feat!: Unencrypted logs are not strings

yarn-project/acir-simulator/src/acvm/oracle/oracle.ts

@@ -258,7 +258,7 @@ export class Oracle {
   }
 
   emitUnencryptedLog([contractAddress]: ACVMField[], [eventSelector]: ACVMField[], message: ACVMField[]): ACVMField {
-    const logPayload = Buffer.concat(message.map(charBuffer => Fr.fromString(charBuffer).toBuffer().subarray(-1)));
+    const logPayload = Buffer.concat(message.map(fromACVMField).map(f => f.toBuffer()));
     const log = new UnencryptedL2Log(
       AztecAddress.fromString(contractAddress),
       EventSelector.fromField(fromACVMField(eventSelector)),

yarn-project/acir-simulator/src/client/private_execution.test.ts

@@ -35,6 +35,7 @@ import {
 } from '@aztec/foundation/abi';
 import { asyncMap } from '@aztec/foundation/async-map';
 import { AztecAddress } from '@aztec/foundation/aztec-address';
+import { times } from '@aztec/foundation/collection';
 import { pedersenHash } from '@aztec/foundation/crypto';
 import { EthAddress } from '@aztec/foundation/eth-address';
 import { Fr, GrumpkinScalar } from '@aztec/foundation/fields';
@@ -60,6 +61,7 @@ import { KeyPair, MessageLoadOracleInputs } from '../acvm/index.js';
 import { buildL1ToL2Message } from '../test/utils.js';
 import { computeSlotForMapping } from '../utils.js';
 import { DBOracle } from './db_oracle.js';
+import { collectUnencryptedLogs } from './execution_result.js';
 import { AcirSimulator } from './simulator.js';
 
 jest.setTimeout(60_000);
@@ -232,6 +234,26 @@ describe('Private Execution test suite', () => {
       expect(sideEffectArrayToValueArray(result.callStackItem.publicInputs.newCommitments)).toEqual(emptyCommitments);
       expect(result.callStackItem.publicInputs.contractDeploymentData).toEqual(contractDeploymentData);
     });
+
+    it('emits a field as an unencrypted log', async () => {
+      const artifact = getFunctionArtifact(TestContractArtifact, 'emit_msg_sender');
+      const result = await runSimulator({ artifact, msgSender: owner });
+      const [functionLogs] = collectUnencryptedLogs(result);
+      expect(functionLogs.logs).toHaveLength(1);
+      // Test that the log payload (ie ignoring address, selector, and header) matches what we emitted
+      expect(functionLogs.logs[0].subarray(-32).toString('hex')).toEqual(owner.toBuffer().toString('hex'));
+    });
+
+    it('emits a field array as an unencrypted log', async () => {
+      const artifact = getFunctionArtifact(TestContractArtifact, 'emit_array_as_unencrypted_log');
+      const args = [times(5, () => Fr.random())];
+      const result = await runSimulator({ artifact, msgSender: owner, args });
+      const [functionLogs] = collectUnencryptedLogs(result);
+      expect(functionLogs.logs).toHaveLength(1);
+      // Test that the log payload (ie ignoring address, selector, and header) matches what we emitted
+      const expected = Buffer.concat(args[0].map(arg => arg.toBuffer())).toString('hex');
+      expect(functionLogs.logs[0].subarray(-32 * 5).toString('hex')).toEqual(expected);
+    });
   });
 
   describe('stateful test contract', () => {

yarn-project/noir-contracts/contracts/test_contract/src/main.nr

@@ -233,6 +233,11 @@ contract Test {
         emit_unencrypted_log_from_private(&mut context, context.msg_sender());
     }
 
+    #[aztec(private)]
+    fn emit_array_as_unencrypted_log(fields: [Field; 5]) {
+        emit_unencrypted_log_from_private(&mut context, fields);
+    }
+
     // docs:start:is-time-equal
     #[aztec(public)]
     fn is_time_equal(time: Field) -> Field {