feat: implement should_apply_proposer_boost for gloas

packages/beacon-node/src/chain/forkChoice/index.ts

@@ -134,6 +134,8 @@ export function initializeForkChoiceFromFinalizedState(
         stateRoot: toRootHex(blockHeader.stateRoot),
         blockRoot: toRootHex(checkpoint.root),
         timeliness: true, // Optimistically assume is timely
+        ptcTimeliness: true, // Spec: block_timeliness for anchor = [True, True]
+        proposerIndex: blockHeader.proposerIndex,
 
         justifiedEpoch: justifiedCheckpoint.epoch,
         justifiedRoot: toRootHex(justifiedCheckpoint.root),
@@ -230,6 +232,8 @@ export function initializeForkChoiceFromUnfinalizedState(
     blockRoot: headRoot,
     targetRoot: headRoot,
     timeliness: true, // Optimistically assume is timely
+    ptcTimeliness: true, // Spec: block_timeliness for anchor = [True, True]
+    proposerIndex: blockHeader.proposerIndex,
 
     justifiedEpoch: justifiedCheckpoint.epoch,
     justifiedRoot: toRootHex(justifiedCheckpoint.root),

packages/beacon-node/test/perf/chain/opPools/aggregatedAttestationPool.test.ts

@@ -67,6 +67,8 @@ describe.skip(`getAttestationsForBlock vc=${vc}`, () => {
           executionStatus: ExecutionStatus.PreMerge,
 
           timeliness: false,
+          ptcTimeliness: false,
+          proposerIndex: 0,
           dataAvailabilityStatus: DataAvailabilityStatus.PreData,
 
           parentBlockHash: null,
@@ -95,6 +97,8 @@ describe.skip(`getAttestationsForBlock vc=${vc}`, () => {
             executionPayloadBlockHash: null,
             executionStatus: ExecutionStatus.PreMerge,
             timeliness: false,
+            ptcTimeliness: false,
+            proposerIndex: 0,
             dataAvailabilityStatus: DataAvailabilityStatus.PreData,
 
             parentBlockHash: null,

packages/beacon-node/test/spec/utils/specTestIterator.ts

@@ -88,11 +88,6 @@ export const defaultSkipOpts: SkipOpts = {
     // handling is not yet implemented in Lodestar.
     /^gloas\/fork_choice\/on_payload_attestation_message\/.*$/,
     /^heze\/fork_choice\/on_payload_attestation_message\/.*$/,
-    // TODO-GLOAS: re-enable after the gloas should_apply_proposer_boost rule is implemented.
-    // New test suite added by consensus-specs #5441; Lodestar still applies
-    // the pre-gloas proposer boost, so the head weight differs by the boost amount.
-    /^gloas\/fork_choice\/should_apply_proposer_boost\/.*$/,
-    /^heze\/fork_choice\/should_apply_proposer_boost\/.*$/,
     // TODO GLOAS: enable this after gloas fork choice is ready
     /^gloas\/fork_choice_compliance\/.*/,
     /^heze\/fork_choice_compliance\/.*/,

packages/beacon-node/test/unit/chain/seenCache/seenPayloadEnvelopeInput.test.ts

@@ -106,6 +106,8 @@ describe("SeenPayloadEnvelopeInput", () => {
       unrealizedFinalizedEpoch: 0,
       unrealizedFinalizedRoot: blockRoot,
       timeliness: false,
+      ptcTimeliness: false,
+      proposerIndex: 0,
       executionPayloadBlockHash: null,
       executionStatus: ExecutionStatus.PreMerge,
       dataAvailabilityStatus: DataAvailabilityStatus.PreData,

packages/beacon-node/test/utils/state.ts

@@ -169,6 +169,8 @@ export const zeroProtoBlock: ProtoBlock = {
   unrealizedFinalizedRoot: ZERO_HASH_HEX,
 
   timeliness: false,
+  ptcTimeliness: false,
+  proposerIndex: 0,
 
   ...{executionPayloadBlockHash: null, executionStatus: ExecutionStatus.PreMerge},
   dataAvailabilityStatus: DataAvailabilityStatus.PreData,

