remove deprecated remove_prefix to clear era_info (#13460)

* remove deprecated remove_prefix to clear era_info

* add debug assertions to check that the returned cursor is None

* add a variable to hold the cursor

* ".git/.scripts/commands/fmt/fmt.sh"

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Co-authored-by: command-bot <>

frame/staking/src/pallet/impls.rs

@@ -669,12 +669,12 @@ impl<T: Config> Pallet<T> {
 
 	/// Clear all era information for given era.
 	pub(crate) fn clear_era_information(era_index: EraIndex) {
-		#[allow(deprecated)]
-		<ErasStakers<T>>::remove_prefix(era_index, None);
-		#[allow(deprecated)]
-		<ErasStakersClipped<T>>::remove_prefix(era_index, None);
-		#[allow(deprecated)]
-		<ErasValidatorPrefs<T>>::remove_prefix(era_index, None);
+		let mut cursor = <ErasStakers<T>>::clear_prefix(era_index, u32::MAX, None);
+		debug_assert!(cursor.maybe_cursor.is_none());
+		cursor = <ErasStakersClipped<T>>::clear_prefix(era_index, u32::MAX, None);
+		debug_assert!(cursor.maybe_cursor.is_none());
+		cursor = <ErasValidatorPrefs<T>>::clear_prefix(era_index, u32::MAX, None);
+		debug_assert!(cursor.maybe_cursor.is_none());
 		<ErasValidatorReward<T>>::remove(era_index);
 		<ErasRewardPoints<T>>::remove(era_index);
 		<ErasTotalStake<T>>::remove(era_index);