Update Scheduler to Support Relay Chain Block Number Provider

cumulus/parachains/runtimes/collectives/collectives-westend/src/lib.rs

@@ -610,11 +610,15 @@ parameter_types! {
 #[cfg(not(feature = "runtime-benchmarks"))]
 parameter_types! {
 	pub const MaxScheduledPerBlock: u32 = 50;
+	pub const MaxScheduledBlocks: u32 = 50;
+	pub const MaxStaleTaskAge: u32 = 10;
 }
 
 #[cfg(feature = "runtime-benchmarks")]
 parameter_types! {
 	pub const MaxScheduledPerBlock: u32 = 200;
+	pub const MaxScheduledBlocks: u32 = 200;
+	pub const MaxStaleTaskAge: u32 = 40;
 }
 
 impl pallet_scheduler::Config for Runtime {
@@ -628,6 +632,9 @@ impl pallet_scheduler::Config for Runtime {
 	type WeightInfo = weights::pallet_scheduler::WeightInfo<Runtime>;
 	type OriginPrivilegeCmp = EqualOrGreatestRootCmp;
 	type Preimages = Preimage;
+	type BlockNumberProvider = frame_system::Pallet<Runtime>;
+	type MaxScheduledBlocks = MaxScheduledBlocks;
+	type MaxStaleTaskAge = MaxStaleTaskAge;
 }
 
 parameter_types! {

polkadot/runtime/rococo/src/lib.rs

@@ -244,6 +244,8 @@ parameter_types! {
 	pub MaximumSchedulerWeight: Weight = Perbill::from_percent(80) *
 		BlockWeights::get().max_block;
 	pub const MaxScheduledPerBlock: u32 = 50;
+	pub const MaxScheduledBlocks: u32 = 50;
+	pub const MaxStaleTaskAge: u32 = 10;
 	pub const NoPreimagePostponement: Option<u32> = Some(10);
 }
 
@@ -344,6 +346,9 @@ impl pallet_scheduler::Config for Runtime {
 	type WeightInfo = weights::pallet_scheduler::WeightInfo<Runtime>;
 	type OriginPrivilegeCmp = OriginPrivilegeCmp;
 	type Preimages = Preimage;
+	type BlockNumberProvider = frame_system::Pallet<Runtime>;
+	type MaxScheduledBlocks = MaxScheduledBlocks;
+	type MaxStaleTaskAge = MaxStaleTaskAge;
 }
 
 parameter_types! {

polkadot/runtime/westend/src/lib.rs

@@ -234,6 +234,8 @@ parameter_types! {
 	pub MaximumSchedulerWeight: frame_support::weights::Weight = Perbill::from_percent(80) *
 		BlockWeights::get().max_block;
 	pub const MaxScheduledPerBlock: u32 = 50;
+	pub const MaxScheduledBlocks: u32 = 50;
+	pub const MaxStaleTaskAge: u32 = 10;
 	pub const NoPreimagePostponement: Option<u32> = Some(10);
 }
 
@@ -250,6 +252,9 @@ impl pallet_scheduler::Config for Runtime {
 	type WeightInfo = weights::pallet_scheduler::WeightInfo<Runtime>;
 	type OriginPrivilegeCmp = frame_support::traits::EqualPrivilegeOnly;
 	type Preimages = Preimage;
+	type BlockNumberProvider = frame_system::Pallet<Runtime>;
+	type MaxScheduledBlocks = MaxScheduledBlocks;
+	type MaxStaleTaskAge = MaxStaleTaskAge;
 }
 
 parameter_types! {

prdoc/pr_6362.prdoc

@@ -0,0 +1,23 @@
+title: Update Scheduler to Support Relay Chain Block Number Provider
+
+doc:
+  - audience: Runtime Dev
+    description: |
+      This PR adds the ability for the Scheduler pallet to specify its source of the block number.
+      This is needed for the scheduler pallet to work on a parachain which does not produce blocks
+      on a regular schedule, thus can use the relay chain as a block provider. Because blocks are
+      not produced regularly, we cannot make the assumption that the block number increases 
+      monotonically, and thus have a new logic via a `Queue` to handle multiple blocks with valid 
+      agenda passed between them.
+
+      This change only needs a migration for the `Queue`:
+      1. If the `BlockNumberProvider` continues to use the system pallet's block number
+      2. When a pallet deployed on the relay chain is moved to a parachain, but still uses the 
+      relay chain's block number
+
+      However, we would need migrations if the deployed pallets are upgraded on an existing parachain,
+      and the `BlockNumberProvider` uses the relay chain block number.  
+
+crates:
+  - name: pallet-scheduler
+    bump: major

