One of my snaps had an update last month and with it came 2 separate reports of data loss. The snap in question doesn’t do anything out of the ordinary, there’s no hooks that configure the application (aside from the default install hook for fonts made by the Gnome extension), and there’s been no similar reports in any other release of the application. To add on to this, the snap forces a minimum version of snapd that has Refresh App Awareness enabled, and both reports happened within 2 weeks of the snap being pushed, which would suggest the app was almost certainly not running at the time.
The impression I would have is that the usual upgrade mechanism failed to copy the entireity of the $SNAP_USER_DATA folder for some unknown reason. The log files for the application were reset after the upgrade, which are usually append only, and alongside it, the rest of the application data appeared to also be missing.
I though it’s best to raise awareness here, to see if any core snapd devs would be able to offer input in how to diagnose potential root cause, and importantly, see if it’s likely to occur with other snaps/users/etc.
Is there any advice that can be given for the users in the thread above?