content sharing getting in the way of snap removal

[Harald Sitter]

snapd:
  Installed: 2.15.2ubuntu1
  Candidate: 2.15.2ubuntu1

fully up to date xenial

Supposedly to do with content sharing:

When installing a snap that employs content sharing it at some point will fail to remove old versions.
The only way to recover from this is to purge snapd and start from scratch.

example:

I have `kde-frameworks.snap` which provides a content slot. This slot is used by `kcalc.snap`. Once x4 of kcalc is meant to be installed (4th time one runs install with a changed verion) it would automatically remove x1, it fails to remove however.

$ sudo snap install --force-dangerous --devmode kcalc_0_amd64.snap
[sudo] password for me:
2016-09-27T13:26:38+02:00 INFO Waiting for snap-kcalc-x1.mount to stop.
2016-09-27T13:26:39+02:00 ERROR cannot remove snap file "kcalc", will retry in 3 mins: snap-kcalc-x1.mount failed to stop: timeout
2016-09-27T13:29:39+02:00 ERROR cannot remove snap file "kcalc", will retry in 3 mins: umount: /snap/kcalc/x1: not mounted
[-] Remove snap "kcalc" (x1) from the system

mount output after aborting this:
/var/lib/snapd/snaps/ubuntu-core_423.snap on /snap/ubuntu-core/423 type squashfs (ro,relatime)
/var/lib/snapd/snaps/kde-frameworks-5_x1.snap on /snap/kde-frameworks-5/x1 type squashfs (ro,relatime)
/var/lib/snapd/snaps/kcalc_x2.snap on /snap/kcalc/x2 type squashfs (ro,relatime)
/var/lib/snapd/snaps/kcalc_x3.snap on /snap/kcalc/x3 type squashfs (ro,relatime)
/var/lib/snapd/snaps/kde-frameworks-5_x2.snap on /snap/kde-frameworks-5/x2 type squashfs (ro,relatime)
/var/lib/snapd/snaps/kde-frameworks-5_x3.snap on /snap/kde-frameworks-5/x3 type squashfs (ro,relatime)
/var/lib/snapd/snaps/kcalc_x4.snap on /snap/kcalc/x4 type squashfs (ro,relatime)

mount output before:
/var/lib/snapd/snaps/ubuntu-core_423.snap on /snap/ubuntu-core/423 type squashfs (ro,relatime)
/var/lib/snapd/snaps/kde-frameworks-5_x1.snap on /snap/kde-frameworks-5/x1 type squashfs (ro,relatime)
/var/lib/snapd/snaps/kcalc_x1.snap on /snap/kcalc/x1 type squashfs (ro,relatime)
/var/lib/snapd/snaps/kcalc_x2.snap on /snap/kcalc/x2 type squashfs (ro,relatime)
/var/lib/snapd/snaps/kcalc_x3.snap on /snap/kcalc/x3 type squashfs (ro,relatime)
/var/lib/snapd/snaps/kde-frameworks-5_x2.snap on /snap/kde-frameworks-5/x2 type squashfs (ro,relatime)
/var/lib/snapd/snaps/kde-frameworks-5_x3.snap on /snap/kde-frameworks-5/x3 type squashfs (ro,relatime)

[Jamie Strandboge (jdstrand)]

Is this still an issue with 2.20?

[Launchpad Janitor (janitor)]

[Expired for snapd (Ubuntu) because there has been no activity for 60 days.]