substrate/bin/node/runtime/src/lib.rs

@@ -504,6 +504,12 @@ impl pallet_scheduler::Config for Runtime {
 	type WeightInfo = pallet_scheduler::weights::SubstrateWeight<Runtime>;
 	type OriginPrivilegeCmp = EqualPrivilegeOnly;
 	type Preimages = Preimage;
+	type BlockNumberProvider = frame_system::Pallet<Runtime>;
+	#[cfg(feature = "runtime-benchmarks")]
+	type MaxScheduledBlocks = ConstU32<512>;
+	#[cfg(not(feature = "runtime-benchmarks"))]
+	type MaxScheduledBlocks = ConstU32<50>;
+	type MaxStaleTaskAge = ConstU32<10>;
 }
 
 impl pallet_glutton::Config for Runtime {

substrate/frame/democracy/src/tests.rs

@@ -106,6 +106,9 @@ impl pallet_scheduler::Config for Test {
 	type WeightInfo = ();
 	type OriginPrivilegeCmp = EqualPrivilegeOnly;
 	type Preimages = ();
+	type BlockNumberProvider = frame_system::Pallet<Test>;
+	type MaxScheduledBlocks = ConstU32<100>;
+	type MaxStaleTaskAge = ConstU64<10>;
 }
 
 #[derive_impl(pallet_balances::config_preludes::TestDefaultConfig)]

substrate/frame/referenda/src/mock.rs

@@ -81,6 +81,9 @@ impl pallet_scheduler::Config for Test {
 	type WeightInfo = ();
 	type OriginPrivilegeCmp = EqualPrivilegeOnly;
 	type Preimages = Preimage;
+	type BlockNumberProvider = frame_system::Pallet<Test>;
+	type MaxScheduledBlocks = ConstU32<100>;
+	type MaxStaleTaskAge = ConstU64<10>;
 }
 #[derive_impl(pallet_balances::config_preludes::TestDefaultConfig)]
 impl pallet_balances::Config for Test {

substrate/frame/scheduler/src/benchmarking.rs

@@ -21,6 +21,7 @@ use alloc::vec;
 use frame_benchmarking::v2::*;
 use frame_support::{
 	ensure,
+	storage::bounded_btree_set::BoundedBTreeSet,
 	traits::{schedule::Priority, BoundedInline},
 	weights::WeightMeter,
 };
@@ -32,7 +33,10 @@ type SystemCall<T> = frame_system::Call<T>;
 type SystemOrigin<T> = <T as frame_system::Config>::RuntimeOrigin;
 
 const SEED: u32 = 0;
-const BLOCK_NUMBER: u32 = 2;
+
+fn block_number<T: Config>() -> u32 {
+	T::MaxScheduledBlocks::get()
+}
 
 fn assert_last_event<T: Config>(generic_event: <T as Config>::RuntimeEvent) {
 	let events = frame_system::Pallet::<T>::events();
@@ -42,17 +46,22 @@ fn assert_last_event<T: Config>(generic_event: <T as Config>::RuntimeEvent) {
 	assert_eq!(event, &system_event);
 }
 
+fn fill_queue<T: Config>(n: u32) {
+	let mut btree_set = BoundedBTreeSet::<BlockNumberFor<T>, T::MaxScheduledBlocks>::default();
+	for i in 0..n {
+		btree_set.try_insert(i.into()).unwrap();
+	}
+	Queue::<T>::put(btree_set);
+}
+
 /// Add `n` items to the schedule.
 ///
 /// For `resolved`:
 /// - `
 /// - `None`: aborted (hash without preimage)
 /// - `Some(true)`: hash resolves into call if possible, plain call otherwise
 /// - `Some(false)`: plain call
-fn fill_schedule<T: Config>(
-	when: frame_system::pallet_prelude::BlockNumberFor<T>,
-	n: u32,
-) -> Result<(), &'static str> {
+fn fill_schedule<T: Config>(when: BlockNumberFor<T>, n: u32) -> Result<(), &'static str> {
 	let t = DispatchTime::At(when);
 	let origin: <T as Config>::PalletsOrigin = frame_system::RawOrigin::Root.into();
 	for i in 0..n {
@@ -136,26 +145,31 @@ fn make_origin<T: Config>(signed: bool) -> <T as Config>::PalletsOrigin {
 mod benchmarks {
 	use super::*;
 
-	// `service_agendas` when no work is done.
+	// `service_agenda` when no work is done.
 	#[benchmark]
 	fn service_agendas_base() {
-		let now = BLOCK_NUMBER.into();
-		IncompleteSince::<T>::put(now - One::one());
+		let now = BlockNumberFor::<T>::from(block_number::<T>());
+		let mut set = BoundedBTreeSet::<_, _>::default();
+		set.try_insert(now + One::one()).unwrap(); // Insert the element
+		Queue::<T>::put(set);
 
