feat(avm-simulator): fix L1TOL2MESSAGEEXISTS opcode

yarn-project/pxe/src/simulator_oracle/index.ts

@@ -159,6 +159,11 @@ export class SimulatorOracle implements DBOracle {
     return new MessageLoadOracleInputs(messageIndex, siblingPath);
   }
 
+  // Only used in public.
+  public getL1ToL2LeafValue(_leafIndex: bigint): Promise<Fr | undefined> {
+    throw new Error('Unimplemented in private!');
+  }
+
   /**
    * Gets the index of a commitment in the note hash tree.
    * @param commitment - The commitment.

yarn-project/simulator/src/avm/avm_simulator.test.ts

@@ -20,7 +20,6 @@ import {
   initContext,
   initExecutionEnvironment,
   initGlobalVariables,
-  initL1ToL2MessageOracleInput,
   initMachineState,
   randomMemoryBytes,
   randomMemoryFields,
@@ -484,9 +483,7 @@ describe('AVM simulator: transpiled Noir contracts', () => {
       const calldata = [msgHash, leafIndex];
 
       const context = initContext({ env: initExecutionEnvironment({ calldata }) });
-      jest
-        .spyOn(context.persistableState.hostStorage.commitmentsDb, 'getL1ToL2MembershipWitness')
-        .mockResolvedValue(initL1ToL2MessageOracleInput(leafIndex.toBigInt()));
+      jest.spyOn(context.persistableState.hostStorage.commitmentsDb, 'getL1ToL2LeafValue').mockResolvedValue(msgHash);
       const bytecode = getAvmTestContractBytecode('l1_to_l2_msg_exists');
       const results = await new AvmSimulator(context).executeBytecode(bytecode);
 

yarn-project/simulator/src/avm/fixtures/index.ts

@@ -1,5 +1,4 @@
-import { SiblingPath } from '@aztec/circuit-types';
-import { GasFees, GasSettings, GlobalVariables, Header, L1_TO_L2_MSG_TREE_HEIGHT } from '@aztec/circuits.js';
+import { GasFees, GasSettings, GlobalVariables, Header } from '@aztec/circuits.js';
 import { FunctionSelector } from '@aztec/foundation/abi';
 import { AztecAddress } from '@aztec/foundation/aztec-address';
 import { EthAddress } from '@aztec/foundation/eth-address';
@@ -8,12 +7,7 @@ import { Fr } from '@aztec/foundation/fields';
 import { mock } from 'jest-mock-extended';
 import merge from 'lodash.merge';
 
-import {
-  type CommitmentsDB,
-  MessageLoadOracleInputs,
-  type PublicContractsDB,
-  type PublicStateDB,
-} from '../../index.js';
+import { type CommitmentsDB, type PublicContractsDB, type PublicStateDB } from '../../index.js';
 import { AvmContext } from '../avm_context.js';
 import { AvmContextInputs, AvmExecutionEnvironment } from '../avm_execution_environment.js';
 import { AvmMachineState } from '../avm_machine_state.js';
@@ -111,18 +105,6 @@ export function allSameExcept(original: any, overrides: any): any {
   return merge({}, original, overrides);
 }
 
-/**
- * Create an empty L1ToL2Message oracle input
- */
-export function initL1ToL2MessageOracleInput(
-  leafIndex?: bigint,
-): MessageLoadOracleInputs<typeof L1_TO_L2_MSG_TREE_HEIGHT> {
-  return new MessageLoadOracleInputs<typeof L1_TO_L2_MSG_TREE_HEIGHT>(
-    leafIndex ?? 0n,
-    new SiblingPath(L1_TO_L2_MSG_TREE_HEIGHT, Array(L1_TO_L2_MSG_TREE_HEIGHT)),
-  );
-}
-
 /**
  * Adjust the user index to account for the AvmContextInputs size.
  * This is a hack for testing, and should go away once AvmContextInputs themselves go away.

