Use Message Queue as DMP and XCMP dispatch queue (#1246)

(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.

![Untitled
(1)](https://github.com/paritytech/cumulus/assets/10380170/6cf8b377-88c9-4aed-96df-baace266e04d)

## 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 <oliver.tale-yazdi@parity.io>
Co-authored-by: Liam Aharon <liam.aharon@hotmail.com>
Co-authored-by: joe petrowski <25483142+joepetrowski@users.noreply.github.com>
Co-authored-by: Kian Paimani <5588131+kianenigma@users.noreply.github.com>
Co-authored-by: command-bot <>

cumulus/parachains/runtimes/starters/seedling/src/lib.rs

@@ -183,11 +183,13 @@ impl cumulus_pallet_solo_to_para::Config for Runtime {
 }
 
 impl cumulus_pallet_parachain_system::Config for Runtime {
+	type WeightInfo = ();
 	type RuntimeEvent = RuntimeEvent;
 	type OnSystemEvent = cumulus_pallet_solo_to_para::Pallet<Runtime>;
 	type SelfParaId = parachain_info::Pallet<Runtime>;
 	type OutboundXcmpMessageSource = ();
-	type DmpMessageHandler = ();
+	// Ignore all DMP messages by enqueueing them into `()`:
+	type DmpQueue = frame_support::traits::EnqueueWithOrigin<(), sp_core::ConstU8<0>>;
 	type ReservedDmpWeight = ();
 	type XcmpMessageHandler = ();
 	type ReservedXcmpWeight = ();

cumulus/parachains/runtimes/starters/shell/Cargo.toml

@@ -29,6 +29,7 @@ sp-session = { path = "../../../../../substrate/primitives/session", default-fea
 sp-std = { path = "../../../../../substrate/primitives/std", default-features = false}
 sp-transaction-pool = { path = "../../../../../substrate/primitives/transaction-pool", default-features = false}
 sp-version = { path = "../../../../../substrate/primitives/version", default-features = false}
+pallet-message-queue = { path = "../../../../../substrate/frame/message-queue", default-features = false }
 
 # Polkadot
 xcm = { package = "staging-xcm", path = "../../../../../polkadot/xcm", default-features = false}
@@ -59,6 +60,7 @@ std = [
 	"frame-system/std",
 	"frame-try-runtime?/std",
 	"pallet-aura/std",
+	"pallet-message-queue/std",
 	"pallet-timestamp/std",
 	"parachain-info/std",
 	"parachains-common/std",
@@ -89,6 +91,7 @@ try-runtime = [
 	"frame-system/try-runtime",
 	"frame-try-runtime/try-runtime",
 	"pallet-aura/try-runtime",
+	"pallet-message-queue/try-runtime",
 	"pallet-timestamp/try-runtime",
 	"parachain-info/try-runtime",
 	"sp-runtime/try-runtime",

cumulus/parachains/runtimes/starters/shell/src/lib.rs

@@ -33,6 +33,7 @@ pub mod xcm_config;
 
 use codec::{Decode, Encode};
 use cumulus_pallet_parachain_system::RelayNumberMonotonicallyIncreases;
+use cumulus_primitives_core::AggregateMessageOrigin;
 use frame_support::unsigned::TransactionValidityError;
 use scale_info::TypeInfo;
 use sp_api::impl_runtime_apis;
@@ -181,16 +182,17 @@ impl frame_system::Config for Runtime {
 }
 
 parameter_types! {
-	// We do anything the parent chain tells us in this runtime.
-	pub const ReservedDmpWeight: Weight = MAXIMUM_BLOCK_WEIGHT.saturating_div(2);
+	pub const RelayOrigin: AggregateMessageOrigin = AggregateMessageOrigin::Parent;
+	pub const ReservedDmpWeight: Weight = MAXIMUM_BLOCK_WEIGHT.saturating_div(4);
 }
 
 impl cumulus_pallet_parachain_system::Config for Runtime {
+	type WeightInfo = ();
 	type RuntimeEvent = RuntimeEvent;
 	type OnSystemEvent = ();
 	type SelfParaId = parachain_info::Pallet<Runtime>;
 	type OutboundXcmpMessageSource = ();
-	type DmpMessageHandler = cumulus_pallet_xcm::UnlimitedDmpExecution<Runtime>;
+	type DmpQueue = frame_support::traits::EnqueueWithOrigin<MessageQueue, RelayOrigin>;
 	type ReservedDmpWeight = ReservedDmpWeight;
 	type XcmpMessageHandler = ();
 	type ReservedXcmpWeight = ();
@@ -205,6 +207,32 @@ impl cumulus_pallet_parachain_system::Config for Runtime {
 
 impl parachain_info::Config for Runtime {}
 
+parameter_types! {
+	pub MessageQueueServiceWeight: Weight = Perbill::from_percent(35) * RuntimeBlockWeights::get().max_block;
+}
+
+impl pallet_message_queue::Config for Runtime {
+	type RuntimeEvent = RuntimeEvent;
+	type WeightInfo = ();
+	#[cfg(feature = "runtime-benchmarks")]
+	type MessageProcessor = pallet_message_queue::mock_helpers::NoopMessageProcessor<
+		cumulus_primitives_core::AggregateMessageOrigin,
+	>;
+	#[cfg(not(feature = "runtime-benchmarks"))]
+	type MessageProcessor = xcm_builder::ProcessXcmMessage<
+		AggregateMessageOrigin,
+		xcm_executor::XcmExecutor<xcm_config::XcmConfig>,
+		RuntimeCall,
+	>;
+	type Size = u32;
+	// These need to be configured to the XCMP pallet - if it is deployed.
+	type QueueChangeHandler = ();
+	type QueuePausedQuery = ();
+	type HeapSize = sp_core::ConstU32<{ 64 * 1024 }>;
+	type MaxStale = sp_core::ConstU32<8>;
+	type ServiceWeight = MessageQueueServiceWeight;
+}
+
 impl cumulus_pallet_aura_ext::Config for Runtime {}
 
 impl pallet_aura::Config for Runtime {
@@ -237,8 +265,8 @@ construct_runtime! {
 		},
 		ParachainInfo: parachain_info::{Pallet, Storage, Config<T>},
 
-		// DMP handler.
 		CumulusXcm: cumulus_pallet_xcm::{Pallet, Call, Storage, Event<T>, Origin},
+		MessageQueue: pallet_message_queue::{Pallet, Call, Storage, Event<T>},
 
 		Aura: pallet_aura::{Pallet, Storage, Config<T>},
 		AuraExt: cumulus_pallet_aura_ext::{Pallet, Storage, Config<T>},