 		#[block]
 		{
 			Pallet::<T>::service_agendas(&mut WeightMeter::new(), now, 0);
 		}
 
-		assert_eq!(IncompleteSince::<T>::get(), Some(now - One::one()));
+		let mut expected_set =
+			BoundedBTreeSet::<BlockNumberFor<T>, T::MaxScheduledBlocks>::default();
+		expected_set.try_insert(now + One::one()).unwrap();
+		assert_eq!(Queue::<T>::get(), expected_set);
 	}
 
 	// `service_agenda` when no work is done.
 	#[benchmark]
 	fn service_agenda_base(
 		s: Linear<0, { T::MaxScheduledPerBlock::get() }>,
 	) -> Result<(), BenchmarkError> {
-		let now = BLOCK_NUMBER.into();
+		let now = block_number::<T>().into();
 		fill_schedule::<T>(now, s)?;
 		let mut executed = 0;
 
@@ -173,7 +187,7 @@ mod benchmarks {
 	// dispatched (e.g. due to being overweight).
 	#[benchmark]
 	fn service_task_base() {
-		let now = BLOCK_NUMBER.into();
+		let now = block_number::<T>().into();
 		let task = make_task::<T>(false, false, false, None, 0);
 		// prevent any tasks from actually being executed as we only want the surrounding weight.
 		let mut counter = WeightMeter::with_limit(Weight::zero());
@@ -196,7 +210,7 @@ mod benchmarks {
 	fn service_task_fetched(
 		s: Linear<{ BoundedInline::bound() as u32 }, { T::Preimages::MAX_LENGTH as u32 }>,
 	) {
-		let now = BLOCK_NUMBER.into();
+		let now = block_number::<T>().into();
 		let task = make_task::<T>(false, false, false, Some(s), 0);
 		// prevent any tasks from actually being executed as we only want the surrounding weight.
 		let mut counter = WeightMeter::with_limit(Weight::zero());
@@ -214,7 +228,7 @@ mod benchmarks {
 	// dispatched (e.g. due to being overweight).
 	#[benchmark]
 	fn service_task_named() {
-		let now = BLOCK_NUMBER.into();
+		let now = block_number::<T>().into();
 		let task = make_task::<T>(false, true, false, None, 0);
 		// prevent any tasks from actually being executed as we only want the surrounding weight.
 		let mut counter = WeightMeter::with_limit(Weight::zero());
@@ -232,7 +246,7 @@ mod benchmarks {
 	// dispatched (e.g. due to being overweight).
 	#[benchmark]
 	fn service_task_periodic() {
-		let now = BLOCK_NUMBER.into();
+		let now = block_number::<T>().into();
 		let task = make_task::<T>(true, false, false, None, 0);
 		// prevent any tasks from actually being executed as we only want the surrounding weight.
 		let mut counter = WeightMeter::with_limit(Weight::zero());
@@ -286,27 +300,33 @@ mod benchmarks {
 	fn schedule(
 		s: Linear<0, { T::MaxScheduledPerBlock::get() - 1 }>,
 	) -> Result<(), BenchmarkError> {
-		let when = BLOCK_NUMBER.into();
+		let when = block_number::<T>().into();
 		let periodic = Some((BlockNumberFor::<T>::one(), 100));
 		let priority = 0;
 		// Essentially a no-op call.
 		let call = Box::new(SystemCall::set_storage { items: vec![] }.into());
 
 		fill_schedule::<T>(when, s)?;
+		fill_queue::<T>(T::MaxScheduledBlocks::get() - 1);
 
 		#[extrinsic_call]
 		_(RawOrigin::Root, when, periodic, priority, call);
 
-		ensure!(Agenda::<T>::get(when).len() == s as usize + 1, "didn't add to schedule");
+		ensure!(Agenda::<T>::get(when).len() == (s + 1) as usize, "didn't add to schedule");
+		ensure!(
+			Queue::<T>::get().len() == T::MaxScheduledBlocks::get() as usize,
+			"didn't add to queue"
+		);
 
 		Ok(())
 	}
 
 	#[benchmark]
 	fn cancel(s: Linear<1, { T::MaxScheduledPerBlock::get() }>) -> Result<(), BenchmarkError> {
-		let when = BLOCK_NUMBER.into();
+		let when = (block_number::<T>() - 1).into();
 
 		fill_schedule::<T>(when, s)?;
+		fill_queue::<T>(T::MaxScheduledBlocks::get());
 		assert_eq!(Agenda::<T>::get(when).len(), s as usize);
 		let schedule_origin =
 			T::ScheduleOrigin::try_successful_origin().map_err(|_| BenchmarkError::Weightless)?;
@@ -327,6 +347,10 @@ mod benchmarks {
 			s > 1 || Agenda::<T>::get(when).len() == 0,
 			"remove from schedule if only 1 task scheduled for `when`"
 		);
+		ensure!(
+			s > 1 || Queue::<T>::get().len() == T::MaxScheduledBlocks::get() as usize - 1,
+			"didn't remove from queue"
+		);
 
