[MQ pallet] Dont warn for low on_idle weight

[ggwpez]

The on_idle of the MQ pallet calls the service_queues function which prints a warning when it does not have enough weight to do anything.
Normally this is an issue since its called from on_initialize, but on_idle it should not print a defensive error.
It was introduced in #3844.

[gotnoshoeson]

Yo @ggwpez looking for a good-first-issue to jump into polkadot and contribute. Coming from Ethereum full-stack app development.

[gotnoshoeson]

So I see the defensive! getting thrown on line 1562. defensive!("Not enough weight to service a single message."); I'm thinking I can create a context parameter of where the service_queues is being called. fn service_queues(weight_limit: Weight, context: Context) If it's being called within on_initialize then pass "on_initialize" as the argument and it can continue with the current code. If "on_idle" is passed as context argument then it just returns Weight::zero(). Does this logic make sense? Or is there some other convention for doing something like this in Rust? Cheers!

[ggwpez]

Yo ggwpez looking for a good-first-issue to jump into polkadot and contribute. Coming from Ethereum full-stack app development.

Thanks, yes please go ahead.

fn service_queues(weight_limit: Weight, context: Context)

Yea that sounds good! I think we dont have a precedent case on how to handle this, but a small enum with two entries OnIdle and OnInitialize should work 😄