Disabled validators runtime API (#1257)

Exposes disabled validators list via a runtime API.

---------

Co-authored-by: ordian <noreply@reusable.software>
Co-authored-by: ordian <write@reusable.software>

polkadot/runtime/parachains/src/runtime_api_impl/vstaging.rs

@@ -15,3 +15,30 @@
 // along with Polkadot.  If not, see <http://www.gnu.org/licenses/>.
 
 //! Put implementations of functions from staging APIs here.
+
+use crate::shared;
+use primitives::ValidatorIndex;
+use sp_std::{collections::btree_map::BTreeMap, prelude::Vec};
+
+/// Implementation for `DisabledValidators`
+// CAVEAT: this should only be called on the node side
+// as it might produce incorrect results on session boundaries
+pub fn disabled_validators<T>() -> Vec<ValidatorIndex>
+where
+	T: pallet_session::Config + shared::Config,
+{
+	let shuffled_indices = <shared::Pallet<T>>::active_validator_indices();
+	// mapping from raw validator index to `ValidatorIndex`
+	// this computation is the same within a session, but should be cheap
+	let reverse_index = shuffled_indices
+		.iter()
+		.enumerate()
+		.map(|(i, v)| (v.0, ValidatorIndex(i as u32)))
+		.collect::<BTreeMap<u32, ValidatorIndex>>();
+
+	// we might have disabled validators who are not parachain validators
+	<pallet_session::Pallet<T>>::disabled_validators()
+		.iter()
+		.filter_map(|v| reverse_index.get(v).cloned())
+		.collect()
+}

polkadot/runtime/rococo/src/lib.rs

@@ -49,7 +49,9 @@ use runtime_parachains::{
 	inclusion::{AggregateMessageOrigin, UmpQueueId},
 	initializer as parachains_initializer, origin as parachains_origin, paras as parachains_paras,
 	paras_inherent as parachains_paras_inherent,
-	runtime_api_impl::v7 as parachains_runtime_api_impl,
+	runtime_api_impl::{
+		v7 as parachains_runtime_api_impl, vstaging as parachains_staging_runtime_api_impl,
+	},
 	scheduler as parachains_scheduler, session_info as parachains_session_info,
 	shared as parachains_shared,
 };
@@ -1585,7 +1587,7 @@ sp_api::impl_runtime_apis! {
 		}
 	}
 
-	#[api_version(7)]
+	#[api_version(8)]
 	impl primitives::runtime_api::ParachainHost<Block, Hash, BlockNumber> for Runtime {
 		fn validators() -> Vec<ValidatorId> {
 			parachains_runtime_api_impl::validators::<Runtime>()
@@ -1728,6 +1730,11 @@ sp_api::impl_runtime_apis! {
 		fn async_backing_params() -> primitives::AsyncBackingParams {
 			parachains_runtime_api_impl::async_backing_params::<Runtime>()
 		}
+
+		fn disabled_validators() -> Vec<ValidatorIndex> {
+			parachains_staging_runtime_api_impl::disabled_validators::<Runtime>()
+		}
+
 	}
 
 	#[api_version(3)]

polkadot/runtime/westend/src/lib.rs

@@ -70,7 +70,9 @@ use runtime_parachains::{
 	inclusion::{AggregateMessageOrigin, UmpQueueId},
 	initializer as parachains_initializer, origin as parachains_origin, paras as parachains_paras,
 	paras_inherent as parachains_paras_inherent, reward_points as parachains_reward_points,
-	runtime_api_impl::v7 as parachains_runtime_api_impl,
+	runtime_api_impl::{
+		v7 as parachains_runtime_api_impl, vstaging as parachains_staging_runtime_api_impl,
+	},
 	scheduler as parachains_scheduler, session_info as parachains_session_info,
 	shared as parachains_shared,
 };
@@ -1695,7 +1697,7 @@ sp_api::impl_runtime_apis! {
 		}
 	}
 
-	#[api_version(7)]
+	#[api_version(8)]
 	impl primitives::runtime_api::ParachainHost<Block, Hash, BlockNumber> for Runtime {
 		fn validators() -> Vec<ValidatorId> {
 			parachains_runtime_api_impl::validators::<Runtime>()
@@ -1838,6 +1840,10 @@ sp_api::impl_runtime_apis! {
 		fn async_backing_params() -> primitives::AsyncBackingParams {
 			parachains_runtime_api_impl::async_backing_params::<Runtime>()
 		}
+
+		fn disabled_validators() -> Vec<ValidatorIndex> {
+			parachains_staging_runtime_api_impl::disabled_validators::<Runtime>()
+		}
 	}
 
 	impl beefy_primitives::BeefyApi<Block, BeefyId> for Runtime {