Comment 16 for bug 2008248

Hi,

Got affected by this bug with `keystone-saml-mellon` and `grafana-agent-k8s` charms which have different builds and revisions for 22.04 and 20.04 during upgrade Focal-Ussuri -> Jammy-Yoga. There I'm using Juju 2.9.45.

I reproduced the isssue `octavia-disk-retrofit` and `keystone-saml-mellon` charms. I'm using Juju controller 2.9.49:
```
juju deploy octavia --series focal --channel='yoga/stable' octavia2
juju deploy octavia-diskimage-retrofit --series focal --channel='yoga/stable' octavia-diskimage-retrofit2
juju add-relation octavia-diskimage-retrofit2 octavia2
juju upgrade-series 42 prepare jammy
WARNING: This command will mark machine "42" as being upgraded to series "jammy".
This operation cannot be reverted or canceled once started.
Units running on the machine will also be upgraded. These units include:
  - octavia-diskimage-retrofit2/0
  - octavia2/0

Leadership for the following applications will be pinned and not
subject to change until the "complete" command is run:
  - octavia-diskimage-retrofit2
  - octavia2

Continue [y/N]?y
ERROR charm "octavia-diskimage-retrofit" does not support jammy, force not used
```

```
juju deploy keystone-saml-mellon --channel="yoga/stable" --series="focal"
juju deploy keystone --series=focal --config openstack-origin=cloud:focal-yoga
juju add-relation keystone-saml-mellon keystone

juju upgrade-series 41 prepare jammy
WARNING: This command will mark machine "41" as being upgraded to series "jammy".
This operation cannot be reverted or canceled once started.
Units running on the machine will also be upgraded. These units include:
  - keystone-saml-mellon/0
  - keystone/0

Leadership for the following applications will be pinned and not
subject to change until the "complete" command is run:
  - keystone
  - keystone-saml-mellon

Continue [y/N]?y
ERROR charm "keystone-saml-mellon" does not support jammy, force not used
```

So it still reproduces. It is a bummer for series upgrades.

FTR, how I upgraded my keystone.
1. Had my keystone-saml-mellon on revision that supports only Focal
2. Ran `juju upgrade-series <machine> prepare jammy` with `--force` to ignore charm doesn't support Jammy
3. `do-release-upgrade` on the machine
4. Ran `juju upgrade-series <machine> complete`.
5. `keystone-saml-mellon` went to error state because of broken dependencies. Helped it with `juju resolved --no-retry keystone-saml-mellon/XX`
6. Upgrade is completed
7. After all keystone units are upgraded to jammy, finally refresh `keystone-saml-mellon` to revision that supports Jammy `juju refresh keystone-saml-mellon --revision=98`

Now having my `keystone-saml-mellon` in blocked state with "Ready for do-release-upgrade and reboot. Set complete when finished." but I guess it is lesser of evils.