refactor: updating block hash to be header.hash() (AztecProtocol#4286)

Fixes AztecProtocol#3941
+ renamed AppendOnlyTreeSnapshot.empty() as
AppendOnlyTreeSnapshot.zero() to have it consistent with Noir

**Note**: I did a large refactor of `MerkleTrees` class because with
this change a lot of stuff there just didn't make sense anymore. Overall
I think it's much cleaner now.

l1-contracts/src/periphery/ContractDeploymentEmitter.sol

@@ -23,7 +23,7 @@ contract ContractDeploymentEmitter is IContractDeploymentEmitter {
    * @param _saltedInitializationHash - Salted init hash
    * @param _publicKeyHash - Public key hash
    * @param _acir - The acir bytecode of the L2 contract
-   * @dev See the link bellow for more info on partial address and public key:
+   * @dev See the link below for more info on partial address and public key:
    * https://github.com/AztecProtocol/aztec-packages/blob/master/docs/docs/concepts/foundation/accounts/keys.md#addresses-partial-addresses-and-public-keys
    * TODO: replace the link above with the link to deployed docs
    */

l1-contracts/src/periphery/interfaces/IContractDeploymentEmitter.sol

@@ -19,7 +19,7 @@ interface IContractDeploymentEmitter {
    * @param saltedInitializationHash - Salted init hash
    * @param publicKeyHash - Public key hash
    * @param acir - The acir bytecode of the L2 contract
-   * @dev See the link bellow for more info on partial address and public key:
+   * @dev See the link below for more info on partial address and public key:
    * https://github.com/AztecProtocol/aztec-packages/blob/master/docs/docs/concepts/foundation/accounts/keys.md#addresses-partial-addresses-and-public-keys
    * TODO: replace the link above with the link to deployed docs
    */

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

@@ -297,11 +297,7 @@ export class Archiver implements ArchiveSource {
       retrievedBlocks.retrievedData.map(block => {
         // Ensure we pad the L1 to L2 message array to the full size before storing.
         block.newL1ToL2Messages = padArrayEnd(block.newL1ToL2Messages, Fr.ZERO, NUMBER_OF_L1_L2_MESSAGES_PER_ROLLUP);
-        return L2Block.fromFields(
-          omit(block, ['newEncryptedLogs', 'newUnencryptedLogs']),
-          block.getBlockHash(),
-          block.getL1BlockNumber(),
-        );
+        return L2Block.fromFields(omit(block, ['newEncryptedLogs', 'newUnencryptedLogs']), block.getL1BlockNumber());
       }),
     );
   }

yarn-project/archiver/src/archiver/kv_archiver_store/block_store.ts

@@ -9,7 +9,6 @@ type BlockContext = {
   blockNumber: number;
   l1BlockNumber: bigint;
   block: Buffer;
-  blockHash: Buffer;
 };
 
 /**
@@ -46,7 +45,6 @@ export class BlockStore {
           blockNumber: block.number,
           block: block.toBuffer(),
           l1BlockNumber: block.getL1BlockNumber(),
-          blockHash: block.getBlockHash(),
         });
 
         for (const [i, tx] of block.getTxs().entries()) {
@@ -77,7 +75,7 @@ export class BlockStore {
    */
   *getBlocks(start: number, limit: number): IterableIterator<L2Block> {
     for (const blockCtx of this.#blocks.values(this.#computeBlockRange(start, limit))) {
-      yield L2Block.fromBuffer(blockCtx.block, blockCtx.blockHash);
+      yield L2Block.fromBuffer(blockCtx.block);
     }
   }
 
@@ -92,9 +90,7 @@ export class BlockStore {
       return undefined;
     }
 
-    const block = L2Block.fromBuffer(blockCtx.block, blockCtx.blockHash);
-
-    return block;
+    return L2Block.fromBuffer(blockCtx.block);
   }
 
   /**

yarn-project/aztec-node/src/aztec-node/server.ts

@@ -26,7 +26,6 @@ import {
   ARCHIVE_HEIGHT,
   CONTRACT_TREE_HEIGHT,
   Fr,
-  GlobalVariables,
   Header,
   L1_TO_L2_MSG_TREE_HEIGHT,
   NOTE_HASH_TREE_HEIGHT,
@@ -35,7 +34,7 @@ import {
   PUBLIC_DATA_TREE_HEIGHT,
   PublicDataTreeLeafPreimage,
 } from '@aztec/circuits.js';
-import { computeGlobalsHash, computePublicDataTreeLeafSlot } from '@aztec/circuits.js/abis';
+import { computePublicDataTreeLeafSlot } from '@aztec/circuits.js/abis';
 import { L1ContractAddresses, createEthereumChain } from '@aztec/ethereum';
 import { AztecAddress } from '@aztec/foundation/aztec-address';
 import { createDebugLogger } from '@aztec/foundation/log';
@@ -45,7 +44,6 @@ import {
   GlobalVariableBuilder,
   PublicProcessorFactory,
   SequencerClient,
-  buildInitialHeader,
   getGlobalVariableBuilder,
 } from '@aztec/sequencer-client';
 import { SiblingPath } from '@aztec/types/membership';
@@ -537,7 +535,7 @@ export class AztecNodeService implements AztecNode {
 
