Use a more typesafe approach for managing indexed data

node/core/approval-voting/src/criteria.rs

@@ -21,7 +21,8 @@ use polkadot_node_primitives::approval::{
 	self as approval_types, AssignmentCert, AssignmentCertKind, DelayTranche, RelayVRFStory,
 };
 use polkadot_primitives::v2::{
-	AssignmentId, AssignmentPair, CandidateHash, CoreIndex, GroupIndex, SessionInfo, ValidatorIndex,
+	AssignmentId, AssignmentPair, CandidateHash, CoreIndex, GroupIndex, SessionInfo, TypeVec,
+	ValidatorIndex,
 };
 use sc_keystore::LocalKeystore;
 use sp_application_crypto::ByteArray;
@@ -138,7 +139,7 @@ pub(crate) struct Config {
 	/// The assignment public keys for validators.
 	assignment_keys: Vec<AssignmentId>,
 	/// The groups of validators assigned to each core.
-	validator_groups: Vec<Vec<ValidatorIndex>>,
+	validator_groups: TypeVec<GroupIndex, Vec<ValidatorIndex>>,
 	/// The number of availability cores used by the protocol during this session.
 	n_cores: u32,
 	/// The zeroth delay tranche width.
@@ -631,10 +632,10 @@ mod tests {
 					Sr25519Keyring::Bob,
 					Sr25519Keyring::Charlie,
 				]),
-				validator_groups: vec![
+				validator_groups: TypeVec::from(vec![
 					vec![ValidatorIndex(0)],
 					vec![ValidatorIndex(1), ValidatorIndex(2)],
-				],
+				]),
 				n_cores: 2,
 				zeroth_delay_tranche_width: 10,
 				relay_vrf_modulo_samples: 3,
@@ -666,10 +667,10 @@ mod tests {
 					Sr25519Keyring::Bob,
 					Sr25519Keyring::Charlie,
 				]),
-				validator_groups: vec![
+				validator_groups: TypeVec::from(vec![
 					vec![ValidatorIndex(0)],
 					vec![ValidatorIndex(1), ValidatorIndex(2)],
-				],
+				]),
 				n_cores: 2,
 				zeroth_delay_tranche_width: 10,
 				relay_vrf_modulo_samples: 3,
@@ -696,7 +697,7 @@ mod tests {
 					Sr25519Keyring::Bob,
 					Sr25519Keyring::Charlie,
 				]),
-				validator_groups: vec![],
+				validator_groups: TypeVec::from(vec![]),
 				n_cores: 0,
 				zeroth_delay_tranche_width: 10,
 				relay_vrf_modulo_samples: 3,
@@ -733,7 +734,7 @@ mod tests {
 				&[Sr25519Keyring::Alice],
 				n_validators - 1,
 			),
-			validator_groups: basic_groups(n_validators, n_cores),
+			validator_groups: TypeVec::from(basic_groups(n_validators, n_cores)),
 			n_cores: n_cores as u32,
 			zeroth_delay_tranche_width: 10,
 			relay_vrf_modulo_samples: 3,

node/core/approval-voting/src/import.rs

@@ -46,7 +46,7 @@ use polkadot_node_subsystem_util::{
 };
 use polkadot_primitives::v2::{
 	BlockNumber, CandidateEvent, CandidateHash, CandidateReceipt, ConsensusLog, CoreIndex,
-	GroupIndex, Hash, Header, SessionIndex,
+	GroupIndex, Hash, Header, SessionIndex, TypeVec,
 };
 use sc_keystore::LocalKeystore;
 use sp_consensus_slots::Slot;
@@ -612,7 +612,7 @@ pub(crate) mod tests {
 	use polkadot_node_subsystem::messages::AllMessages;
 	use polkadot_node_subsystem_test_helpers::make_subsystem_context;
 	use polkadot_node_subsystem_util::database::Database;
-	use polkadot_primitives::v2::{SessionInfo, ValidatorIndex};
+	use polkadot_primitives::v2::{SessionInfo, TypeVec, ValidatorIndex};
 	pub(crate) use sp_consensus_babe::{
 		digests::{CompatibleDigestItem, PreDigest, SecondaryVRFPreDigest},
 		AllowedSlots, BabeEpochConfiguration, Epoch as BabeEpoch,
@@ -705,10 +705,10 @@ pub(crate) mod tests {
 
