years that handles suspend/resume robustly on my laptop - many thanks to whoever fixed the kernel.
Perhaps do-release-upgrade should suspend cron processing while upgrading?
If that is the intention, then it didn't work.
I will add the files if you still think it useful.
The entire error is a red herring, I now think.
A cron job was running that started an "apt-get upgrade" while the dist-upgrade was running. Ouch.
Edited the <package>.postinst file that subsequently crashed, stopped cron, did a dist-upgrade, then removed and reinstalled the package in question. Everything works fine. This is the first distribution in years that handles suspend/resume robustly on my laptop - many thanks to whoever fixed the kernel.
Perhaps do-release-upgrade should suspend cron processing while upgrading?
If that is the intention, then it didn't work.
I will add the files if you still think it useful.