 		Ok(())
 	}
@@ -336,18 +360,23 @@ mod benchmarks {
 		s: Linear<0, { T::MaxScheduledPerBlock::get() - 1 }>,
 	) -> Result<(), BenchmarkError> {
 		let id = u32_to_name(s);
-		let when = BLOCK_NUMBER.into();
+		let when = block_number::<T>().into();
 		let periodic = Some((BlockNumberFor::<T>::one(), 100));
 		let priority = 0;
 		// Essentially a no-op call.
 		let call = Box::new(SystemCall::set_storage { items: vec![] }.into());
 
 		fill_schedule::<T>(when, s)?;
+		fill_queue::<T>(T::MaxScheduledBlocks::get() - 1);
 
 		#[extrinsic_call]
 		_(RawOrigin::Root, id, when, periodic, priority, call);
 
-		ensure!(Agenda::<T>::get(when).len() == s as usize + 1, "didn't add to schedule");
+		ensure!(Agenda::<T>::get(when).len() == (s + 1) as usize, "didn't add to schedule");
+		ensure!(
+			Queue::<T>::get().len() == T::MaxScheduledBlocks::get() as usize,
+			"didn't add to queue"
+		);
 
 		Ok(())
 	}
@@ -356,9 +385,10 @@ mod benchmarks {
 	fn cancel_named(
 		s: Linear<1, { T::MaxScheduledPerBlock::get() }>,
 	) -> Result<(), BenchmarkError> {
-		let when = BLOCK_NUMBER.into();
+		let when = (block_number::<T>() - 1).into();
 
 		fill_schedule::<T>(when, s)?;
+		fill_queue::<T>(T::MaxScheduledBlocks::get());
 
 		#[extrinsic_call]
 		_(RawOrigin::Root, u32_to_name(0));
@@ -376,6 +406,10 @@ mod benchmarks {
 			s > 1 || Agenda::<T>::get(when).len() == 0,
 			"remove from schedule if only 1 task scheduled for `when`"
 		);
+		ensure!(
+			s > 1 || Queue::<T>::get().len() == T::MaxScheduledBlocks::get() as usize - 1,
+			"didn't remove from queue"
+		);
 
 		Ok(())
 	}
@@ -384,7 +418,7 @@ mod benchmarks {
 	fn schedule_retry(
 		s: Linear<1, { T::MaxScheduledPerBlock::get() }>,
 	) -> Result<(), BenchmarkError> {
-		let when = BLOCK_NUMBER.into();
+		let when = block_number::<T>().into();
 
 		fill_schedule::<T>(when, s)?;
 		let name = u32_to_name(s - 1);
@@ -420,7 +454,7 @@ mod benchmarks {
 	#[benchmark]
 	fn set_retry() -> Result<(), BenchmarkError> {
 		let s = T::MaxScheduledPerBlock::get();
-		let when = BLOCK_NUMBER.into();
+		let when = block_number::<T>().into();
 
 		fill_schedule::<T>(when, s)?;
 		let name = u32_to_name(s - 1);
@@ -445,7 +479,7 @@ mod benchmarks {
 	#[benchmark]
 	fn set_retry_named() -> Result<(), BenchmarkError> {
 		let s = T::MaxScheduledPerBlock::get();
-		let when = BLOCK_NUMBER.into();
+		let when = block_number::<T>().into();
 
 		fill_schedule::<T>(when, s)?;
 		let name = u32_to_name(s - 1);
@@ -470,7 +504,7 @@ mod benchmarks {
 	#[benchmark]
 	fn cancel_retry() -> Result<(), BenchmarkError> {
 		let s = T::MaxScheduledPerBlock::get();
-		let when = BLOCK_NUMBER.into();
+		let when = block_number::<T>().into();
 
 		fill_schedule::<T>(when, s)?;
 		let name = u32_to_name(s - 1);
@@ -491,7 +525,7 @@ mod benchmarks {
 	#[benchmark]
 	fn cancel_retry_named() -> Result<(), BenchmarkError> {
 		let s = T::MaxScheduledPerBlock::get();
-		let when = BLOCK_NUMBER.into();
+		let when = block_number::<T>().into();
 
 		fill_schedule::<T>(when, s)?;
 		let name = u32_to_name(s - 1);