feat(pipeline): allow syncing blocks ontop of the proposed chain

yarn-project/archiver/src/archiver.ts

@@ -19,7 +19,7 @@ import {
   type L2Tips,
   type ValidateCheckpointResult,
 } from '@aztec/stdlib/block';
-import { PublishedCheckpoint } from '@aztec/stdlib/checkpoint';
+import { type ProposedCheckpointInput, PublishedCheckpoint } from '@aztec/stdlib/checkpoint';
 import {
   type L1RollupConstants,
   getEpochAtSlot,
@@ -209,6 +209,10 @@ export class Archiver extends ArchiverDataSourceBase implements L2BlockSink, Tra
     });
   }
 
+  public async setProposedCheckpoint(pending: ProposedCheckpointInput): Promise<void> {
+    await this.updater.setProposedCheckpoint(pending);
+  }
+
   /**
    * Processes all queued blocks, adding them to the store.
    * Called at the beginning of each sync iteration.

yarn-project/archiver/src/errors.ts

@@ -26,9 +26,13 @@ export class InitialCheckpointNumberNotSequentialError extends Error {
 }
 
 export class CheckpointNumberNotSequentialError extends Error {
-  constructor(newCheckpointNumber: number, previous: number | undefined) {
+  constructor(
+    newCheckpointNumber: number,
+    previous: number | undefined,
+    source: 'confirmed' | 'proposed' = 'confirmed',
+  ) {
     super(
-      `Cannot insert new checkpoint ${newCheckpointNumber} given previous checkpoint number in batch is ${previous ?? 'undefined'}`,
+      `Cannot insert new checkpoint ${newCheckpointNumber} given previous ${source} checkpoint number is ${previous ?? 'undefined'}`,
     );
   }
 }
@@ -104,6 +108,30 @@ export class L1ToL2MessagesNotReadyError extends Error {
   }
 }
 
+/** Thrown when a proposed checkpoint number is stale (already processed). */
+export class ProposedCheckpointStaleError extends Error {
+  constructor(
+    public readonly proposedCheckpointNumber: number,
+    public readonly currentProposedNumber: number,
+  ) {
+    super(`Stale proposed checkpoint ${proposedCheckpointNumber}: current proposed is ${currentProposedNumber}`);
+    this.name = 'ProposedCheckpointStaleError';
+  }
+}
+
+/** Thrown when a proposed checkpoint number is not the expected confirmed + 1. */
+export class ProposedCheckpointNotSequentialError extends Error {
+  constructor(
+    public readonly proposedCheckpointNumber: number,
+    public readonly confirmedCheckpointNumber: number,
+  ) {
+    super(
+      `Proposed checkpoint ${proposedCheckpointNumber} is not sequential: expected ${confirmedCheckpointNumber + 1} (confirmed + 1)`,
+    );
+    this.name = 'ProposedCheckpointNotSequentialError';
+  }
+}
+
 /** Thrown when a proposed block conflicts with an already checkpointed block (different content). */
 export class CannotOverwriteCheckpointedBlockError extends Error {
   constructor(

yarn-project/archiver/src/modules/data_source_base.ts

@@ -6,7 +6,13 @@ import { isDefined } from '@aztec/foundation/types';
 import type { FunctionSelector } from '@aztec/stdlib/abi';
 import type { AztecAddress } from '@aztec/stdlib/aztec-address';
 import { type BlockData, type BlockHash, CheckpointedL2Block, L2Block, type L2Tips } from '@aztec/stdlib/block';
-import { Checkpoint, type CheckpointData, PublishedCheckpoint } from '@aztec/stdlib/checkpoint';
+import {
+  Checkpoint,
+  type CheckpointData,
+  type CommonCheckpointData,
+  type ProposedCheckpointData,
+  PublishedCheckpoint,
+} from '@aztec/stdlib/checkpoint';
 import type { ContractClassPublic, ContractDataSource, ContractInstanceWithAddress } from '@aztec/stdlib/contract';
 import { type L1RollupConstants, getSlotRangeForEpoch } from '@aztec/stdlib/epoch-helpers';
 import type { GetContractClassLogsResponse, GetPublicLogsResponse } from '@aztec/stdlib/interfaces/client';
@@ -157,6 +163,14 @@ export abstract class ArchiverDataSourceBase
     return this.store.getSettledTxReceipt(txHash, this.l1Constants);
   }
 
+  public getProposedCheckpoint(): Promise<CommonCheckpointData | undefined> {
+    return this.store.getProposedCheckpoint();
+  }
+
+  public getProposedCheckpointOnly(): Promise<ProposedCheckpointData | undefined> {
+    return this.store.getProposedCheckpointOnly();
+  }
+
   public isPendingChainInvalid(): Promise<boolean> {
     return this.getPendingChainValidationStatus().then(status => !status.valid);
   }

yarn-project/archiver/src/modules/data_store_updater.ts

@@ -7,7 +7,7 @@ import {
   ContractInstanceUpdatedEvent,
 } from '@aztec/protocol-contracts/instance-registry';
 import type { L2Block, ValidateCheckpointResult } from '@aztec/stdlib/block';
-import { type PublishedCheckpoint, validateCheckpoint } from '@aztec/stdlib/checkpoint';
+import { type ProposedCheckpointInput, type PublishedCheckpoint, validateCheckpoint } from '@aztec/stdlib/checkpoint';
 import {
   type ContractClassPublicWithCommitment,
   computeContractAddressFromInstance,
@@ -118,6 +118,15 @@ export class ArchiverDataStoreUpdater {
     return result;
   }
 
