Update Scheduler to Support Relay Chain Block Number Provider

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

@@ -604,11 +604,13 @@ parameter_types! {
 #[cfg(not(feature = "runtime-benchmarks"))]
 parameter_types! {
 	pub const MaxScheduledPerBlock: u32 = 50;
+	pub const MaxScheduledBlocks: u32 = 50;
 }
 
 #[cfg(feature = "runtime-benchmarks")]
 parameter_types! {
 	pub const MaxScheduledPerBlock: u32 = 200;
+	pub const MaxScheduledBlocks: u32 = 200;
 }
 
 impl pallet_scheduler::Config for Runtime {
@@ -622,6 +624,8 @@ 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;
 }
 
 parameter_types! {

polkadot/runtime/rococo/src/lib.rs

@@ -231,6 +231,7 @@ 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 NoPreimagePostponement: Option<u32> = Some(10);
 }
 
@@ -331,6 +332,8 @@ 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;
 }
 
 parameter_types! {

polkadot/runtime/westend/src/lib.rs

@@ -232,6 +232,7 @@ 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 NoPreimagePostponement: Option<u32> = Some(10);
 }
 
@@ -248,6 +249,8 @@ 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;
 }
 
 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

@@ -499,6 +499,11 @@ 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>;
 }
 
 impl pallet_glutton::Config for Runtime {

substrate/frame/democracy/src/tests.rs

@@ -106,6 +106,8 @@ impl pallet_scheduler::Config for Test {
 	type WeightInfo = ();
 	type OriginPrivilegeCmp = EqualPrivilegeOnly;
 	type Preimages = ();
+	type BlockNumberProvider = frame_system::Pallet<Test>;
+	type MaxScheduledBlocks = ConstU32<100>;
 }
 
 #[derive_impl(pallet_balances::config_preludes::TestDefaultConfig)]

substrate/frame/referenda/src/mock.rs

@@ -81,6 +81,8 @@ impl pallet_scheduler::Config for Test {
 	type WeightInfo = ();
 	type OriginPrivilegeCmp = EqualPrivilegeOnly;
 	type Preimages = Preimage;
+	type BlockNumberProvider = frame_system::Pallet<Test>;
+	type MaxScheduledBlocks = ConstU32<100>;
 }
 #[derive_impl(pallet_balances::config_preludes::TestDefaultConfig)]
 impl pallet_balances::Config for Test {

substrate/frame/scheduler/src/benchmarking.rs

@@ -22,17 +22,20 @@ use alloc::vec;
 use frame_benchmarking::v1::{account, benchmarks, BenchmarkError};
 use frame_support::{
 	ensure,
+	testing_prelude::*,
 	traits::{schedule::Priority, BoundedInline},
 	weights::WeightMeter,
 };
-use frame_system::{pallet_prelude::BlockNumberFor, RawOrigin};
+use frame_system::RawOrigin;
 
 use crate::Pallet as Scheduler;
 use frame_system::{Call as SystemCall, EventRecord};
 
 const SEED: u32 = 0;
 
-const BLOCK_NUMBER: u32 = 2;
+fn block_number<T: Config>() -> u32 {
+	T::MaxScheduledBlocks::get()
+}
 
 type SystemOrigin<T> = <T as frame_system::Config>::RuntimeOrigin;
 
@@ -44,17 +47,23 @@ 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 vec = Vec::<BlockNumberFor<T>>::new();
+	for i in 0..n {
+		vec.push(i.into());
+	}
+	let bounded_vec = BoundedVec::try_from(vec).unwrap();
+	Queue::<T>::put::<BoundedVec<_, _>>(bounded_vec);
+}
+
 /// 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 {
@@ -137,17 +146,19 @@ fn make_origin<T: Config>(signed: bool) -> <T as Config>::PalletsOrigin {
 benchmarks! {
 	// `service_agendas` when no work is done.
 	service_agendas_base {
-		let now = BlockNumberFor::<T>::from(BLOCK_NUMBER);
-		IncompleteSince::<T>::put(now - One::one());
+		let now = BlockNumberFor::<T>::from(block_number::<T>());
+		Queue::<T>::put::<BoundedVec<_, _>>(bounded_vec![now + One::one()]);
 	}: {
 		Scheduler::<T>::service_agendas(&mut WeightMeter::new(), now, 0);
 	} verify {
-		assert_eq!(IncompleteSince::<T>::get(), Some(now - One::one()));
+		let expected: BoundedVec<BlockNumberFor<T>, T::MaxScheduledBlocks> =
+			bounded_vec![now + One::one()];
+		assert_eq!(Queue::<T>::get(), expected);
 	}
 
 	// `service_agenda` when no work is done.
 	service_agenda_base {
-		let now = BLOCK_NUMBER.into();
+		let now = block_number::<T>().into();
 		let s in 0 .. T::MaxScheduledPerBlock::get();
 		fill_schedule::<T>(now, s)?;
 		let mut executed = 0;
@@ -160,7 +171,7 @@ benchmarks! {
 	// `service_task` when the task is a non-periodic, non-named, non-fetched call which is not
 	// dispatched (e.g. due to being overweight).
 	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());
@@ -178,7 +189,7 @@ benchmarks! {
 	}]
 	service_task_fetched {
 		let s in (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());
@@ -190,7 +201,7 @@ benchmarks! {
 	// `service_task` when the task is a non-periodic, named, non-fetched call which is not
 	// dispatched (e.g. due to being overweight).
 	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());
@@ -202,7 +213,7 @@ benchmarks! {
 	// `service_task` when the task is a periodic, non-named, non-fetched call which is not
 	// dispatched (e.g. due to being overweight).
 	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());
@@ -235,26 +246,32 @@ benchmarks! {
 
 	schedule {
 		let s in 0 .. (T::MaxScheduledPerBlock::get() - 1);
-		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);
 	}: _(RawOrigin::Root, when, periodic, priority, call)
 	verify {
 		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"
+		);
 	}
 
 	cancel {
 		let s in 1 .. T::MaxScheduledPerBlock::get();
-		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)?;
@@ -273,31 +290,41 @@ 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"
+		);
 	}
 
 	schedule_named {
 		let s in 0 .. (T::MaxScheduledPerBlock::get() - 1);
 		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);
 	}: _(RawOrigin::Root, id, when, periodic, priority, call)
 	verify {
 		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"
+		);
 	}
 
 	cancel_named {
 		let s in 1 .. T::MaxScheduledPerBlock::get();
-		let when = BLOCK_NUMBER.into();
+		let when = (block_number::<T>() - 1).into();
 
 		fill_schedule::<T>(when, s)?;
+		fill_queue::<T>(T::MaxScheduledBlocks::get());
 	}: _(RawOrigin::Root, u32_to_name(0))
 	verify {
 		ensure!(
@@ -313,11 +340,15 @@ 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"
+		);
 	}
 
 	schedule_retry {
 		let s in 1 .. 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);
@@ -341,7 +372,7 @@ benchmarks! {
 
 	set_retry {
 		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);
@@ -361,7 +392,7 @@ benchmarks! {
 
 	set_retry_named {
 		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);
@@ -381,7 +412,7 @@ benchmarks! {
 
 	cancel_retry {
 		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);
@@ -399,7 +430,7 @@ benchmarks! {
 
 	cancel_retry_named {
 		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);