I hope I’m missing something, but there seems to be no way for a configure hook to verify the keys being set, nor to issue non-fatal warning.
The motivating instance is that a user misspelt
snap set mir-kiosk cursor=none
And instead typed
snap set mir-kiosk hidecursor=true
As that appears to work (it doesn’t report a problem) they didn’t realize their mistake and reported a bug.
What I’d like to be able to do is enumerate the keys set and issue a warning:
snap set mir-kiosk hidecursor=true
Warning: unsupported configuration key: hidecursor
Supported keys are:
cursor: The way the cursor is displayed. Can be "auto", "software" or "none"
vt: The virtual terminal to be used in daemon mode
daemon: Whether to run as a "daemon"
display-layout: Layout of outputs to select from mir-kiosk.display
Verifying snap configuration keys
snapctl requires the configuration key to be specified (there’s no equivalent of snap get mir-kiosk which lists all key-value pairs) so there is no way to enumerate unsupported keys.
Issuing warnings
Now, because of the possibility of keys supported in past or future versions of a snap, any “unsupported key” messages ought to be non-fatal. But the only way to get console output from a configure hook is to exit 1.
Have I missed a way to do this? Or a reason that it should not be possible?