packages/beacon-node/test/utils/typeGenerator.ts

@@ -40,6 +40,8 @@ export function generateProtoBlock(overrides: Partial<ProtoBlock> = {}): ProtoBl
     unrealizedFinalizedRoot: ZERO_HASH_HEX,
 
     timeliness: false,
+    ptcTimeliness: false,
+    proposerIndex: 0,
     payloadStatus: PayloadStatus.FULL,
     parentBlockHash: null,
 

packages/beacon-node/test/utils/validationData/attestation.ts

@@ -76,6 +76,8 @@ export function getAttestationValidData(opts: AttestationValidDataOpts): {
     unrealizedFinalizedRoot: ZERO_HASH_HEX,
 
     timeliness: false,
+    ptcTimeliness: false,
+    proposerIndex: 0,
 
     executionPayloadBlockHash: null,
     executionStatus: ExecutionStatus.PreMerge,

packages/fork-choice/src/forkChoice/forkChoice.ts

@@ -591,32 +591,48 @@ export class ForkChoice implements IForkChoice {
     computeDeltasMetrics?.newVoteValidators.set(newVoteValidators);
 
     this.balances = newBalances;
-    /**
-     * The structure in line with deltas to propagate boost up the branch
-     * starting from the proposerIndex
-     */
-    let proposerBoost: {root: RootHex; score: bigint} | null = null;
-    if (this.opts?.proposerBoost && this.proposerBoostRoot) {
-      const proposerBoostScore =
-        this.justifiedProposerBoostScore ??
-        getCommitteeFraction(this.fcStore.justified.totalBalance, {
-          slotsPerEpoch: SLOTS_PER_EPOCH,
-          committeePercent: this.config.PROPOSER_SCORE_BOOST,
-        });
-      proposerBoost = {root: this.proposerBoostRoot, score: proposerBoostScore};
-      this.justifiedProposerBoostScore = proposerBoostScore;
-    }
 
     const currentSlot = this.fcStore.currentSlot;
-    this.protoArray.applyScoreChanges({
-      attestationDeltas,
-      proposerBoost,
+    const checkpoints = {
       justifiedEpoch: this.fcStore.justified.checkpoint.epoch,
       justifiedRoot: this.fcStore.justified.checkpoint.rootHex,
       finalizedEpoch: this.fcStore.finalizedCheckpoint.epoch,
       finalizedRoot: this.fcStore.finalizedCheckpoint.rootHex,
       currentSlot,
-    });
+    };
+
+    const boostedBlock =
+      this.opts?.proposerBoost && this.proposerBoostRoot ? this.getBlockHexDefaultStatus(this.proposerBoostRoot) : null;
+
+    if (boostedBlock && isGloasBlock(boostedBlock)) {
+      // should_apply_proposer_boost judges the parent against the attestations known to the store,
+      // via is_head_weak (which also assumes equivocators' votes were already discounted before
+      // their balance is added back). Apply the attestation deltas first so the decision reads
+      // post-delta scores, then apply the boost in a second pass.
+      // TODO GLOAS: applyScoreChanges() updates weights and best child/descendant in one call;
+      // splitting them would let the two passes update weights and recompute best child/descendant
+      // once at the end.
+      // https://github.com/ethereum/consensus-specs/blob/v1.7.0-alpha.14/specs/gloas/fork-choice.md#new-should_apply_proposer_boost
+      this.protoArray.applyScoreChanges({attestationDeltas, proposerBoost: null, ...checkpoints});
+      const proposerBoost = this.shouldApplyProposerBoost() ? this.getProposerBoost() : null;
+      // The first pass already rolled back the previous boost and left a coherent tree, so a
+      // withheld boost needs no second pass
+      if (proposerBoost !== null) {
+        this.protoArray.applyScoreChanges({
+          attestationDeltas: new Array<number>(this.protoArray.nodes.length).fill(0),
+          proposerBoost,
+          ...checkpoints,
+        });
+      }
+    } else {
+      // Pre-gloas the boost is unconditional, so attestation deltas and boost deltas can propagate
+      // up the branch in a single pass
+      this.protoArray.applyScoreChanges({
+        attestationDeltas,
+        proposerBoost: boostedBlock ? this.getProposerBoost() : null,
+        ...checkpoints,
+      });
+    }
 