yarn-project/simulator/src/avm/journal/journal.test.ts

@@ -6,7 +6,6 @@ import { Fr } from '@aztec/foundation/fields';
 import { type MockProxy, mock } from 'jest-mock-extended';
 
 import { type CommitmentsDB, type PublicContractsDB, type PublicStateDB } from '../../index.js';
-import { initL1ToL2MessageOracleInput } from '../fixtures/index.js';
 import { HostStorage } from './host_storage.js';
 import { AvmPersistableStateManager, type JournalData } from './journal.js';
 
@@ -129,7 +128,7 @@ describe('journal', () => {
       const utxo = new Fr(2);
       const leafIndex = new Fr(42);
 
-      commitmentsDb.getL1ToL2MembershipWitness.mockResolvedValue(initL1ToL2MessageOracleInput(leafIndex.toBigInt()));
+      commitmentsDb.getL1ToL2LeafValue.mockResolvedValue(utxo);
       const exists = await journal.checkL1ToL2MessageExists(utxo, leafIndex);
       expect(exists).toEqual(true);
 

yarn-project/simulator/src/avm/journal/journal.ts

@@ -1,7 +1,7 @@
 import { UnencryptedL2Log } from '@aztec/circuit-types';
 import { AztecAddress, EthAddress, L2ToL1Message } from '@aztec/circuits.js';
 import { EventSelector } from '@aztec/foundation/abi';
-import { Fr } from '@aztec/foundation/fields';
+import { type Fr } from '@aztec/foundation/fields';
 import { type DebugLogger, createDebugLogger } from '@aztec/foundation/log';
 
 import { type HostStorage } from './host_storage.js';
@@ -171,24 +171,11 @@ export class AvmPersistableStateManager {
    * @returns exists - whether the message exists in the L1 to L2 Messages tree
    */
   public async checkL1ToL2MessageExists(msgHash: Fr, msgLeafIndex: Fr): Promise<boolean> {
-    let exists = false;
-    try {
-      // The following 2 values are used to compute a message nullifier. Given that here we do not care about getting
-      // non-nullified messages we can just pass in random values and the nullifier check will effectively be ignored
-      // (no nullifier will be found).
-      const ignoredContractAddress = AztecAddress.random();
-      const ignoredSecret = Fr.random();
-      const gotMessage = await this.hostStorage.commitmentsDb.getL1ToL2MembershipWitness(
-        ignoredContractAddress,
-        msgHash,
-        ignoredSecret,
-      );
-      exists = gotMessage !== undefined && gotMessage.index == msgLeafIndex.toBigInt();
-    } catch {
-      // error getting message - doesn't exist!
-      exists = false;
-    }
-    this.log.debug(`l1ToL2Messages(${msgHash})@${msgLeafIndex} ?? exists: ${exists}.`);
+    const valueAtIndex = await this.hostStorage.commitmentsDb.getL1ToL2LeafValue(msgLeafIndex.toBigInt());
+    const exists = valueAtIndex?.equals(msgHash) ?? false;
+    this.log.debug(
+      `l1ToL2Messages(@${msgLeafIndex}) ?? exists: ${exists}, expected: ${msgHash}, found: ${valueAtIndex}.`,
+    );
     this.trace.traceL1ToL2MessageCheck(msgHash, msgLeafIndex, exists);
     return Promise.resolve(exists);
   }

yarn-project/simulator/src/avm/opcodes/accrued_substate.test.ts

@@ -8,12 +8,7 @@ import { type CommitmentsDB } from '../../index.js';
 import { type AvmContext } from '../avm_context.js';
 import { Field, Uint8 } from '../avm_memory_types.js';
 import { InstructionExecutionError } from '../errors.js';
-import {
-  initContext,
-  initExecutionEnvironment,
-  initHostStorage,
-  initL1ToL2MessageOracleInput,
-} from '../fixtures/index.js';
+import { initContext, initExecutionEnvironment, initHostStorage } from '../fixtures/index.js';
 import { AvmPersistableStateManager } from '../journal/journal.js';
 import {
   EmitNoteHash,
@@ -348,15 +343,14 @@ describe('Accrued Substate', () => {
 
