Enable async backing on asset-hub-rococo

cumulus/parachains/runtimes/assets/asset-hub-rococo/Cargo.toml

@@ -77,6 +77,7 @@ cumulus-pallet-parachain-system = { path = "../../../../pallets/parachain-system
 cumulus-pallet-session-benchmarking = { path = "../../../../pallets/session-benchmarking", default-features = false }
 cumulus-pallet-xcm = { path = "../../../../pallets/xcm", default-features = false }
 cumulus-pallet-xcmp-queue = { path = "../../../../pallets/xcmp-queue", default-features = false, features = ["bridging"] }
+cumulus-primitives-aura = { path = "../../../../primitives/aura", default-features = false }
 cumulus-primitives-core = { path = "../../../../primitives/core", default-features = false }
 cumulus-primitives-utility = { path = "../../../../primitives/utility", default-features = false }
 pallet-collator-selection = { path = "../../../../pallets/collator-selection", default-features = false }
@@ -190,6 +191,7 @@ std = [
 	"cumulus-pallet-session-benchmarking/std",
 	"cumulus-pallet-xcm/std",
 	"cumulus-pallet-xcmp-queue/std",
+	"cumulus-primitives-aura/std", # TODO: guide is missing this step
 	"cumulus-primitives-core/std",
 	"cumulus-primitives-utility/std",
 	"frame-benchmarking?/std",

cumulus/parachains/runtimes/assets/asset-hub-rococo/src/lib.rs

@@ -33,7 +33,7 @@ use assets_common::{
 	matching::{FromNetwork, FromSiblingParachain},
 	AssetIdForTrustBackedAssetsConvert, MultiLocationForAssetId,
 };
-use cumulus_pallet_parachain_system::RelayNumberStrictlyIncreases;
+use cumulus_pallet_parachain_system::RelayNumberMonotonicallyIncreases;
 use cumulus_primitives_core::AggregateMessageOrigin;
 use snowbridge_rococo_common::EthereumNetwork;
 use sp_api::impl_runtime_apis;
@@ -62,7 +62,7 @@ use frame_support::{
 		ConstU128, ConstU32, ConstU64, ConstU8, EitherOfDiverse, Equals, InstanceFilter,
 		TransformOrigin,
 	},
-	weights::{ConstantMultiplier, Weight},
+	weights::{constants::WEIGHT_REF_TIME_PER_SECOND, ConstantMultiplier, Weight},
 	BoundedVec, PalletId,
 };
 use frame_system::{
@@ -75,10 +75,9 @@ pub use parachains_common as common;
 use parachains_common::{
 	impls::DealWithFees,
 	message_queue::{NarrowOriginToSibling, ParaIdToSibling},
-	rococo::{consensus::*, currency::*, fee::WeightToFee},
+	rococo::{currency::*, fee::WeightToFee},
 	AccountId, AssetIdForTrustBackedAssets, AuraId, Balance, BlockNumber, Hash, Header, Nonce,
-	Signature, AVERAGE_ON_INITIALIZE_RATIO, DAYS, HOURS, MAXIMUM_BLOCK_WEIGHT,
-	NORMAL_DISPATCH_RATIO, SLOT_DURATION,
+	Signature, AVERAGE_ON_INITIALIZE_RATIO, DAYS, HOURS, NORMAL_DISPATCH_RATIO,
 };
 
 use sp_runtime::{Perbill, RuntimeDebug};
@@ -137,6 +136,29 @@ pub fn native_version() -> NativeVersion {
 	NativeVersion { runtime_version: VERSION, can_author_with: Default::default() }
 }
 