+  public async setProposedCheckpoint(proposedCheckpoint: ProposedCheckpointInput) {
+    const result = await this.store.transactionAsync(async () => {
+      await this.store.setProposedCheckpoint(proposedCheckpoint);
+      await this.l2TipsCache?.refresh();
+    });
+
+    return result;
+  }
+
   /**
    * Checks for local proposed blocks that do not match the ones to be checkpointed and prunes them.
    * This method handles multiple checkpoints but returns after pruning the first conflict found.
@@ -211,6 +220,10 @@ export class ArchiverDataStoreUpdater {
       }
 
       const result = await this.removeBlocksAfter(blockNumber);
+
+      // Clear the proposed checkpoint if it exists, since its blocks have been pruned
+      await this.store.deleteProposedCheckpoint();
+
       await this.l2TipsCache?.refresh();
       return result;
     });

yarn-project/archiver/src/modules/l1_synchronizer.ts

@@ -269,29 +269,32 @@ export class ArchiverL1Synchronizer implements Traceable {
       return;
     }
 
-    // What's the slot of the first uncheckpointed block?
+    // What's the slot at the next L1 block? All blocks for slots strictly before this one should've been checkpointed by now.
+    const slotAtNextL1Block = getSlotAtNextL1Block(currentL1Timestamp, this.l1Constants);
     const firstUncheckpointedBlockNumber = BlockNumber(lastCheckpointedBlockNumber + 1);
+
+    // What's the slot of the first uncheckpointed block?
     const [firstUncheckpointedBlockHeader] = await this.store.getBlockHeaders(firstUncheckpointedBlockNumber, 1);
     const firstUncheckpointedBlockSlot = firstUncheckpointedBlockHeader?.getSlot();
 
-    // What's the slot at the next L1 block? All blocks for slots strictly before this one should've been checkpointed by now.
-    const slotAtNextL1Block = getSlotAtNextL1Block(currentL1Timestamp, this.l1Constants);
+    if (firstUncheckpointedBlockSlot === undefined || firstUncheckpointedBlockSlot >= slotAtNextL1Block) {
+      return;
+    }
 
-    // Prune provisional blocks from slots that have ended without being checkpointed
-    if (firstUncheckpointedBlockSlot !== undefined && firstUncheckpointedBlockSlot < slotAtNextL1Block) {
-      this.log.warn(
-        `Pruning blocks after block ${lastCheckpointedBlockNumber} due to slot ${firstUncheckpointedBlockSlot} not being checkpointed`,
-        { firstUncheckpointedBlockHeader: firstUncheckpointedBlockHeader.toInspect(), slotAtNextL1Block },
-      );
-      const prunedBlocks = await this.updater.removeUncheckpointedBlocksAfter(lastCheckpointedBlockNumber);
+    // Prune provisional blocks from slots that have ended without being checkpointed.
+    // This also clears any proposed checkpoint whose blocks are being pruned.
+    this.log.warn(
+      `Pruning blocks after block ${lastCheckpointedBlockNumber} due to slot ${firstUncheckpointedBlockSlot} not being checkpointed`,
+      { firstUncheckpointedBlockHeader: firstUncheckpointedBlockHeader.toInspect(), slotAtNextL1Block },
+    );
+    const prunedBlocks = await this.updater.removeUncheckpointedBlocksAfter(lastCheckpointedBlockNumber);
 
-      if (prunedBlocks.length > 0) {
-        this.events.emit(L2BlockSourceEvents.L2PruneUncheckpointed, {
-          type: L2BlockSourceEvents.L2PruneUncheckpointed,
-          slotNumber: firstUncheckpointedBlockSlot,
-          blocks: prunedBlocks,
-        });
-      }
+    if (prunedBlocks.length > 0) {
+      this.events.emit(L2BlockSourceEvents.L2PruneUncheckpointed, {
+        type: L2BlockSourceEvents.L2PruneUncheckpointed,
+        slotNumber: firstUncheckpointedBlockSlot,
+        blocks: prunedBlocks,
+      });
     }
   }
 

yarn-project/archiver/src/modules/validation.ts

@@ -9,7 +9,7 @@ import {
   getAttestationInfoFromPayload,
 } from '@aztec/stdlib/block';
 import type { PublishedCheckpoint } from '@aztec/stdlib/checkpoint';
-import { type L1RollupConstants, getEpochAtSlot } from '@aztec/stdlib/epoch-helpers';
+import { type L1RollupConstants, computeQuorum, getEpochAtSlot } from '@aztec/stdlib/epoch-helpers';
 import { ConsensusPayload } from '@aztec/stdlib/p2p';
 
 export type { ValidateCheckpointResult };
@@ -66,7 +66,7 @@ export async function validateCheckpointAttestations(
     return { valid: true };
   }
 
-  const requiredAttestationCount = Math.floor((committee.length * 2) / 3) + 1;
+  const requiredAttestationCount = computeQuorum(committee.length);
 
   const failedValidationResult = <TReason extends ValidateCheckpointNegativeResult['reason']>(reason: TReason) => ({
     valid: false as const,