     // findHead returns the ProtoNode representing the head
     const head = this.protoArray.findHead(this.fcStore.justified.checkpoint.rootHex, currentSlot);
@@ -826,6 +842,8 @@ export class ForkChoice implements IForkChoice {
       targetRoot: toRootHex(targetRoot),
       stateRoot: toRootHex(block.stateRoot),
       timeliness: isTimely,
+      ptcTimeliness: this.isBlockPtcTimely(block, blockDelaySec),
+      proposerIndex: block.proposerIndex,
 
       justifiedEpoch: stateJustifiedEpoch,
       justifiedRoot: toRootHex(state.currentJustifiedCheckpoint.root),
@@ -1602,7 +1620,8 @@ export class ForkChoice implements IForkChoice {
     // Only ever called on a block already in fork choice, so a miss is a broken invariant.
     const node = this.protoArray.getNodeDefaultStatus(blockRoot);
     if (node === undefined) {
-      // this is called for head so we should always have this in forkchoice, otherwise we have a serious error
+      // this is called for head or the boosted block's parent, both of which should always be
+      // in forkchoice, otherwise we have a serious error
       throw new ForkChoiceError({code: ForkChoiceErrorCode.MISSING_PROTO_ARRAY_BLOCK, root: blockRoot});
     }
 
@@ -1622,7 +1641,7 @@ export class ForkChoice implements IForkChoice {
     // always 0. Return before fetching the state and walking the block's committees.
     if (equivocatingIndices.size > 0) {
       const state = this.fcStore.stateGetter({stateRoot: node.stateRoot});
-      // Only ever called on the head, so the state is always cached.
+      // Only ever called on the head or the boosted block's parent, so the state is always cached.
       // A miss is a broken invariant, not a recoverable state.
       if (state === null) {
         throw new ForkChoiceError({
@@ -1685,6 +1704,81 @@ export class ForkChoice implements IForkChoice {
     return this.fcStore.currentSlot === block.slot && isBeforeLateBlockCutoff;
   }
 
