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Oliver Tale-Yazdi authored(imported from https://github.com/paritytech/cumulus/pull/2157) ## Changes This MR refactores the XCMP, Parachains System and DMP pallets to use the [MessageQueue](https://github.com/paritytech/substrate/pull/12485) for delayed execution of incoming messages. The DMP pallet is entirely replaced by the MQ and thereby removed. This allows for PoV-bounded execution and resolves a number of issues that stem from the current work-around. All System Parachains adopt this change. The most important changes are in `primitives/core/src/lib.rs`, `parachains/common/src/process_xcm_message.rs`, `pallets/parachain-system/src/lib.rs`, `pallets/xcmp-queue/src/lib.rs` and the runtime configs. ### DMP Queue Pallet The pallet got removed and its logic refactored into parachain-system. Overweight message management can be done directly through the MQ pallet. Final undeployment migrations are provided by `cumulus_pallet_dmp_queue::UndeployDmpQueue` and `DeleteDmpQueue` that can be configured with an aux config trait like: ```rust parameter_types! { pub const DmpQueuePalletName: &'static str = \"DmpQueue\" < CHANGE ME; pub const RelayOrigin: AggregateMessageOrigin = AggregateMessageOrigin::Parent; } impl cumulus_pallet_dmp_queue::MigrationConfig for Runtime { type PalletName = DmpQueuePalletName; type DmpHandler = frame_support::traits::EnqueueWithOrigin<MessageQueue, RelayOrigin>; type DbWeight = <Runtime as frame_system::Config>::DbWeight; } // And adding them to your Migrations tuple: pub type Migrations = ( ... cumulus_pallet_dmp_queue::UndeployDmpQueue<Runtime>, cumulus_pallet_dmp_queue::DeleteDmpQueue<Runtime>, ); ``` ### XCMP Queue pallet Removed all dispatch queue functionality. Incoming XCMP messages are now either: Immediately handled if they are Signals, enqueued into the MQ pallet otherwise. New config items for the XCMP queue pallet: ```rust /// The actual queue implementation that retains the messages for later processing. type XcmpQueue: EnqueueMessage<ParaId>; /// How a XCM over HRMP from a sibling parachain should be processed. type XcmpProcessor: ProcessMessage<Origin = ParaId>; /// The maximal number of suspended XCMP channels at the same time. #[pallet::constant] type MaxInboundSuspended: Get<u32>; ``` How to configure those: ```rust // Use the MessageQueue pallet to store messages for later processing. The `TransformOrigin` is needed since // the MQ pallet itself operators on `AggregateMessageOrigin` but we want to enqueue `ParaId`s. type XcmpQueue = TransformOrigin<MessageQueue, AggregateMessageOrigin, ParaId, ParaIdToSibling>; // Process XCMP messages from siblings. This is type-safe to only accept `ParaId`s. They will be dispatched // with origin `Junction::Sibling(…)`. type XcmpProcessor = ProcessFromSibling< ProcessXcmMessage< AggregateMessageOrigin, xcm_executor::XcmExecutor<xcm_config::XcmConfig>, RuntimeCall, >, >; // Not really important what to choose here. Just something larger than the maximal number of channels. type MaxInboundSuspended = sp_core::ConstU32<1_000>; ``` The `InboundXcmpStatus` storage item was replaced by `InboundXcmpSuspended` since it now only tracks inbound queue suspension and no message indices anymore. Now only sends the most recent channel `Signals`, as all prio ones are out-dated anyway. ### Parachain System pallet For `DMP` messages instead of forwarding them to the `DMP` pallet, it now pushes them to the configured `DmpQueue`. The message processing which was triggered in `set_validation_data` is now being done by the MQ pallet `on_initialize`. XCMP messages are still handed off to the `XcmpMessageHandler` (XCMP-Queue pallet) - no change here. New config items for the parachain system pallet: ```rust /// Queues inbound downward messages for delayed processing. /// /// Analogous to the `XcmpQueue` of the XCMP queue pallet. type DmpQueue: EnqueueMessage<AggregateMessageOrigin>; ``` How to configure: ```rust /// Use the MQ pallet to store DMP messages for delayed processing. type DmpQueue = MessageQueue; ``` ## Message Flow The flow of messages on the parachain side. Messages come in from the left via the `Validation Data` and finally end up at the `Xcm Executor` on the right.  ## Further changes - Bumped the default suspension, drop and resume thresholds in `QueueConfigData::default()`. - `XcmpQueue::{suspend_xcm_execution, resume_xcm_execution}` errors when they would be a noop. - Properly validate the `QueueConfigData` before setting it. - Marked weight files as auto-generated so they wont auto-expand in the MR files view. - Move the `hypothetical` asserts to `frame_support` under the name `experimental_hypothetically` Questions: - [ ] What about the ugly `#[cfg(feature = \"runtime-benchmarks\")]` in the runtimes? Not sure how to best fix. Just having them like this makes tests fail that rely on the real message processor when the feature is enabled. - [ ] Need a good weight for `MessageQueueServiceWeight`. The scheduler already takes 80% so I put it to 10% but that is quite low. TODO: - [x] Remove c&p code after https://github.com/paritytech/polkadot/pull/6271 - [x] Use `HandleMessage` once it is public in Substrate - [x] fix `runtime-benchmarks` feature https://github.com/paritytech/polkadot/pull/6966 - [x] Benchmarks - [x] Tests - [ ] Migrate `InboundXcmpStatus` to `InboundXcmpSuspended` - [x] Possibly cleanup Migrations (DMP+XCMP) - [x] optional: create `TransformProcessMessageOrigin` in Substrate and replace `ProcessFromSibling` - [ ] Rerun weights on ref HW --------- Signed-off-by:Oliver Tale-Yazdi <[email protected]> Co-authored-by:
Liam Aharon <[email protected]> Co-authored-by:
joe petrowski <[email protected]> Co-authored-by:
Kian Paimani <[email protected]> Co-authored-by: command-bot <>