Issue 6274: keeping all backing votes in provisioner vote set (parity…

…tech#6494)

* Fixing filter to keep all backing votes

* Comment and implementers guide edit

* Formatting

* Using fallthrough

* Fmt

node/core/provisioner/src/disputes/prioritized_selection/mod.rs

@@ -28,7 +28,7 @@ use polkadot_node_subsystem::{
 };
 use polkadot_primitives::v2::{
 	supermajority_threshold, CandidateHash, DisputeState, DisputeStatement, DisputeStatementSet,
-	Hash, MultiDisputeStatementSet, SessionIndex, ValidatorIndex,
+	Hash, MultiDisputeStatementSet, SessionIndex, ValidDisputeStatementKind, ValidatorIndex,
 };
 use std::{
 	collections::{BTreeMap, HashMap},
@@ -364,10 +364,20 @@ fn is_vote_worth_to_keep(
 	dispute_statement: DisputeStatement,
 	onchain_state: &DisputeState,
 ) -> bool {
-	let offchain_vote = match dispute_statement {
-		DisputeStatement::Valid(_) => true,
-		DisputeStatement::Invalid(_) => false,
+	let (offchain_vote, valid_kind) = match dispute_statement {
+		DisputeStatement::Valid(kind) => (true, Some(kind)),
+		DisputeStatement::Invalid(_) => (false, None),
 	};
+	// We want to keep all backing votes. This maximizes the number of backers
+	// punished when misbehaving.
+	if let Some(kind) = valid_kind {
+		match kind {
+			ValidDisputeStatementKind::BackingValid(_) |
+			ValidDisputeStatementKind::BackingSeconded(_) => return true,
+			_ => (),
+		}
+	}
+
 	let in_validators_for = onchain_state
 		.validators_for
 		.get(validator_index.0 as usize)

roadmap/implementers-guide/src/node/utility/provisioner.md

@@ -73,7 +73,7 @@ The end result of this process is a vector of `BackedCandidate`s, sorted in orde
 
 This is the point at which the block author provides further votes to active disputes or initiates new disputes in the runtime state.
 
-The block-authoring logic of the runtime has an extra step between handling the inherent-data and producing the actual inherent call, which we assume performs the work of filtering out disputes which are not relevant to the on-chain state.
+The block-authoring logic of the runtime has an extra step between handling the inherent-data and producing the actual inherent call, which we assume performs the work of filtering out disputes which are not relevant to the on-chain state. Backing votes are always kept in the dispute statement set. This ensures we punish the maximum number of misbehaving backers.
 
 To select disputes: