Use a more typesafe approach for managing indexed data

erasure-coding/src/lib.rs

@@ -258,7 +258,7 @@ where
 	// construct trie mapping each chunk's index to its hash.
 	{
 		let mut trie = TrieDBMut::new(&mut trie_storage, &mut root);
-		for (i, chunk) in chunks.as_ref().iter().enumerate() {
+		for (i, chunk) in chunks.iter().enumerate() {
 			(i as u32).using_encoded(|encoded_index| {
 				let chunk_hash = BlakeTwo256::hash(chunk.as_ref());
 				trie.insert(encoded_index, chunk_hash.as_ref())

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

@@ -614,7 +614,7 @@ pub(crate) mod tests {
 	use polkadot_node_subsystem::messages::{AllMessages, ApprovalVotingMessage};
 	use polkadot_node_subsystem_test_helpers::make_subsystem_context;
 	use polkadot_node_subsystem_util::database::Database;
-	use polkadot_primitives::v2::{Id as ParaId, SessionInfo, ValidatorIndex};
+	use polkadot_primitives::v2::{Id as ParaId, SessionInfo, TypeVec, ValidatorIndex};
 	pub(crate) use sp_consensus_babe::{
 		digests::{CompatibleDigestItem, PreDigest, SecondaryVRFPreDigest},
 		AllowedSlots, BabeEpochConfiguration, Epoch as BabeEpoch,
@@ -707,10 +707,10 @@ 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 _,
@@ -1169,10 +1169,13 @@ 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/availability-distribution/src/requester/session_cache.rs

@@ -197,6 +197,7 @@ impl SessionCache {
 			}
 			// Look up `AuthorityDiscoveryId`s right away:
 			let validator_groups: Vec<Vec<_>> = validator_groups
+				.to_vec()
 				.into_iter()
 				.map(|group| {
 					group

node/network/availability-recovery/src/lib.rs

@@ -846,7 +846,7 @@ async fn launch_recovery_task<Context>(
 
 	let params = RecoveryParams {
 		validator_authority_keys: session_info.discovery_keys.clone(),
-		validators: session_info.validators.clone(),
+		validators: session_info.validators.clone().to_vec(),
 		threshold: recovery_threshold(session_info.validators.len())?,
 		candidate_hash,
 		erasure_root: receipt.descriptor.erasure_root,

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

@@ -36,6 +36,12 @@ use polkadot_node_network_protocol::{
 use polkadot_node_primitives::{SignedFullStatement, Statement, UncheckedSignedFullStatement};
 use polkadot_node_subsystem_util::{self as util, rand, MIN_GOSSIP_PEERS};
 
+use polkadot_primitives::v2::{
+	AuthorityDiscoveryId, CandidateHash, CommittedCandidateReceipt, CompactStatement, Hash,
+	SignedStatement, SigningContext, TypeVec, UncheckedSignedStatement, ValidatorId,
+	ValidatorIndex, ValidatorSignature,
+};
+
 use polkadot_node_subsystem::{
 	jaeger,
 	messages::{
@@ -45,11 +51,6 @@ use polkadot_node_subsystem::{
 	overseer, ActiveLeavesUpdate, FromOrchestra, OverseerSignal, PerLeafSpan, SpawnedSubsystem,
 	SubsystemError,
 };
-use polkadot_primitives::v2::{
-	AuthorityDiscoveryId, CandidateHash, CommittedCandidateReceipt, CompactStatement, Hash,
-	SignedStatement, SigningContext, UncheckedSignedStatement, ValidatorId, ValidatorIndex,
-	ValidatorSignature,
-};
 
 use futures::{
 	channel::{mpsc, oneshot},
@@ -665,7 +666,7 @@ 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.
@@ -676,7 +677,7 @@ 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

@@ -284,17 +284,17 @@ mod tests {
 		SubsystemContext,
 	};
 	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 <[email protected]>"]
 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 = "2.1.2", 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 = []