fix: recompute head after pulling up checkpoints

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

@@ -102,11 +102,6 @@ export const defaultSkipOpts: SkipOpts = {
     // TODO-GLOAS: re-enable after gloas light client is implemented
     /\/gloas_fork$/,
     /\/heze_fork$/,
-    // TODO GLOAS: Proposer-boost dependent-root gate uses stale cached head across epoch-boundary ticks;
-    // boost wrongly denied. Fails identically on every pre-gloas fork.
-    // Enable this after https://github.com/ChainSafe/lodestar/issues/9666 is resolved
-    // The case name embeds the generation seed, so it changes whenever comptests are regenerated.
-    /fork_choice_compliance\/block_tree_test\/pyspec_tests\/block_tree_test_17_381675768_1$/,
     // TODO GLOAS: gloas/heze take ~23-24s on the mainnet preset (~7.5x pre-gloas) because every
     // post-gloas slot writes into the SLOTS_PER_HISTORICAL_ROOT-wide executionPayloadAvailability
     // bitvector, and this suite steps 8192 slots. That is 76-81% of the 30s sanity/slots timeout,

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

@@ -1081,11 +1081,20 @@ export class ForkChoice implements IForkChoice {
     while (this.fcStore.currentSlot < currentSlot) {
       const previousSlot = this.fcStore.currentSlot;
       // Note: we are relying upon `onTick` to update `fcStore.time` to ensure we don't get stuck in a loop.
-      this.onTick(previousSlot + 1);
+      const didUpdateCheckpoints = this.onTick(previousSlot + 1);
       this.queuedAttestationsPreviousSlot = 0;
       // Process any attestations that might now be eligible before running FCR for this slot.
       this.processAttestationQueue();
-      this.runFastConfirmation();
+      const didRecomputeHead = this.runFastConfirmation();
+
+      // An epoch-boundary checkpoint pull-up can move the head's dependent root and stale the cached
+      // head before block 0 of the new epoch is imported, making isProposerBoostSameDependentRoot()
+      // wrong for that block. Recompute the head so it reflects the new checkpoint and the queued
+      // votes — unless fast confirmation already did, to avoid a redundant head calculation.
+      if (didUpdateCheckpoints && !didRecomputeHead) {
+        this.updateHead();
+      }
+
       this.validatedAttestationDatas = new Set();
     }
   }
@@ -1732,23 +1741,31 @@ export class ForkChoice implements IForkChoice {
    * May need the justified balances of:
    * - unrealizedJustified: Already available in `CheckpointWithBalance`
    * Since this balances are already available the getter is just `() => balances`, without cache interaction
+   *
+   * @returns Whether either checkpoint was updated.
    */
   private updateCheckpoints(
     justifiedCheckpoint: CheckpointWithHex,
     finalizedCheckpoint: CheckpointWithHex,
     getJustifiedBalances: () => JustifiedBalances
-  ): void {
+  ): boolean {
+    let updated = false;
+
     // Update justified checkpoint.
     if (justifiedCheckpoint.epoch > this.fcStore.justified.checkpoint.epoch) {
       this.fcStore.justified = {checkpoint: justifiedCheckpoint, balances: getJustifiedBalances()};
       this.justifiedProposerBoostScore = null;
+      updated = true;
     }
 
     // Update finalized checkpoint.
     if (finalizedCheckpoint.epoch > this.fcStore.finalizedCheckpoint.epoch) {
       this.fcStore.finalizedCheckpoint = finalizedCheckpoint;
       this.justifiedProposerBoostScore = null;
+      updated = true;
     }
+
+    return updated;
   }
 
   /**
@@ -2034,8 +2051,10 @@ export class ForkChoice implements IForkChoice {
    * Equivalent to:
    *
    * https://github.com/ethereum/consensus-specs/blob/v1.1.10/specs/phase0/fork-choice.md#on_tick
+   *
+   * @returns Whether an epoch-boundary checkpoint was updated.
    */
-  private onTick(time: Slot): void {
+  private onTick(time: Slot): boolean {
     const previousSlot = this.fcStore.currentSlot;
 
     if (time > previousSlot + 1) {
@@ -2056,11 +2075,11 @@ export class ForkChoice implements IForkChoice {
 
     // Not a new epoch, return.
     if (computeSlotsSinceEpochStart(time) !== 0) {
-      return;
+      return false;
     }
 
-    // If a new epoch, pull-up justification and finalization from previous epoch
-    this.updateCheckpoints(
+    // If a new epoch, pull-up justification and finalization from previous epoch.
+    return this.updateCheckpoints(
       this.fcStore.unrealizedJustified.checkpoint,
       this.fcStore.unrealizedFinalizedCheckpoint,
       () => this.fcStore.unrealizedJustified.balances
@@ -2119,10 +2138,11 @@ export class ForkChoice implements IForkChoice {
     return {prelimProposerHead};
   }
 
-  private runFastConfirmation(): void {
+  /** Returns whether it recomputed the head, so the caller can avoid a redundant `updateHead()`. */
+  private runFastConfirmation(): boolean {
     const fastConfirmationRule = this.fastConfirmationRule;
     const fastConfirmationContext = this.fastConfirmationContext;
-    if (!fastConfirmationRule || !fastConfirmationContext) return;
+    if (!fastConfirmationRule || !fastConfirmationContext) return false;
 
     if (this.fastConfirmationPaused) {
       // Keep consumers on a safe, available root while the rule is paused
@@ -2133,7 +2153,7 @@ export class ForkChoice implements IForkChoice {
         // Runs outside the timed try/catch below; a throw would escape to the clock listener
         this.logger?.debug("Fast confirmation notify failed", {slot: this.fcStore.currentSlot}, err as Error);
       }
-      return;
+      return false;
     }
 
     withObservedDuration(this.metrics?.fastConfirmation.totalDuration.startTimer(), () => {
@@ -2156,6 +2176,8 @@ export class ForkChoice implements IForkChoice {
         );
       }
     });
+
+    return true;
   }
 
   private createFastConfirmationContext(): FastConfirmationContext {