 	fn dummy_session_info(index: SessionIndex) -> SessionInfo {
 		SessionInfo {
-			validators: Vec::new(),
+			validators: TypeVec::new(),
 			discovery_keys: Vec::new(),
 			assignment_keys: Vec::new(),
-			validator_groups: Vec::new(),
+			validator_groups: TypeVec::new(),
 			n_cores: index as _,
 			zeroth_delay_tranche_width: index as _,
 			relay_vrf_modulo_samples: index as _,
@@ -1163,10 +1163,13 @@ pub(crate) mod tests {
 		let session = 5;
 		let irrelevant = 666;
 		let session_info = SessionInfo {
-			validators: vec![Sr25519Keyring::Alice.public().into(); 6],
+			validators: TypeVec::from(vec![Sr25519Keyring::Alice.public().into(); 6]),
 			discovery_keys: Vec::new(),
 			assignment_keys: Vec::new(),
-			validator_groups: vec![vec![ValidatorIndex(0); 5], vec![ValidatorIndex(0); 2]],
+			validator_groups: TypeVec::from(vec![
+				vec![ValidatorIndex(0); 5],
+				vec![ValidatorIndex(0); 2],
+			]),
 			n_cores: 6,
 			needed_approvals: 2,
 			zeroth_delay_tranche_width: irrelevant,

node/network/statement-distribution/src/lib.rs

@@ -37,8 +37,8 @@ use polkadot_node_subsystem_util::{self as util, rand, MIN_GOSSIP_PEERS};
 
 use polkadot_primitives::v2::{
 	AuthorityDiscoveryId, CandidateHash, CommittedCandidateReceipt, CompactStatement, Hash,
-	SignedStatement, SigningContext, UncheckedSignedStatement, ValidatorId, ValidatorIndex,
-	ValidatorSignature,
+	SignedStatement, SigningContext, TypeVec, UncheckedSignedStatement, ValidatorId,
+	ValidatorIndex, ValidatorSignature,
 };
 use polkadot_subsystem::{
 	jaeger,
@@ -668,7 +668,7 @@ struct ActiveHeadData {
 	/// Large statements we are waiting for with associated meta data.
 	waiting_large_statements: HashMap<CandidateHash, LargeStatementStatus>,
 	/// The parachain validators at the head's child session index.
-	validators: Vec<ValidatorId>,
+	validators: TypeVec<ValidatorIndex, ValidatorId>,
 	/// The current session index of this fork.
 	session_index: sp_staking::SessionIndex,
 	/// How many `Seconded` statements we've seen per validator.
@@ -679,7 +679,7 @@ struct ActiveHeadData {
 
 impl ActiveHeadData {
 	fn new(
-		validators: Vec<ValidatorId>,
+		validators: TypeVec<ValidatorIndex, ValidatorId>,
 		session_index: sp_staking::SessionIndex,
 		span: PerLeafSpan,
 	) -> Self {

node/subsystem-util/src/rolling_session_window.rs

@@ -276,17 +276,17 @@ mod tests {
 	use assert_matches::assert_matches;
 	use polkadot_node_subsystem::messages::{AllMessages, AvailabilityRecoveryMessage};
 	use polkadot_node_subsystem_test_helpers::make_subsystem_context;
-	use polkadot_primitives::v2::Header;
+	use polkadot_primitives::v2::{Header, TypeVec};
 	use sp_core::testing::TaskExecutor;
 
 	pub const TEST_WINDOW_SIZE: SessionWindowSize = new_session_window_size!(6);
 
 	fn dummy_session_info(index: SessionIndex) -> SessionInfo {
 		SessionInfo {
-			validators: Vec::new(),
+			validators: TypeVec::new(),
 			discovery_keys: Vec::new(),
 			assignment_keys: Vec::new(),
-			validator_groups: Vec::new(),
+			validator_groups: TypeVec::new(),
 			n_cores: index as _,
 			zeroth_delay_tranche_width: index as _,
 			relay_vrf_modulo_samples: index as _,

primitives/Cargo.toml

@@ -5,6 +5,7 @@ authors = ["Parity Technologies <admin@parity.io>"]
 edition = "2021"
 
 [dependencies]
+typed-index-collections = { version = "3.0.3", default-features = false, features = ["alloc","serde","serde-alloc"] }
 serde = { version = "1.0.137", optional = true, features = ["derive"] }
 scale-info = { version = "2.1.1", default-features = false, features = ["bit-vec", "derive"] }
 parity-scale-codec = { version = "3.1.2", default-features = false, features = ["bit-vec", "derive"] }
@@ -54,5 +55,6 @@ std = [
 	"polkadot-core-primitives/std",
 	"bitvec/std",
 	"frame-system/std",
+	"typed-index-collections/std"
 ]
 runtime-benchmarks = []

primitives/src/v2/mod.rs

@@ -17,9 +17,11 @@
 //! `V1` Primitives.
 
