edit runtime: broadcast errors not being displayed to user

[oliver-sanders]

Broadcasts can fail due to invalid values, e.g:

$ cylc broadcast generic -n root -s 'run mode = simulation'
IllegalValueError: (type=option) run mode = simulation
$ echo $?
1

$ cylc broadcast generic -s 'execution retry delays = a*b'
IllegalValueError: (type=list) execution retry delays = a*b - (invalid literal for int() with base 10: 'a')
$ echo $?
1

These errors don't seem to be getting through to the UI (either in dev or production mode).

[MetRonnie]

I think this is cylc/cylc-flow#6429

[oliver-sanders]

After a bit of digging, the broadcast command does not report issues back in the GraphQL errors field because it supports mixed results where some broadcasts worked and others did not.

Instead, broadcast reports back lists of cycle points / namespaces which were valid, vs ones which were not. I have put up a draft cylc-flow PR to extend this to also cover settings (the example in the OP). The Edit Runtime form will need to inspect the result returned by the broadcast mutation in order to highlight any parts of the broadcast which could not be enacted.