fix: use anchor block on getL1ToL2MsgWitness (#21872)

I made the param be optional in the fn since it has other unrelated
callsites (e.g. the CLI). I also merged both node roundtrips into a
single one.

Author: nventuro

yarn-project/pxe/src/contract_function_simulator/oracle/utility_execution_oracle.ts

@@ -380,7 +380,7 @@ export class UtilityExecutionOracle implements IMiscOracle, IUtilityExecutionOra
   }
 
   /**
-   * Fetches a message from the executionStore, given its key.
+   * Returns the membership witness of an un-nullified L1 to L2 message.
    * @param contractAddress - Address of a contract by which the message was emitted.
    * @param messageHash - Hash of the message.
    * @param secret - Secret used to compute a nullifier.
@@ -393,6 +393,7 @@ export class UtilityExecutionOracle implements IMiscOracle, IUtilityExecutionOra
       contractAddress,
       messageHash,
       secret,
+      await this.anchorBlockHeader.hash(),
     );
 
     return new MessageLoadOracleInputs(messageIndex, siblingPath);

yarn-project/stdlib/src/messaging/l1_to_l2_message.ts

@@ -6,6 +6,7 @@ import { bufferToHex } from '@aztec/foundation/string';
 import { SiblingPath } from '@aztec/foundation/trees';
 
 import type { AztecAddress } from '../aztec-address/index.js';
+import type { BlockParameter } from '../block/block_parameter.js';
 import { computeL1ToL2MessageNullifier } from '../hash/hash.js';
 import type { AztecNode } from '../interfaces/aztec-node.js';
 import { MerkleTreeId } from '../trees/merkle_tree_id.js';
@@ -79,20 +80,22 @@ export async function getNonNullifiedL1ToL2MessageWitness(
   contractAddress: AztecAddress,
   messageHash: Fr,
   secret: Fr,
+  referenceBlock: BlockParameter = 'latest',
 ): Promise<[bigint, SiblingPath<typeof L1_TO_L2_MSG_TREE_HEIGHT>]> {
-  const response = await node.getL1ToL2MessageMembershipWitness('latest', messageHash);
-  if (!response) {
-    throw new Error(`No L1 to L2 message found for message hash ${messageHash.toString()}`);
-  }
+  const messageNullifier = await computeL1ToL2MessageNullifier(contractAddress, messageHash, secret);
 
-  const [messageIndex, siblingPath] = response;
+  const [l1ToL2Response, nullifierResponse] = await Promise.all([
+    node.getL1ToL2MessageMembershipWitness(referenceBlock, messageHash),
+    node.findLeavesIndexes(referenceBlock, MerkleTreeId.NULLIFIER_TREE, [messageNullifier]),
+  ]);
 
-  const messageNullifier = await computeL1ToL2MessageNullifier(contractAddress, messageHash, secret);
+  if (!l1ToL2Response) {
+    throw new Error(`No L1 to L2 message found for message hash ${messageHash.toString()}`);
+  }
 
-  const [nullifierIndex] = await node.findLeavesIndexes('latest', MerkleTreeId.NULLIFIER_TREE, [messageNullifier]);
-  if (nullifierIndex !== undefined) {
+  if (nullifierResponse[0] !== undefined) {
     throw new Error(`No non-nullified L1 to L2 message found for message hash ${messageHash.toString()}`);
   }
 
-  return [messageIndex, siblingPath];
+  return l1ToL2Response;
 }