 use bitvec::vec::BitVec;
-use parity_scale_codec::{Decode, Encode};
-use scale_info::TypeInfo;
+use parity_scale_codec::{Decode, Encode, WrapperTypeDecode, WrapperTypeEncode};
+use scale_info::{Type, TypeInfo};
 use sp_std::prelude::*;
+use std::ops::{Deref, DerefMut};
+use typed_index_collections::TiVec;
 
 use application_crypto::KeyTypeId;
 use inherents::InherentIdentifier;
@@ -53,9 +55,11 @@ pub use sp_staking::SessionIndex;
 
 /// Signed data.
 mod signed;
+
 pub use signed::{EncodeAs, Signed, UncheckedSigned};
 
 mod metrics;
+
 pub use metrics::{
 	metric_definitions, RuntimeMetricLabel, RuntimeMetricLabelValue, RuntimeMetricLabelValues,
 	RuntimeMetricLabels, RuntimeMetricOp, RuntimeMetricUpdate,
@@ -135,6 +139,20 @@ impl From<u32> for ValidatorIndex {
 	}
 }
 
+impl From<ValidatorIndex> for usize {
+	fn from(n: ValidatorIndex) -> Self {
+		n.0 as usize
+	}
+}
+
+impl From<usize> for ValidatorIndex {
+	fn from(n: usize) -> Self {
+		// can't panic, so need to truncate
+		let n = n.try_into().unwrap_or(u32::MAX);
+		ValidatorIndex(n)
+	}
+}
+
 application_crypto::with_pair! {
 	/// A Parachain validator keypair.
 	pub type ValidatorPair = validator_app::Pair;
@@ -790,6 +808,14 @@ impl From<u32> for GroupIndex {
 	}
 }
 
+impl From<usize> for GroupIndex {
+	fn from(n: usize) -> Self {
+		// can't panic, so need to truncate
+		let n = n.try_into().unwrap_or(u32::MAX);
+		GroupIndex(n)
+	}
+}
+
 /// A claim on authoring the next block for a given parathread.
 #[derive(Clone, Encode, Decode, TypeInfo, RuntimeDebug)]
 #[cfg_attr(feature = "std", derive(PartialEq))]
@@ -1394,9 +1420,11 @@ pub type CheckedMultiDisputeStatementSet = Vec<CheckedDisputeStatementSet>;
 #[derive(Encode, Decode, Clone, RuntimeDebug, PartialEq, TypeInfo)]
 pub struct DisputeState<N = BlockNumber> {
 	/// A bitfield indicating all validators for the candidate.
-	pub validators_for: BitVec<u8, bitvec::order::Lsb0>, // one bit per validator.
+	pub validators_for: BitVec<u8, bitvec::order::Lsb0>,
+	// one bit per validator.
 	/// A bitfield indicating all validators against the candidate.
-	pub validators_against: BitVec<u8, bitvec::order::Lsb0>, // one bit per validator.
+	pub validators_against: BitVec<u8, bitvec::order::Lsb0>,
+	// one bit per validator.
 	/// The block number at which the dispute started on-chain.
 	pub start: N,
 	/// The block number at which the dispute concluded on-chain.
@@ -1582,6 +1610,64 @@ pub fn supermajority_threshold(n: usize) -> usize {
 	n - byzantine_threshold(n)
 }
 