     // No block was not found so we build the initial header.
     const committedDb = await this.#getWorldState('latest');
-    return await buildInitialHeader(committedDb);
+    return await committedDb.buildInitialHeader();
   }
 
   /**
@@ -549,16 +547,11 @@ export class AztecNodeService implements AztecNode {
     const blockNumber = (await this.blockSource.getBlockNumber()) + 1;
     const newGlobalVariables = await this.globalVariableBuilder.buildGlobalVariables(new Fr(blockNumber));
     const prevHeader = (await this.blockSource.getBlock(-1))?.header;
-    const prevGlobalVariables = prevHeader?.globalVariables ?? GlobalVariables.empty();
 
     // Instantiate merkle trees so uncommitted updates by this simulation are local to it.
     // TODO we should be able to remove this after https://github.com/AztecProtocol/aztec-packages/issues/1869
     // So simulation of public functions doesn't affect the merkle trees.
-    const merkleTrees = new MerkleTrees(this.merkleTreesDb, this.log);
-    const globalVariablesHash = computeGlobalsHash(prevGlobalVariables);
-    await merkleTrees.init({
-      globalVariablesHash,
-    });
+    const merkleTrees = await MerkleTrees.new(this.merkleTreesDb, this.log);
 
     const publicProcessorFactory = new PublicProcessorFactory(
       merkleTrees.asLatest(),

yarn-project/aztec-nr/aztec/src/oracle/header.nr

@@ -40,7 +40,7 @@ pub fn get_header_at(block_number: u32, context: PrivateContext) -> Header {
         let header = get_header_at_internal(block_number);
 
         // 4) Compute the block hash from the block header
-        let block_hash = header.block_hash();
+        let block_hash = header.hash();
 
         // 5) Get the membership witness of the block in the archive
         let witness = get_archive_membership_witness(last_archive_block_number, block_hash);

yarn-project/circuit-types/src/l2_block.ts

@@ -11,7 +11,7 @@ import {
 } from '@aztec/circuits.js';
 import { makeAppendOnlyTreeSnapshot, makeHeader } from '@aztec/circuits.js/factories';
 import { times } from '@aztec/foundation/collection';
-import { keccak, sha256 } from '@aztec/foundation/crypto';
+import { sha256 } from '@aztec/foundation/crypto';
 import { Fr } from '@aztec/foundation/fields';
 import { createDebugLogger } from '@aztec/foundation/log';
 import { BufferReader, serializeToBuffer } from '@aztec/foundation/serialize';
@@ -91,7 +91,6 @@ export class L2Block {
     public newL1ToL2Messages: Fr[] = [],
     newEncryptedLogs?: L2BlockL2Logs,
     newUnencryptedLogs?: L2BlockL2Logs,
-    private blockHash?: Buffer,
     l1BlockNumber?: bigint,
   ) {
     if (newCommitments.length % MAX_NEW_COMMITMENTS_PER_TX !== 0) {
@@ -173,7 +172,6 @@ export class L2Block {
         newEncryptedLogs,
         newUnencryptedLogs,
       },
-      undefined,
       // just for testing purposes, each random L2 block got emitted in the equivalent L1 block
       BigInt(l2BlockNum),
     );
@@ -229,7 +227,6 @@ export class L2Block {
        */
       newUnencryptedLogs?: L2BlockL2Logs;
     },
-    blockHash?: Buffer,
     l1BlockNumber?: bigint,
   ) {
     return new this(
@@ -244,7 +241,6 @@ export class L2Block {
       fields.newL1ToL2Messages,
       fields.newEncryptedLogs,
       fields.newUnencryptedLogs,
-      blockHash,
       l1BlockNumber,
     );
   }
@@ -329,10 +325,9 @@ export class L2Block {
   /**
    * Deserializes L2 block without logs from a buffer.
    * @param buf - A serialized L2 block.
-   * @param blockHash - The hash of the block.
    * @returns Deserialized L2 block.
    */
-  static fromBuffer(buf: Buffer | BufferReader, blockHash?: Buffer) {
+  static fromBuffer(buf: Buffer | BufferReader) {
     const reader = BufferReader.asReader(buf);
     const header = reader.readObject(Header);
     const archive = reader.readObject(AppendOnlyTreeSnapshot);
@@ -345,20 +340,17 @@ export class L2Block {
     // TODO(sean): could an optimization of this be that it is encoded such that zeros are assumed
     const newL1ToL2Messages = reader.readVector(Fr);
 
-    return L2Block.fromFields(
-      {
-        archive,
-        header,
-        newCommitments,
-        newNullifiers,
-        newPublicDataWrites,
-        newL2ToL1Msgs,
-        newContracts,
-        newContractData,
-        newL1ToL2Messages,
-      },
-      blockHash,
-    );
+    return L2Block.fromFields({
+      archive,
+      header,
+      newCommitments,
+      newNullifiers,
+      newPublicDataWrites,
+      newL2ToL1Msgs,
+      newContracts,
+      newContractData,
+      newL1ToL2Messages,
+    });
   }
 