+  /**
+   * Return true if the block arrived before the PTC (payload-timeliness committee) deadline,
+   * ie. block_timeliness[PTC_TIMELINESS_INDEX]. should_apply_proposer_boost uses this as the
+   * definition of an "early" proposer equivocation: only a sibling seen by the PTC deadline
+   * proves the proposer equivocated soon enough that honest nodes could have withheld the boost.
+   *
+   * https://github.com/ethereum/consensus-specs/blob/v1.7.0-alpha.14/specs/gloas/fork-choice.md#modified-record_block_timeliness
+   *
+   * Child class can overwrite this for testing purpose.
+   */
+  protected isBlockPtcTimely(block: BeaconBlock, blockDelaySec: number): boolean {
+    const ptcThresholdMs = this.config.getSlotComponentDurationMs(this.config.PAYLOAD_ATTESTATION_DUE_BPS);
+    return this.fcStore.currentSlot === block.slot && blockDelaySec * 1000 < ptcThresholdMs;
+  }
+
+  /**
+   * Determine whether proposer boost should be applied to `proposerBoostRoot`.
+   *
+   * https://github.com/ethereum/consensus-specs/blob/v1.7.0-alpha.14/specs/gloas/fork-choice.md#new-should_apply_proposer_boost
+   *
+   * Pre-gloas blocks always receive the boost (unconditional, backward compatible). For gloas
+   * blocks the boost is withheld when the parent is a weak block from the previous slot and the
+   * proposer of that parent equivocated (published another PTC-timely block at the same slot).
+   */
+  private shouldApplyProposerBoost(): boolean {
+    if (!this.proposerBoostRoot) {
+      return false;
+    }
+
+    const boostedBlock = this.getBlockHexDefaultStatus(this.proposerBoostRoot);
+    // Pre-gloas blocks always get boost
+    if (!boostedBlock || !isGloasBlock(boostedBlock)) {
+      return true;
+    }
+
+    const parentBlock = this.getBlockHexDefaultStatus(boostedBlock.parentRoot);
+    if (!parentBlock) {
+      return true;
+    }
+
+    // Apply proposer boost if parent is not from the previous slot
+    if (parentBlock.slot + 1 < boostedBlock.slot) {
+      return true;
+    }
+
+    // Apply proposer boost if parent is not weak
+    if (!this.isHeadWeak(parentBlock.blockRoot)) {
+      return true;
+    }
+
+    // Parent is weak and from the previous slot: apply boost only if there are no early
+    // equivocations, ie. no other PTC-timely block at the parent's slot from the same proposer.
+    return !this.protoArray.hasEquivocatingBlock(parentBlock.proposerIndex, parentBlock.slot, parentBlock.blockRoot);
+  }
+
+  /**
+   * The proposer boost to apply to `proposerBoostRoot`, propagated up the branch by
+   * applyScoreChanges() together with the deltas.
+   */
+  private getProposerBoost(): {root: RootHex; score: bigint} | null {
+    if (!this.proposerBoostRoot) {
+      return null;
+    }
+
+    const proposerBoostScore =
+      this.justifiedProposerBoostScore ??
+      getCommitteeFraction(this.fcStore.justified.totalBalance, {
+        slotsPerEpoch: SLOTS_PER_EPOCH,
+        committeePercent: this.config.PROPOSER_SCORE_BOOST,
+      });
+    this.justifiedProposerBoostScore = proposerBoostScore;
+
+    return {root: this.proposerBoostRoot, score: proposerBoostScore};
+  }
+
   /**
    * https://github.com/ethereum/consensus-specs/blob/v1.5.0/specs/phase0/fork-choice.md#is_proposing_on_time
    */

packages/fork-choice/src/protoArray/interface.ts

@@ -1,5 +1,5 @@
 import {DataAvailabilityStatus} from "@lodestar/state-transition";
-import {Epoch, RootHex, Slot, UintNum64} from "@lodestar/types";
+import {Epoch, RootHex, Slot, UintNum64, ValidatorIndex} from "@lodestar/types";
 
 // RootHex is a root as a hex string
 // Used for lightweight and easy comparison
@@ -144,6 +144,13 @@ export type ProtoBlock = BlockExtraMeta & {
   // Indicate whether block arrives in a timely manner ie. before the 4 second mark
   timeliness: boolean;
 
+  // Indicate whether block arrives before the PTC deadline
+  // Spec: gloas/fork-choice.md#modified-record_block_timeliness (block_timeliness[PTC_TIMELINESS_INDEX])
+  ptcTimeliness: boolean;
+
+  // The index of the block proposer. Used by should_apply_proposer_boost to detect proposer equivocations
+  proposerIndex: ValidatorIndex;
+
   /** Payload status for this node (Gloas fork). Always FULL in pre-gloas */
   payloadStatus: PayloadStatus;
 

packages/fork-choice/src/protoArray/protoArray.ts

@@ -1,7 +1,7 @@
 import {BitArray} from "@chainsafe/ssz";
 import {EFFECTIVE_BALANCE_INCREMENT, GENESIS_EPOCH, GENESIS_SLOT, PTC_SIZE} from "@lodestar/params";
 import {DataAvailabilityStatus, computeEpochAtSlot, computeStartSlotAtEpoch} from "@lodestar/state-transition";
-import {Epoch, RootHex, Slot} from "@lodestar/types";
+import {Epoch, RootHex, Slot, ValidatorIndex} from "@lodestar/types";
 import {bitCount, toRootHex} from "@lodestar/utils";
 import {ForkChoiceError, ForkChoiceErrorCode} from "../forkChoice/errors.js";
 import {LVHExecError, LVHExecErrorCode, ProtoArrayError, ProtoArrayErrorCode} from "./errors.js";
@@ -2007,6 +2007,32 @@ export class ProtoArray {
     return this.getNodeByIndex(nodeIndex);
   }
 
