Update Pallet Referenda to support Block Number Provider (#6338)

This PR introduces BlockNumberProvider config for the referenda pallet.
closes part of #6297

Polkadot address: 12GyGD3QhT4i2JJpNzvMf96sxxBLWymz4RdGCxRH5Rj5agKW

---------

Co-authored-by: muharem <[email protected]>

Author: dharjeezy

cumulus/parachains/runtimes/collectives/collectives-westend/src/ambassador/mod.rs

@@ -154,6 +154,7 @@ impl pallet_referenda::Config<AmbassadorReferendaInstance> for Runtime {
 	type AlarmInterval = AlarmInterval;
 	type Tracks = tracks::TracksInfo;
 	type Preimages = Preimage;
+	type BlockNumberProvider = System;
 }
 
 parameter_types! {

cumulus/parachains/runtimes/collectives/collectives-westend/src/fellowship/mod.rs

@@ -106,6 +106,7 @@ impl pallet_referenda::Config<FellowshipReferendaInstance> for Runtime {
 	type AlarmInterval = ConstU32<1>;
 	type Tracks = tracks::TracksInfo;
 	type Preimages = Preimage;
+	type BlockNumberProvider = crate::System;
 }
 
 pub type FellowshipCollectiveInstance = pallet_ranked_collective::Instance1;

polkadot/runtime/rococo/src/governance/fellowship.rs

@@ -308,6 +308,7 @@ impl pallet_referenda::Config<FellowshipReferendaInstance> for Runtime {
 	type AlarmInterval = AlarmInterval;
 	type Tracks = TracksInfo;
 	type Preimages = Preimage;
+	type BlockNumberProvider = System;
 }
 
 pub type FellowshipCollectiveInstance = pallet_ranked_collective::Instance1;

polkadot/runtime/rococo/src/governance/mod.rs

@@ -90,4 +90,5 @@ impl pallet_referenda::Config for Runtime {
 	type AlarmInterval = AlarmInterval;
 	type Tracks = TracksInfo;
 	type Preimages = Preimage;
+	type BlockNumberProvider = System;
 }

polkadot/runtime/westend/src/governance/mod.rs

@@ -94,4 +94,5 @@ impl pallet_referenda::Config for Runtime {
 	type AlarmInterval = AlarmInterval;
 	type Tracks = TracksInfo;
 	type Preimages = Preimage;
+	type BlockNumberProvider = System;
 }

prdoc/pr_6338.prdoc

@@ -0,0 +1,14 @@
+# Schema: Polkadot SDK PRDoc Schema (prdoc) v1.0.0
+# See doc at https://raw.githubusercontent.com/paritytech/polkadot-sdk/master/prdoc/schema_user.json
+
+title: Update Referenda to Support Block Number Provider
+
+doc:
+  - audience: Runtime Dev
+    description: |
+      This PR makes the referenda pallet uses the relay chain as a block provider for a parachain on a regular schedule.
+      To migrate existing referenda implementations, simply add `type BlockNumberProvider = System` to have the same behavior as before.
+
+crates:
+- name: pallet-referenda
+  bump: major

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

@@ -1073,6 +1073,7 @@ impl pallet_referenda::Config for Runtime {
 	type AlarmInterval = AlarmInterval;
 	type Tracks = TracksInfo;
 	type Preimages = Preimage;
+	type BlockNumberProvider = System;
 }
 
 impl pallet_referenda::Config<pallet_referenda::Instance2> for Runtime {
@@ -1093,6 +1094,7 @@ impl pallet_referenda::Config<pallet_referenda::Instance2> for Runtime {
 	type AlarmInterval = AlarmInterval;
 	type Tracks = TracksInfo;
 	type Preimages = Preimage;
+	type BlockNumberProvider = System;
 }
 
 impl pallet_ranked_collective::Config for Runtime {

substrate/frame/referenda/src/benchmarking.rs

@@ -33,6 +33,10 @@ use sp_runtime::traits::Bounded as ArithBounded;
 
 const SEED: u32 = 0;
 
+fn set_block_number<T: Config<I>, I: 'static>(n: BlockNumberFor<T, I>) {
+	<T as Config<I>>::BlockNumberProvider::set_block_number(n);
+}
+
 fn assert_last_event<T: Config<I>, I: 'static>(generic_event: <T as Config<I>>::RuntimeEvent) {
 	frame_system::Pallet::<T>::assert_last_event(generic_event.into());
 }
@@ -151,30 +155,28 @@ fn make_failing<T: Config<I>, I: 'static>(index: ReferendumIndex) {
 fn skip_prepare_period<T: Config<I>, I: 'static>(index: ReferendumIndex) {
 	let status = Referenda::<T, I>::ensure_ongoing(index).unwrap();
 	let prepare_period_over = status.submitted + info::<T, I>(index).prepare_period;
-	frame_system::Pallet::<T>::set_block_number(prepare_period_over);
+	set_block_number::<T, I>(prepare_period_over);
 }
 
 fn skip_decision_period<T: Config<I>, I: 'static>(index: ReferendumIndex) {
 	let status = Referenda::<T, I>::ensure_ongoing(index).unwrap();
 	let decision_period_over = status.deciding.unwrap().since + info::<T, I>(index).decision_period;
-	frame_system::Pallet::<T>::set_block_number(decision_period_over);
+	set_block_number::<T, I>(decision_period_over);
 }
 
 fn skip_confirm_period<T: Config<I>, I: 'static>(index: ReferendumIndex) {
 	let status = Referenda::<T, I>::ensure_ongoing(index).unwrap();
 	let confirm_period_over = status.deciding.unwrap().confirming.unwrap();
-	frame_system::Pallet::<T>::set_block_number(confirm_period_over);
+	set_block_number::<T, I>(confirm_period_over);
 }
 
 fn skip_timeout_period<T: Config<I>, I: 'static>(index: ReferendumIndex) {
 	let status = Referenda::<T, I>::ensure_ongoing(index).unwrap();
 	let timeout_period_over = status.submitted + T::UndecidingTimeout::get();
-	frame_system::Pallet::<T>::set_block_number(timeout_period_over);
+	set_block_number::<T, I>(timeout_period_over);
 }
 
-fn alarm_time<T: Config<I>, I: 'static>(
-	index: ReferendumIndex,
-) -> frame_system::pallet_prelude::BlockNumberFor<T> {
+fn alarm_time<T: Config<I>, I: 'static>(index: ReferendumIndex) -> BlockNumberFor<T, I> {
 	let status = Referenda::<T, I>::ensure_ongoing(index).unwrap();
 	status.alarm.unwrap().0
 }