diff --git a/polkadot/node/core/dispute-coordinator/src/real/initialized.rs b/polkadot/node/core/dispute-coordinator/src/real/initialized.rs
index bb369b28fe994c1f0310c266c812b283b2514ef8..9f9f1305a9a82d0c439dfd9c4d9e2bb8add1ce41 100644
--- a/polkadot/node/core/dispute-coordinator/src/real/initialized.rs
+++ b/polkadot/node/core/dispute-coordinator/src/real/initialized.rs
@@ -779,14 +779,21 @@ impl Initialized {
// There is one exception: A sufficiently sophisticated attacker could prevent
// us from seeing the backing votes by witholding arbitrary blocks, and hence we do
// not have a `CandidateReceipt` available.
- let mut votes = match overlay_db
+ let (mut votes, mut votes_changed) = match overlay_db
.load_candidate_votes(session, &candidate_hash)?
.map(CandidateVotes::from)
{
- Some(votes) => votes,
+ Some(votes) => (votes, false),
None =>
if let MaybeCandidateReceipt::Provides(candidate_receipt) = candidate_receipt {
- CandidateVotes { candidate_receipt, valid: Vec::new(), invalid: Vec::new() }
+ (
+ CandidateVotes {
+ candidate_receipt,
+ valid: Vec::new(),
+ invalid: Vec::new(),
+ },
+ true,
+ )
} else {
tracing::warn!(
target: LOG_TARGET,
@@ -841,22 +848,34 @@ impl Initialized {
match statement.statement().clone() {
DisputeStatement::Valid(valid_kind) => {
- self.metrics.on_valid_vote();
- insert_into_statement_vec(
+ let fresh = insert_into_statement_vec(
&mut votes.valid,
valid_kind,
*val_index,
statement.validator_signature().clone(),
);
+
+ if !fresh {
+ continue
+ }
+
+ votes_changed = true;
+ self.metrics.on_valid_vote();
},
DisputeStatement::Invalid(invalid_kind) => {
- self.metrics.on_invalid_vote();
- insert_into_statement_vec(
+ let fresh = insert_into_statement_vec(
&mut votes.invalid,
invalid_kind,
*val_index,
statement.validator_signature().clone(),
);
+
+ if !fresh {
+ continue
+ }
+
+ votes_changed = true;
+ self.metrics.on_invalid_vote();
},
}
}
@@ -871,7 +890,7 @@ impl Initialized {
// Potential spam:
if !is_confirmed {
- let mut free_spam_slots = false;
+ let mut free_spam_slots = statements.is_empty();
for (statement, index) in statements.iter() {
free_spam_slots |= statement.statement().is_backing() ||
self.spam_slots.add_unconfirmed(session, candidate_hash, *index);
@@ -988,7 +1007,10 @@ impl Initialized {
overlay_db.write_recent_disputes(recent_disputes);
}
- overlay_db.write_candidate_votes(session, candidate_hash, votes.into());
+ // Only write when votes have changed.
+ if votes_changed {
+ overlay_db.write_candidate_votes(session, candidate_hash, votes.into());
+ }
Ok(ImportStatementsResult::ValidImport)
}
@@ -1145,18 +1167,21 @@ impl MuxedMessage {
}
}
+// Returns 'true' if no other vote by that validator was already
+// present and 'false' otherwise. Same semantics as `HashSet`.
fn insert_into_statement_vec<T>(
vec: &mut Vec<(T, ValidatorIndex, ValidatorSignature)>,
tag: T,
val_index: ValidatorIndex,
val_signature: ValidatorSignature,
-) {
+) -> bool {
let pos = match vec.binary_search_by_key(&val_index, |x| x.1) {
- Ok(_) => return, // no duplicates needed.
+ Ok(_) => return false, // no duplicates needed.