       // mock commitments db to show message exists
       const commitmentsDb = mock<CommitmentsDB>();
-      commitmentsDb.getL1ToL2MembershipWitness.mockResolvedValue(initL1ToL2MessageOracleInput(leafIndex.toBigInt()));
+      commitmentsDb.getL1ToL2LeafValue.mockResolvedValue(msgHash.toFr());
       const hostStorage = initHostStorage({ commitmentsDb });
       context = initContext({ persistableState: new AvmPersistableStateManager(hostStorage) });
 
       context.machineState.memory.set(msgHashOffset, msgHash);
       context.machineState.memory.set(msgLeafIndexOffset, leafIndex);
       await new L1ToL2MessageExists(/*indirect=*/ 0, msgHashOffset, msgLeafIndexOffset, existsOffset).execute(context);
 
-      // never created, doesn't exist!
       const exists = context.machineState.memory.getAs<Uint8>(existsOffset);
       expect(exists).toEqual(new Uint8(1));
 
@@ -365,6 +359,33 @@ describe('Accrued Substate', () => {
         expect.objectContaining({ leafIndex: leafIndex.toFr(), msgHash: msgHash.toFr(), exists: true }),
       ]);
     });
+
+    it('Should correctly show false when another L1ToL2 message exists at that leaf', async () => {
+      const msgHash = new Field(69n);
+      const leafIndex = new Field(42n);
+      const msgHashOffset = 0;
+      const msgLeafIndexOffset = 1;
+      const existsOffset = 2;
+
+      // mock commitments db to show message exists
+      const commitmentsDb = mock<CommitmentsDB>();
+      commitmentsDb.getL1ToL2LeafValue.mockResolvedValue(Fr.ZERO);
+      const hostStorage = initHostStorage({ commitmentsDb });
+      context = initContext({ persistableState: new AvmPersistableStateManager(hostStorage) });
+
+      context.machineState.memory.set(msgHashOffset, msgHash);
+      context.machineState.memory.set(msgLeafIndexOffset, leafIndex);
+      await new L1ToL2MessageExists(/*indirect=*/ 0, msgHashOffset, msgLeafIndexOffset, existsOffset).execute(context);
+
+      // never created, doesn't exist!
+      const exists = context.machineState.memory.getAs<Uint8>(existsOffset);
+      expect(exists).toEqual(new Uint8(0));
+
+      const journalState = context.persistableState.flush();
+      expect(journalState.l1ToL2MessageChecks).toEqual([
+        expect.objectContaining({ leafIndex: leafIndex.toFr(), msgHash: msgHash.toFr(), exists: false }),
+      ]);
+    });
   });
 
   describe('EmitUnencryptedLog', () => {

yarn-project/simulator/src/public/db.ts

@@ -92,6 +92,12 @@ export interface CommitmentsDB {
     secret: Fr,
   ): Promise<MessageLoadOracleInputs<typeof L1_TO_L2_MSG_TREE_HEIGHT>>;
 
+  /**
+   * @param leafIndex the leaf to look up
+   * @returns The l1 to l2 leaf value or undefined if not found.
+   */
+  getL1ToL2LeafValue(leafIndex: bigint): Promise<Fr | undefined>;
+
   /**
    * Gets the index of a commitment in the note hash tree.
    * @param commitment - The commitment.

yarn-project/simulator/src/public/public_executor.ts

@@ -257,6 +257,10 @@ export class WorldStateDB implements CommitmentsDB {
     return new MessageLoadOracleInputs<typeof L1_TO_L2_MSG_TREE_HEIGHT>(messageIndex, siblingPath);
   }
 
+  public async getL1ToL2LeafValue(leafIndex: bigint): Promise<Fr | undefined> {
+    return await this.db.getLeafValue(MerkleTreeId.L1_TO_L2_MESSAGE_TREE, leafIndex);
+  }
+
   public async getCommitmentIndex(commitment: Fr): Promise<bigint | undefined> {
     return await this.db.findLeafIndex(MerkleTreeId.NOTE_HASH_TREE, commitment);
   }