+const MAXIMUM_BLOCK_WEIGHT: Weight = Weight::from_parts(
+	WEIGHT_REF_TIME_PER_SECOND.saturating_div(2),
+	cumulus_primitives_core::relay_chain::MAX_POV_SIZE as u64,
+);
+
+/// Maximum number of blocks simultaneously accepted by the Runtime, not yet included
+/// into the relay chain.
+const UNINCLUDED_SEGMENT_CAPACITY: u32 = 3;
+/// How many parachain blocks are processed by the relay chain per parent. Limits the
+/// number of blocks authored per slot.
+const BLOCK_PROCESSING_VELOCITY: u32 = 1;
+/// Relay chain slot duration, in milliseconds.
+const RELAY_CHAIN_SLOT_DURATION_MILLIS: u32 = 6000;
+
+/// This determines the average expected block time that we are targeting.
+/// Blocks will be produced at a minimum duration defined by `SLOT_DURATION`.
+/// `SLOT_DURATION` is picked up by `pallet_timestamp` which is in turn picked
+/// up by `pallet_aura` to implement `fn slot_duration()`.
+///
+/// Change this to adjust the block time.
+pub const MILLISECS_PER_BLOCK: u64 = 6000; // TODO: See if we make 6s blocks.
+pub const SLOT_DURATION: u64 = MILLISECS_PER_BLOCK;
+
 parameter_types! {
 	pub const Version: RuntimeVersion = VERSION;
 	pub RuntimeBlockLength: BlockLength =
@@ -185,6 +207,9 @@ impl pallet_timestamp::Config for Runtime {
 	/// A timestamp: milliseconds since the unix epoch.
 	type Moment = u64;
 	type OnTimestampSet = Aura;
+	#[cfg(feature = "experimental")]
+	type MinimumPeriod = ConstU64<0>;
+	#[cfg(not(feature = "experimental"))]
 	type MinimumPeriod = ConstU64<{ SLOT_DURATION / 2 }>;
 	type WeightInfo = weights::pallet_timestamp::WeightInfo<Runtime>;
 }
@@ -620,15 +645,17 @@ impl cumulus_pallet_parachain_system::Config for Runtime {
 	type OutboundXcmpMessageSource = XcmpQueue;
 	type XcmpMessageHandler = XcmpQueue;
 	type ReservedXcmpWeight = ReservedXcmpWeight;
-	type CheckAssociatedRelayNumber = RelayNumberStrictlyIncreases;
-	type ConsensusHook = cumulus_pallet_aura_ext::FixedVelocityConsensusHook<
-		Runtime,
-		RELAY_CHAIN_SLOT_DURATION_MILLIS,
-		BLOCK_PROCESSING_VELOCITY,
-		UNINCLUDED_SEGMENT_CAPACITY,
-	>;
+	type CheckAssociatedRelayNumber = RelayNumberMonotonicallyIncreases;
+	type ConsensusHook = ConsensusHook;
 }
 
+type ConsensusHook = cumulus_pallet_aura_ext::FixedVelocityConsensusHook<
+	Runtime,
+	RELAY_CHAIN_SLOT_DURATION_MILLIS,
+	BLOCK_PROCESSING_VELOCITY,
+	UNINCLUDED_SEGMENT_CAPACITY,
+>;
+
 parameter_types! {
 	pub MessageQueueServiceWeight: Weight = Perbill::from_percent(35) * RuntimeBlockWeights::get().max_block;
 }
@@ -712,9 +739,11 @@ impl pallet_aura::Config for Runtime {
 	type AuthorityId = AuraId;
 	type DisabledValidators = ();
 	type MaxAuthorities = ConstU32<100_000>;
-	type AllowMultipleBlocksPerSlot = ConstBool<false>;
+	// TODO: should this be true? Guide says false, but see:
+	// https://github.com/paritytech/polkadot-sdk/pull/1619/files#diff-17c0e44911184254502a1d0b157c58e706eaa938cd0b1fe34c0456e541066a2fR234
+	type AllowMultipleBlocksPerSlot = ConstBool<true>;
 	#[cfg(feature = "experimental")]
-	type SlotDuration = pallet_aura::MinimumPeriodTimesTwo<Self>;
+	type SlotDuration = ConstU64<SLOT_DURATION>;
 }
 
 parameter_types! {
@@ -1059,14 +1088,24 @@ mod benches {
 impl_runtime_apis! {
 	impl sp_consensus_aura::AuraApi<Block, AuraId> for Runtime {
 		fn slot_duration() -> sp_consensus_aura::SlotDuration {
-			sp_consensus_aura::SlotDuration::from_millis(Aura::slot_duration())
+			sp_consensus_aura::SlotDuration::from_millis(SLOT_DURATION)
 		}
 
 		fn authorities() -> Vec<AuraId> {
 			Aura::authorities().into_inner()
 		}
 	}
 
+	// TODO: Step 3.2 seems redundant?
+	impl cumulus_primitives_aura::AuraUnincludedSegmentApi<Block> for Runtime {
+		fn can_build_upon(
+			included_hash: <Block as BlockT>::Hash,
+			slot: cumulus_primitives_aura::Slot,
+		) -> bool {
+			ConsensusHook::can_build_upon(included_hash, slot)
+		}
+	}
+
 	impl sp_api::Core<Block> for Runtime {
 		fn version() -> RuntimeVersion {
 			VERSION

cumulus/polkadot-parachain/src/service.rs

@@ -1410,7 +1410,9 @@ where
 	<<AuraId as AppCrypto>::Pair as Pair>::Signature:
 		TryFrom<Vec<u8>> + std::hash::Hash + sp_runtime::traits::Member + Codec,
 {
-	start_node_impl::<RuntimeApi, _, _, _>(
+	// TODO: is this right? Seems okay since asset hub node is a "shell" node. Can Kusama start
+	// using this right away?
+	start_basic_lookahead_node_impl::<RuntimeApi, _, _, _>(
 		parachain_config,
 		polkadot_config,
 		collator_options,