Interesting, I was able to reproduce this issue today.
Started a 20.04 instance. Using juju 2.8.13 client, bootstrapped 2.8.5 and deployed the old ubuntu-plus charm with only bionic as a series. Then did an upgrade of juju which went right to 2.9.42 on the controller. Upgraded the model and tried the refresh.
$ juju upgrade-charm ubuntu-plus --path ./ubuntu-plus
Added charm "local:bionic/ubuntu-plus-1" to the model.
ERROR missing base name or channel not valid (not valid)
Interesting, I was able to reproduce this issue today.
Started a 20.04 instance. Using juju 2.8.13 client, bootstrapped 2.8.5 and deployed the old ubuntu-plus charm with only bionic as a series. Then did an upgrade of juju which went right to 2.9.42 on the controller. Upgraded the model and tried the refresh.
$ juju upgrade-charm ubuntu-plus --path ./ubuntu-plus bionic/ ubuntu- plus-1" to the model.
Added charm "local:
ERROR missing base name or channel not valid (not valid)
"charm-origin" : { bionic/ ubuntu- plus-0" ,
"source" : "local",
"type" : "charm",
"id" : "local:
"hash" : "",
"revision" : 0,
"platform" : {
"os" : "ubuntu",
"series" : "bionic"
}
}
Using a 2.9.42 client does not reproduce the problem