+#[derive(Clone, RuntimeDebug)]
+#[cfg_attr(feature = "std", derive(PartialEq))]
+pub struct TypeVec<K: From<usize>, V: Clone>(TiVec<K, V>);
+
+impl<K: From<usize>, V: Clone> TypeVec<K, V> {
+	pub fn new() -> Self {
+		TypeVec::<K, V> { 0: TiVec::<K, V>::new() }
+	}
+}
+
+impl<K: From<usize>, V: Clone> From<Vec<V>> for TypeVec<K, V> {
+	fn from(vec: Vec<V>) -> Self {
+		let mut type_vec: TypeVec<K, V> = TypeVec::new();
+		for value in vec.iter() {
+			type_vec.0.push(value.clone())
+		}
+		type_vec
+	}
+}
+
+#[cfg(feature = "std")]
+impl<K: From<usize>, V: Clone> MallocSizeOf for TypeVec<K, V> {
+	fn size_of(&self, _ops: &mut MallocSizeOfOps) -> usize {
+		0
+	}
+	fn constant_size() -> Option<usize> {
+		Some(0)
+	}
+}
+
+impl<K: From<usize>, V: Clone> Deref for TypeVec<K, V> {
+	type Target = Vec<V>;
+
+	fn deref(&self) -> &Self::Target {
+		&self.0.raw
+	}
+}
+
+impl<K: From<usize>, V: Clone> DerefMut for TypeVec<K, V> {
+	fn deref_mut(&mut self) -> &mut Self::Target {
+		&mut self.0.raw
+	}
+}
+
+impl<K: From<usize>, V: Clone> WrapperTypeEncode for TypeVec<K, V> {}
+
+impl<K: From<usize>, V: Clone> WrapperTypeDecode for TypeVec<K, V> {
+	type Wrapped = Vec<V>;
+}
+
+impl<K: From<usize>, V: Clone> TypeInfo for TypeVec<K, V> {
+	type Identity = ();
+
+	fn type_info() -> Type {
+		todo!()
+	}
+}
+
 /// Information about validator sets of a session.
 #[derive(Clone, Encode, Decode, RuntimeDebug, TypeInfo)]
 #[cfg_attr(feature = "std", derive(PartialEq, MallocSizeOf))]
@@ -1603,7 +1689,7 @@ pub struct SessionInfo {
 	/// [`max_validators`](https://github.com/paritytech/polkadot/blob/a52dca2be7840b23c19c153cf7e110b1e3e475f8/runtime/parachains/src/configuration.rs#L148).
 	///
 	/// `SessionInfo::validators` will be limited to to `max_validators` when set.
-	pub validators: Vec<ValidatorId>,
+	pub validators: TypeVec<ValidatorIndex, ValidatorId>,
 	/// Validators' authority discovery keys for the session in canonical ordering.
 	///
 	/// NOTE: The first `validators.len()` entries will match the corresponding validators in
@@ -1620,13 +1706,13 @@ pub struct SessionInfo {
 	///
 	/// Therefore:
 	/// ```ignore
-	///		assignment_keys.len() == validators.len() && validators.len() <= discovery_keys.len()
-	///	```
+	///    	assignment_keys.len() == validators.len() && validators.len() <= discovery_keys.len()
+	///    ```
 	pub assignment_keys: Vec<AssignmentId>,
 	/// Validators in shuffled ordering - these are the validator groups as produced
 	/// by the `Scheduler` module for the session and are typically referred to by
 	/// `GroupIndex`.
-	pub validator_groups: Vec<Vec<ValidatorIndex>>,
+	pub validator_groups: TypeVec<GroupIndex, Vec<ValidatorIndex>>,
 	/// The number of availability cores used by the protocol during this session.
 	pub n_cores: u32,
 	/// The zeroth delay tranche width.
@@ -1679,7 +1765,7 @@ pub struct OldV1SessionInfo {
 	/// [`max_validators`](https://github.com/paritytech/polkadot/blob/a52dca2be7840b23c19c153cf7e110b1e3e475f8/runtime/parachains/src/configuration.rs#L148).
 	///
 	/// `SessionInfo::validators` will be limited to to `max_validators` when set.
-	pub validators: Vec<ValidatorId>,
+	pub validators: TypeVec<ValidatorIndex, ValidatorId>,
 	/// Validators' authority discovery keys for the session in canonical ordering.
 	///
 	/// NOTE: The first `validators.len()` entries will match the corresponding validators in
@@ -1696,13 +1782,13 @@ pub struct OldV1SessionInfo {
 	///
 	/// Therefore:
 	/// ```ignore
-	///		assignment_keys.len() == validators.len() && validators.len() <= discovery_keys.len()
-	///	```
+	///    	assignment_keys.len() == validators.len() && validators.len() <= discovery_keys.len()
+	///    ```
 	pub assignment_keys: Vec<AssignmentId>,
 	/// Validators in shuffled ordering - these are the validator groups as produced
 	/// by the `Scheduler` module for the session and are typically referred to by
 	/// `GroupIndex`.
-	pub validator_groups: Vec<Vec<ValidatorIndex>>,
+	pub validator_groups: TypeVec<GroupIndex, Vec<ValidatorIndex>>,
 	/// The number of availability cores used by the protocol during this session.
 	pub n_cores: u32,
 	/// The zeroth delay tranche width.