From 489fc9ddc092f1fad2876551b4a3254096bc29d8 Mon Sep 17 00:00:00 2001
From: giuseppere <giuseppe.re@parity.io>
Date: Thu, 19 Dec 2024 11:10:12 +0100
Subject: [PATCH] remove unused `page_size` fn arg + fix tests

---
 substrate/frame/staking/src/lib.rs      | 3 +--
 substrate/frame/staking/src/tests.rs    | 3 ++-
 substrate/primitives/staking/src/lib.rs | 7 ++++---
 3 files changed, 7 insertions(+), 6 deletions(-)

diff --git a/substrate/frame/staking/src/lib.rs b/substrate/frame/staking/src/lib.rs
index 5ee0aaea7708..2bec5eab3fc3 100644
--- a/substrate/frame/staking/src/lib.rs
+++ b/substrate/frame/staking/src/lib.rs
@@ -1200,8 +1200,7 @@ impl<T: Config> EraInfo<T> {
 			.defensive_saturating_add((page_size as usize).defensive_saturating_sub(1))
 			.saturating_div(page_size as usize);
 
-		let (exposure_metadata, exposure_pages) =
-			exposure.into_pages::<T::MaxExposurePageSize>(page_size);
+		let (exposure_metadata, exposure_pages) = exposure.into_pages::<T::MaxExposurePageSize>();
 		defensive_assert!(exposure_pages.len() == expected_page_count, "unexpected page count");
 
 		<ErasStakersOverview<T>>::insert(era, &validator, &exposure_metadata);
diff --git a/substrate/frame/staking/src/tests.rs b/substrate/frame/staking/src/tests.rs
index 1e9a06e8be9d..8422b355dad4 100644
--- a/substrate/frame/staking/src/tests.rs
+++ b/substrate/frame/staking/src/tests.rs
@@ -6574,10 +6574,11 @@ fn can_page_exposure() {
 		Exposure { total: total_stake, own: own_stake, others };
 
 	// when
+	MaxExposurePageSize::set(3);
 	let (exposure_metadata, exposure_page): (
 		PagedExposureMetadata<Balance>,
 		Vec<ExposurePage<AccountId, Balance, MaxExposurePageSize>>,
-	) = exposure.clone().into_pages::<MaxExposurePageSize>(3);
+	) = exposure.clone().into_pages::<MaxExposurePageSize>();
 
 	// then
 	// 7 pages of nominators.
diff --git a/substrate/primitives/staking/src/lib.rs b/substrate/primitives/staking/src/lib.rs
index fe7895ab5bc3..a9e14dc5858a 100644
--- a/substrate/primitives/staking/src/lib.rs
+++ b/substrate/primitives/staking/src/lib.rs
@@ -382,15 +382,16 @@ impl<AccountId: Clone, Balance: HasCompact + AtLeast32BitUnsigned + Copy + MaxEn
 	Exposure<AccountId, Balance>
 {
 	/// Splits an `Exposure` into `PagedExposureMetadata` and multiple chunks of
-	/// `IndividualExposure` with each chunk having maximum of `page_size` elements.
+	/// `IndividualExposure` with each chunk having at least 1 element and a maximum of
+	/// `MaxExposurePageSize::get()` elements.
 	pub fn into_pages<MaxExposurePageSize>(
 		self,
-		page_size: Page,
 	) -> (PagedExposureMetadata<Balance>, Vec<ExposurePage<AccountId, Balance, MaxExposurePageSize>>)
 	where
 		MaxExposurePageSize: Get<u32>,
 	{
-		let individual_chunks = self.others.chunks(page_size as usize);
+		debug_assert!(MaxExposurePageSize::get() >= 1);
+		let individual_chunks = self.others.chunks(MaxExposurePageSize::get() as usize);
 		let mut exposure_pages: Vec<ExposurePage<AccountId, Balance, MaxExposurePageSize>> =
 			Vec::with_capacity(individual_chunks.len());