Deploy to existing machine: "base does not match" even when series supported

[Jordan Barrett]

The setup is: I'm inside a model with a single machine "0" which is running ubuntu@22.04 / jammy. When I try deploy certain charms to this machine, this happens:
-------------------------------------------------------------------
$ juju deploy juju-dashboard d --to 0
Located charm "juju-dashboard" in charm-hub, revision 6
Deploying "d" from charm-hub charm "juju-dashboard", revision 6 in channel stable on ubuntu@20.04/stable
ERROR cannot add application "d": cannot deploy to machine 0: base does not match: unit has "ubuntu@20.04", machine has "ubuntu@22.04"
-------------------------------------------------------------------

However, the juju-dashboard charm supports jammy, so this deployment should work fine. It appears that it is asking Charmhub for the default series, trying to match this against the machine series, and failing when they don't match. Instead, we should read the machine series and request this series from Charmhub.

For now, a workaround is to specify --series:
    juju deploy juju-dashboard d --to 0 --series jammy

-------------------------------------------------------------------
$ juju version --all
version: 3.0.1-ubuntu-amd64
git-commit: deb94d4cac9efe42c0beee07a74f320fae0acd6b
-------------------------------------------------------------------

[Juan M. Tirado (tiradojm)]

Can we check this again?

[Vitaly Antonenko (anvial)]

I cannot reproduce this bug (3.0.3):
```
anvial@ubuntu-pc:~/Projects/juju-dev$ juju add-model m
Added 'm' model on localhost/localhost with credential 'localhost' for user 'admin'
anvial@ubuntu-pc:~/Projects/juju-dev$ juju add-machine --series jammy
created machine 0
anvial@ubuntu-pc:~/Projects/juju-dev$ juju status --watch 1s
anvial@ubuntu-pc:~/Projects/juju-dev$ juju deploy juju-dashboard d --to 0
Located charm "juju-dashboard" in charm-hub, revision 8
Deploying "d" from charm-hub charm "juju-dashboard", revision 8 in channel stable on ubuntu@22.04/stable
anvial@ubuntu-pc:~/Projects/juju-dev$
```

[Jordan Barrett (barrettj12)]

@anvial: that's because of a recent change to Charmhub where jammy is now the default base. We still get this bug if we try to deploy to an e.g. focal machine.
-----------------------------------------------------
$ juju add-machine --series focal
created machine 0
$ juju deploy juju-dashboard d --to 0
Located charm "juju-dashboard" in charm-hub, revision 8
Deploying "d" from charm-hub charm "juju-dashboard", revision 8 in channel stable on ubuntu@22.04/stable
ERROR cannot add application "d": cannot deploy to machine 0: base does not match: unit has "ubuntu@22.04", machine has "ubuntu@20.04"
-----------------------------------------------------