Err(p) => p,
};
vec.insert(pos, (tag, val_index, val_signature));
+ true
}
#[derive(Debug, Clone)]
diff --git a/polkadot/node/core/dispute-coordinator/src/real/tests.rs b/polkadot/node/core/dispute-coordinator/src/real/tests.rs
index f3ff8a260aa5902b6bd4e62778ceac4ea4bc2405..aed361f5886faf8f13545c8c3dc8091f94adde7e 100644
--- a/polkadot/node/core/dispute-coordinator/src/real/tests.rs
+++ b/polkadot/node/core/dispute-coordinator/src/real/tests.rs
@@ -1548,3 +1548,112 @@ fn negative_issue_local_statement_only_triggers_import() {
})
});
}
+
+#[test]
+fn empty_import_still_writes_candidate_receipt() {
+ test_harness(|mut test_state, mut virtual_overseer| {
+ Box::pin(async move {
+ let session = 1;
+
+ test_state.handle_resume_sync(&mut virtual_overseer, session).await;
+
+ let candidate_receipt = make_valid_candidate_receipt();
+ let candidate_hash = candidate_receipt.hash();
+
+ test_state.activate_leaf_at_session(&mut virtual_overseer, session, 1).await;
+
+ let (tx, rx) = oneshot::channel();
+ virtual_overseer
+ .send(FromOverseer::Communication {
+ msg: DisputeCoordinatorMessage::ImportStatements {
+ candidate_hash,
+ candidate_receipt: candidate_receipt.clone(),
+ session,
+ statements: Vec::new(),
+ pending_confirmation: tx,
+ },
+ })
+ .await;
+
+ rx.await.unwrap();
+
+ let backend = DbBackend::new(test_state.db.clone(), test_state.config.column_config());
+
+ let votes = backend.load_candidate_votes(session, &candidate_hash).unwrap().unwrap();
+ assert_eq!(votes.invalid.len(), 0);
+ assert_eq!(votes.valid.len(), 0);
+ assert_eq!(votes.candidate_receipt, candidate_receipt);
+
+ virtual_overseer.send(FromOverseer::Signal(OverseerSignal::Conclude)).await;
+ assert!(virtual_overseer.try_recv().await.is_none());
+
+ test_state
+ })
+ });
+}
+
+#[test]
+fn redundant_votes_ignored() {
+ test_harness(|mut test_state, mut virtual_overseer| {
+ Box::pin(async move {
+ let session = 1;
+
+ test_state.handle_resume_sync(&mut virtual_overseer, session).await;
+
+ let candidate_receipt = make_valid_candidate_receipt();
+ let candidate_hash = candidate_receipt.hash();
+
+ test_state.activate_leaf_at_session(&mut virtual_overseer, session, 1).await;
+
+ let valid_vote =
+ test_state.issue_statement_with_index(1, candidate_hash, session, true).await;
+
+ let valid_vote_2 =
+ test_state.issue_statement_with_index(1, candidate_hash, session, true).await;
+
+ assert!(valid_vote.validator_signature() != valid_vote_2.validator_signature());
+
+ let (tx, rx) = oneshot::channel();
+ virtual_overseer
+ .send(FromOverseer::Communication {
+ msg: DisputeCoordinatorMessage::ImportStatements {
+ candidate_hash,
+ candidate_receipt: candidate_receipt.clone(),
+ session,
+ statements: vec![(valid_vote.clone(), ValidatorIndex(1))],
+ pending_confirmation: tx,
+ },
+ })
+ .await;
+
+ rx.await.unwrap();
+
+ let (tx, rx) = oneshot::channel();
+ virtual_overseer
+ .send(FromOverseer::Communication {
+ msg: DisputeCoordinatorMessage::ImportStatements {
+ candidate_hash,
+ candidate_receipt: candidate_receipt.clone(),
+ session,
+ statements: vec![(valid_vote_2, ValidatorIndex(1))],
+ pending_confirmation: tx,
+ },
+ })
+ .await;
+
+ rx.await.unwrap();
+
+ let backend = DbBackend::new(test_state.db.clone(), test_state.config.column_config());
+
+ let votes = backend.load_candidate_votes(session, &candidate_hash).unwrap().unwrap();
+ assert_eq!(votes.invalid.len(), 0);
+ assert_eq!(votes.valid.len(), 1);
+ assert_eq!(&votes.valid[0].2, valid_vote.validator_signature());
+
+ virtual_overseer.send(FromOverseer::Signal(OverseerSignal::Conclude)).await;
+ assert!(virtual_overseer.try_recv().await.is_none());
+
+ test_state
+ })
+ });
+}