juju deploy --dry-run does not catch series error in bundle

[Nicolas Pochet]

When deploying (or applying a new config to an existing model) a bundle some might want to ensure that everything is correct.
To do so, we can use the --dry-run flag.
When doing so, juju does not validate the series as it does it without the --dry-run flag.
For example, if we take this simple bundle:

applications:
  ubuntu:
    charm: cs:ubuntu
    series: foo

The ubuntu charm does not have the foo option. If we try to validate the bundle with juju deploy --dry-run, we get the following output:

juju deploy bundle.yaml --dry-run
Resolving charm: cs:ubuntu
Changes to deploy bundle:
- upload charm cs:ubuntu-12 for series foo
- deploy application ubuntu on foo using cs:ubuntu-12

Everything seems to be fine according to juju. We can deploy to the foo series.
If we want to deploy, without dry-run, then we get the error that we expect:

juju deploy bundle.yaml
Resolving charm: cs:ubuntu
Executing changes:
- upload charm cs:ubuntu-12 for series foo
- deploy application ubuntu on foo using cs:ubuntu-12
ERROR cannot deploy bundle: series "foo" not supported by charm, supported series are: xenial,bionic,artful,trusty,precise

[Felipe Reyes (freyes)]

now that charmhub supports multiple bases this caveat becomes more important (to me), because in the CI we use a lot of "juju deploy --dry-run" to determine if a given bundle is "reasonably correct", and knowing if juju will find a charm to run in the desired architecture[0] and series is important.

 ~ $ cat bundle.yaml
series: jammy
applications:
  ubuntu:
    charm: ch:ubuntu
    num_units: 1
 ~ $ juju deploy --dry-run ./bundle.yaml
Located charm "ubuntu" in charm-hub, channel stable
Changes to deploy bundle:
- upload charm ubuntu from charm-hub for series jammy with architecture=amd64
- deploy application ubuntu from charm-hub on jammy
- add unit ubuntu/0 to new machine 0
 ~ $ juju deploy ./bundle.yaml
Located charm "ubuntu" in charm-hub, channel stable
Executing changes:
- upload charm ubuntu from charm-hub for series jammy with architecture=amd64
- deploy application ubuntu from charm-hub on jammy
ERROR cannot deploy bundle: series "jammy" not supported by charm, supported series are: focal, bionic, xenial, groovy

[0] OpenStack charms support amd64, arm64, ppc64el, s390x

[Canonical Juju QA Bot (juju-qa-bot)]

This Medium-priority bug has not been updated in 60 days, so we're marking it Low importance. If you believe this is incorrect, please update the importance.