"Label X can only be set by Rust team members" when label doesn't exist

[tgross35]

It seems like trying to label something if it doesn't exist gives an insufficient permissions error, rather than some sort of "label not found" error which would make more sense. Example:

rust-lang/rust#115719 (comment)

Also from that example, maybe labels should be checked case insensitive

[ehuss]

I think the issue there is just the case-sensitivity check for permissions. Generally, GitHub is case-insensitive for labels, but the triagebot code here is not. I believe glob supports case-insensitive matching, and a PR to update that would be welcome.

[tgross35]

Thanks, I made the matching case insensistive in #1722. I still think the message could be improved - even if someone does @rustbot label +definitely-doesnt-exist it should say that the label doesn't exist rather than that permissions aren't sufficient