dmp: Check that the para exist before delivering a message

[bkchr]

No description provided.

[bkchr]

/cmd prdoc --audience runtime_dev --bump patch

[bkontur]

for those failed rococo/westend benchmarks, for ToParachainDeliveryHelper e.g. here adding some EnsureForParachain implementation which does that paras::Heads::<Runtime>::insert(p, HeadData(p.encode().into())); should fix it (this is needed just for relaychains, which does dmp)

[bkontur]

there is also one place: https://github.com/paritytech/polkadot-sdk/blob/master/polkadot/runtime/parachains/src/hrmp.rs#L1886-L1898, I am not sure if this new Unroutable could happen in this place, maybe we could change that e.g.:

                // try to enqueue
		if let Err(error) =
			dmp::Pallet::<T>::queue_downward_message(&config, dest, notification_bytes)
		{
			// this should never happen unless the max downward message size is configured to a
			// jokingly small number or para is not registered/active.
			log::error!(
				target: "runtime::hrmp",
				"sending '{log_label}::notification_bytes' failed with error: {error:?}."
			);
			debug_assert!(false);
		}

[bkontur]

for those failed rococo/westend benchmarks, for ToParachainDeliveryHelper e.g. here adding some EnsureForParachain implementation which does that paras::Heads::<Runtime>::insert(p, HeadData(p.encode().into())); should fix it (this is needed just for relaychains, which does dmp)

let me fix this for you

[bkchr]

let me fix this for you

I already have it fixed locally :) Just need to fix more :D

[bkontur]

let me fix this for you

I already have it fixed locally :) Just need to fix more :D

:D :D nice, so at least please consider one small clean-up of my older code: #6714

[paritytech-workflow-stopper]

All GitHub workflows were cancelled due to failure one of the required jobs.
Failed workflow url: https://github.com/paritytech/polkadot-sdk/actions/runs/12099962839
Failed job name: run-frame-omni-bencher