From 8c146a7c7133f00567c8b48277db79236dc6d751 Mon Sep 17 00:00:00 2001
From: Ankan <10196091+Ank4n@users.noreply.github.com>
Date: Thu, 7 Nov 2024 11:22:06 +0100
Subject: [PATCH] [pallet-staking] Add page info to `PayoutStarted` event
 (#5984)

fixes https://github.com/paritytech/polkadot-sdk/issues/5966

---------

Co-authored-by: Guillaume Thiolliere <gui.thiolliere@gmail.com>
---
 prdoc/pr_5984.prdoc                         | 14 ++++++++++++++
 substrate/frame/staking/src/pallet/impls.rs |  2 ++
 substrate/frame/staking/src/pallet/mod.rs   |  9 +++++++--
 substrate/frame/staking/src/tests.rs        |  6 ++++--
 4 files changed, 27 insertions(+), 4 deletions(-)
 create mode 100644 prdoc/pr_5984.prdoc

diff --git a/prdoc/pr_5984.prdoc b/prdoc/pr_5984.prdoc
new file mode 100644
index 000000000000..3b6651bac6b9
--- /dev/null
+++ b/prdoc/pr_5984.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: Add page information to staking::PayoutStarted event
+
+doc:
+  - audience: Runtime User
+    description: |
+      Adds page index that is claimed, and optional next page that can be claimed. If next is none, then the page is the
+      last one.
+
+crates:
+  - name: pallet-staking
+    bump: major
diff --git a/substrate/frame/staking/src/pallet/impls.rs b/substrate/frame/staking/src/pallet/impls.rs
index 649903741140..d3423d82769d 100644
--- a/substrate/frame/staking/src/pallet/impls.rs
+++ b/substrate/frame/staking/src/pallet/impls.rs
@@ -349,6 +349,8 @@ impl<T: Config> Pallet<T> {
 		Self::deposit_event(Event::<T>::PayoutStarted {
 			era_index: era,
 			validator_stash: stash.clone(),
+			page,
+			next: EraInfo::<T>::get_next_claimable_page(era, &stash, &ledger),
 		});
 
 		let mut total_imbalance = PositiveImbalanceOf::<T>::zero();
diff --git a/substrate/frame/staking/src/pallet/mod.rs b/substrate/frame/staking/src/pallet/mod.rs
index 28aa4f89b622..5210bef853b2 100644
--- a/substrate/frame/staking/src/pallet/mod.rs
+++ b/substrate/frame/staking/src/pallet/mod.rs
@@ -851,8 +851,13 @@ pub mod pallet {
 		StakingElectionFailed,
 		/// An account has stopped participating as either a validator or nominator.
 		Chilled { stash: T::AccountId },
-		/// The stakers' rewards are getting paid.
-		PayoutStarted { era_index: EraIndex, validator_stash: T::AccountId },
+		/// A Page of stakers rewards are getting paid. `next` is `None` if all pages are claimed.
+		PayoutStarted {
+			era_index: EraIndex,
+			validator_stash: T::AccountId,
+			page: Page,
+			next: Option<Page>,
+		},
 		/// A validator has set their preferences.
 		ValidatorPrefsSet { stash: T::AccountId, prefs: ValidatorPrefs },
 		/// Voters size limit reached.
diff --git a/substrate/frame/staking/src/tests.rs b/substrate/frame/staking/src/tests.rs
index 639f4096456f..d1dc6c3db659 100644
--- a/substrate/frame/staking/src/tests.rs
+++ b/substrate/frame/staking/src/tests.rs
@@ -3978,6 +3978,7 @@ fn test_multi_page_payout_stakers_by_page() {
 		assert!(matches!(
 			staking_events_since_last_call().as_slice(),
 			&[
+				Event::PayoutStarted { era_index: 1, validator_stash: 11, page: 0, next: Some(1) },
 				..,
 				Event::Rewarded { stash: 1063, dest: RewardDestination::Stash, amount: 111 },
 				Event::Rewarded { stash: 1064, dest: RewardDestination::Stash, amount: 111 },
@@ -4001,7 +4002,7 @@ fn test_multi_page_payout_stakers_by_page() {
 		assert!(matches!(
 			events.as_slice(),
 			&[
-				Event::PayoutStarted { era_index: 1, validator_stash: 11 },
+				Event::PayoutStarted { era_index: 1, validator_stash: 11, page: 1, next: None },
 				Event::Rewarded { stash: 1065, dest: RewardDestination::Stash, amount: 111 },
 				Event::Rewarded { stash: 1066, dest: RewardDestination::Stash, amount: 111 },
 				..
@@ -8011,7 +8012,8 @@ mod ledger_recovery {
 			assert_eq!(asset::staked::<Test>(&333), lock_333_before); // OK
 			assert_eq!(Bonded::<Test>::get(&333), Some(444)); // OK
 			assert!(Payee::<Test>::get(&333).is_some()); // OK
-												// however, ledger associated with its controller was killed.
+
+			// however, ledger associated with its controller was killed.
 			assert!(Ledger::<Test>::get(&444).is_none()); // NOK
 
 			// side effects on 444 - ledger, bonded, payee, lock should be completely removed.