Trying to install a snap from an unavailable channel shows candidates from other unavailable channels

[Paul Goins]

Hello,

A Juju charm I'm working with is attempting to install the prometheus-juju-exporter snap from the 3.4/stable branch, but is failing. The error message suggests that packages are installable from the candidate/beta/edge channels, but attempting to install from those also fails.

I'm uncertain whether there even _is_ a 3.4-series snap present for this particular snap - however, the bug is that the snap CLI is indicating that there is, and yet I cannot install it from the alternate channels it recommends.

Reproduction steps are as follows:

# This will fail, referring to candidate/beta/edge
sudo snap install --channel=3.4/stable prometheus-juju-exporter
# This will fail, referring to beta/edge
sudo snap install --channel=3.4/candidate prometheus-juju-exporter
# This will fail, referring to edge
sudo snap install --channel=3.4/beta prometheus-juju-exporter
# This will fail, referring to other tracks, including ones which don't show up under "snap info prometheus-juju-exporter"
sudo snap install --channel=3.4/edge prometheus-juju-exporter

Full output of the above example follows below:

ubuntu@juju-1:~$ sudo snap install --channel=3.4/stable prometheus-juju-exporter
error: snap "prometheus-juju-exporter" is not available on 3.4/stable but is available to install
       on the following channels:

       3.4/candidate snap install --channel=3.4/candidate prometheus-juju-exporter
       3.4/beta snap install --channel=3.4/beta prometheus-juju-exporter
       3.4/edge snap install --channel=3.4/edge prometheus-juju-exporter

       Please be mindful pre-release channels may include features not completely tested or
       implemented. Get more information with 'snap info prometheus-juju-exporter'.
ubuntu@juju-1:~$ sudo snap install --channel=3.4/candidate prometheus-juju-exporter
error: snap "prometheus-juju-exporter" is not available on 3.4/candidate but is available to
       install on the following channels:

       3.4/beta snap install --channel=3.4/beta prometheus-juju-exporter
       3.4/edge snap install --channel=3.4/edge prometheus-juju-exporter

       Get more information with 'snap info prometheus-juju-exporter'.
ubuntu@juju-1:~$ sudo snap install --channel=3.4/beta prometheus-juju-exporter
error: snap "prometheus-juju-exporter" is not available on 3.4/beta but is available to install on
       the following channels:

       3.4/edge snap install --channel=3.4/edge prometheus-juju-exporter

       Get more information with 'snap info prometheus-juju-exporter'.
ubuntu@juju-1:~$ sudo snap install --channel=3.4/edge prometheus-juju-exporter
error: snap "prometheus-juju-exporter" is not available on 3.4/edge but is available to install on
       the following tracks:

       latest/stable snap install --stable prometheus-juju-exporter
       latest/candidate snap install --candidate prometheus-juju-exporter
       latest/beta snap install --beta prometheus-juju-exporter
       latest/edge snap install --edge prometheus-juju-exporter
       3.3/candidate snap install --channel=3.3/candidate prometheus-juju-exporter
       3.3/beta snap install --channel=3.3/beta prometheus-juju-exporter
       3.3/edge snap install --channel=3.3/edge prometheus-juju-exporter
       3.1/candidate snap install --channel=3.1/candidate prometheus-juju-exporter
       3.1/beta snap install --channel=3.1/beta prometheus-juju-exporter
       3.1/edge snap install --channel=3.1/edge prometheus-juju-exporter
       3/stable snap install --channel=3 prometheus-juju-exporter
       3/candidate snap install --channel=3/candidate prometheus-juju-exporter
       3/beta snap install --channel=3/beta prometheus-juju-exporter
       3/edge snap install --channel=3/edge prometheus-juju-exporter
       2.9/stable snap install --channel=2.9 prometheus-juju-exporter
       2.9/candidate snap install --channel=2.9/candidate prometheus-juju-exporter
       2.9/beta snap install --channel=2.9/beta prometheus-juju-exporter
       2.9/edge snap install --channel=2.9/edge prometheus-juju-exporter
       2.8/stable snap install --channel=2.8 prometheus-juju-exporter
       2.8/candidate snap install --channel=2.8/candidate prometheus-juju-exporter
       2.8/beta snap install --channel=2.8/beta prometheus-juju-exporter
       2.8/edge snap install --channel=2.8/edge prometheus-juju-exporter

       Please be mindful that different tracks may include different features. Get more information
       with 'snap info prometheus-juju-exporter'.

[Paul Goins (vultaire)]

For the record, my snapd is version 2.61.3+22.04.