Juju broken on macOS 11 Big Sur

[Joseph Borg]

panic: cannot determine host series: unknown series version 20

goroutine 1 [running]:
github.com/juju/os/series.mustHostSeries(0x2540be400, 0x7f72580)
 <email address hidden>/series/series.go:50 +0x65
github.com/juju/juju/api.init()
 github.com/juju/juju/api/certpool.go:19 +0x17f

I get the above error when I try to run any Juju command on Big Sur. I've tried to rebuild from brew.

[Ben Hoyt (benhoyt)]

Thanks for the report. Yes, this is not good -- looks like we have hard-coded the macOS versions in the code, and the Juju code panics on startup if we don't recognize it. See https://github.com/juju/os/blob/68703c0e39a22773a0517ca3f0e26e3154bc1c3b/series/series.go#L96

A fix for this will be straight forward, and I'm guessing it will go into the next versions (2.8.7 and 2.9-rc3).

[Ben Hoyt (benhoyt)]

Fix committed for 2.8: https://github.com/juju/juju/pull/12319 (we'll forward merge to the develop branch for 2.9 soon). As mentioned, this will be included in 2.8.7 coming out very soon, as well as 2.9 coming out in a few weeks. Or you should be able to pick it up off the edge snap in a few hours.

What version of Juju were you running, by the way?

[Ben Hoyt (benhoyt)]

Note that the fix above wasn't backwards compatible, as it pulled in changes from juju/os that would mean focal workloads were deployed when using Juju 2.8 if the charm defaulted to focal (a change in behavior). I've reverted this fix and am fixing properly now.

[Ben Hoyt (benhoyt)]

Updated fix: https://github.com/juju/juju/pull/12328

[Ben Hoyt (benhoyt)]

FWIW, I've also just committed a change to fix this issue once and for all -- so the juju client doesn't care what operating system series it runs on (whether known or not), so this won't happen in future when a new series comes out either. PR links:

* 2.8: https://github.com/juju/juju/pull/12341
* merged into develop (2.9): https://github.com/juju/juju/pull/12350