   /**
@@ -441,14 +433,11 @@ export class L2Block {
   }
 
   /**
-   * Returns the block's hash.
+   * Returns the block's hash (hash of block header).
    * @returns The block's hash.
    */
-  public getBlockHash(): Buffer {
-    if (!this.blockHash) {
-      this.blockHash = keccak(this.toBufferWithLogs());
-    }
-    return this.blockHash;
+  public hash(): Fr {
+    return this.header.hash();
   }
 
   /**
@@ -460,11 +449,11 @@ export class L2Block {
     const buf = serializeToBuffer(
       this.header.globalVariables,
       // TODO(#3868)
-      AppendOnlyTreeSnapshot.empty(), // this.startNoteHashTreeSnapshot,
-      AppendOnlyTreeSnapshot.empty(), // this.startNullifierTreeSnapshot,
-      AppendOnlyTreeSnapshot.empty(), // this.startContractTreeSnapshot,
-      AppendOnlyTreeSnapshot.empty(), // this.startPublicDataTreeSnapshot,
-      AppendOnlyTreeSnapshot.empty(), // this.startL1ToL2MessageTreeSnapshot,
+      AppendOnlyTreeSnapshot.zero(), // this.startNoteHashTreeSnapshot,
+      AppendOnlyTreeSnapshot.zero(), // this.startNullifierTreeSnapshot,
+      AppendOnlyTreeSnapshot.zero(), // this.startContractTreeSnapshot,
+      AppendOnlyTreeSnapshot.zero(), // this.startPublicDataTreeSnapshot,
+      AppendOnlyTreeSnapshot.zero(), // this.startL1ToL2MessageTreeSnapshot,
       this.header.lastArchive,
       this.header.state.partial.noteHashTree,
       this.header.state.partial.nullifierTree,
@@ -487,11 +476,11 @@ export class L2Block {
     const inputValue = serializeToBuffer(
       new Fr(Number(this.header.globalVariables.blockNumber.toBigInt()) - 1),
       // TODO(#3868)
-      AppendOnlyTreeSnapshot.empty(), // this.startNoteHashTreeSnapshot,
-      AppendOnlyTreeSnapshot.empty(), // this.startNullifierTreeSnapshot,
-      AppendOnlyTreeSnapshot.empty(), // this.startContractTreeSnapshot,
-      AppendOnlyTreeSnapshot.empty(), // this.startPublicDataTreeSnapshot,
-      AppendOnlyTreeSnapshot.empty(), // this.startL1ToL2MessageTreeSnapshot,
+      AppendOnlyTreeSnapshot.zero(), // this.startNoteHashTreeSnapshot,
+      AppendOnlyTreeSnapshot.zero(), // this.startNullifierTreeSnapshot,
+      AppendOnlyTreeSnapshot.zero(), // this.startContractTreeSnapshot,
+      AppendOnlyTreeSnapshot.zero(), // this.startPublicDataTreeSnapshot,
+      AppendOnlyTreeSnapshot.zero(), // this.startL1ToL2MessageTreeSnapshot,
       this.header.lastArchive,
     );
     return sha256(inputValue);
@@ -639,7 +628,7 @@ export class L2Block {
       newL2ToL1Msgs,
       newContracts,
       newContractData,
-      this.getBlockHash(),
+      this.hash(),
       Number(this.header.globalVariables.blockNumber.toBigInt()),
     );
   }

yarn-project/circuit-types/src/l2_tx.ts

@@ -57,7 +57,7 @@ export class L2Tx {
     /**
      * The unique identifier of the block containing the transaction.
      */
-    public blockHash: Buffer,
+    public blockHash: Fr,
     /**
      * The block number in which the transaction was included.
      */
@@ -80,7 +80,7 @@ export class L2Tx {
       reader.readVector(Fr),
       reader.readVector(Fr),
       reader.readVector(ContractData),
-      reader.readBytes(Fr.SIZE_IN_BYTES),
+      Fr.fromBuffer(reader),
       reader.readNumber(),
     );
   }
@@ -106,7 +106,7 @@ export class L2Tx {
       new Vector(this.newL2ToL1Msgs).toBuffer(),
       new Vector(this.newContracts).toBuffer(),
       new Vector(this.newContractData).toBuffer(),
-      this.blockHash,
+      this.blockHash.toBuffer(),
       numToUInt32BE(this.blockNumber),
     ]);
   }
@@ -127,7 +127,7 @@ export class L2Tx {
       times(rand(0, MAX_NEW_L2_TO_L1_MSGS_PER_TX), Fr.random),
       times(rand(0, MAX_NEW_CONTRACTS_PER_TX), Fr.random),
       times(rand(0, MAX_NEW_CONTRACTS_PER_TX), ContractData.random),
-      Fr.random().toBuffer(),
+      Fr.random(),
       123,
     );
   }