+  /**
+   * Return true if a block other than `excludeRoot` at `slot` was proposed by `proposerIndex` and
+   * is PTC-timely. Used by `should_apply_proposer_boost` to detect proposer equivocations.
+   *
+   * https://github.com/ethereum/consensus-specs/blob/v1.7.0-alpha.14/specs/gloas/fork-choice.md#new-should_apply_proposer_boost
+   *
+   * Iterates unique block roots (via the canonical variant) since `slot`, `proposerIndex` and
+   * `ptcTimeliness` are block-level properties identical across payload-status variants.
+   */
+  hasEquivocatingBlock(proposerIndex: ValidatorIndex, slot: Slot, excludeRoot: RootHex): boolean {
+    for (const root of this.indices.keys()) {
+      if (root === excludeRoot) {
+        continue;
+      }
+      const nodeIndex = this.getDefaultNodeIndex(root);
+      if (nodeIndex === undefined) {
+        continue;
+      }
+      const node = this.nodes[nodeIndex];
+      if (node !== undefined && node.slot === slot && node.proposerIndex === proposerIndex && node.ptcTimeliness) {
+        return true;
+      }
+    }
+    return false;
+  }
+
   /**
    * Return MUTABLE ProtoBlock for blockRoot with explicit payload status
    *

packages/fork-choice/test/perf/forkChoice/updateHead.test.ts

@@ -22,9 +22,19 @@ describe("forkchoice updateHead", () => {
     runUpdateHeadBenchmark({initialValidatorCount: 600_000, initialBlockCount: 64, initialEquivocatedCount});
   }
 
+  // A boosted gloas block splits applyScoreChanges in two passes (attestation deltas, then the
+  // should_apply_proposer_boost decision, then boost deltas); measure that overhead against the
+  // single-pass `vc 600000 bc 64 eq 0` row above
+  runUpdateHeadBenchmark({
+    initialValidatorCount: 600_000,
+    initialBlockCount: 64,
+    initialEquivocatedCount: 0,
+    gloasBoosted: true,
+  });
+
   function runUpdateHeadBenchmark(opts: Opts): void {
     bench({
-      id: `forkChoice updateHead vc ${opts.initialValidatorCount} bc ${opts.initialBlockCount} eq ${opts.initialEquivocatedCount}`,
+      id: `forkChoice updateHead vc ${opts.initialValidatorCount} bc ${opts.initialBlockCount} eq ${opts.initialEquivocatedCount}${opts.gloasBoosted ? " gloas boosted" : ""}`,
       before: () => {
         const forkChoice = initializeForkChoice(opts);
 
@@ -43,7 +53,7 @@ describe("forkchoice updateHead", () => {
       },
       beforeEach: (data) => {
         // Flip all votes every run
-        everyoneVotes(data.currentVoteIs1 ? data.vote2 : data.vote1, data.forkChoice);
+        everyoneVotes(data.currentVoteIs1 ? data.vote2 : data.vote1, data.forkChoice, opts);
         data.currentVoteIs1 = !data.currentVoteIs1;
         return data;
       },
@@ -54,9 +64,11 @@ describe("forkchoice updateHead", () => {
   }
 });
 
-function everyoneVotes(vote: ProtoBlock, forkChoice: ForkChoice): void {
+function everyoneVotes(vote: ProtoBlock, forkChoice: ForkChoice, opts: Opts): void {
   const nextRoot = vote.blockRoot;
+  // gloas blocks only carry PENDING/EMPTY variants until the envelope is revealed
+  const payloadStatus = opts.gloasBoosted ? PayloadStatus.PENDING : PayloadStatus.FULL;
   for (let i = 0; i < forkChoice["balances"].length; i++) {
-    forkChoice["addLatestMessage"](i, vote.slot, nextRoot, PayloadStatus.FULL);
+    forkChoice["addLatestMessage"](i, vote.slot, nextRoot, payloadStatus);
   }
 }