init

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

@@ -63,11 +63,12 @@ import { createProverClient } from '@aztec/prover-client';
 import {
   AggregateTxValidator,
   DataTxValidator,
+  DoubleSpendTxValidator,
   type GlobalVariableBuilder,
   SequencerClient,
   getGlobalVariableBuilder,
 } from '@aztec/sequencer-client';
-import { PublicProcessorFactory, WASMSimulator, createSimulationProvider } from '@aztec/simulator';
+import { PublicProcessorFactory, WASMSimulator, WorldStateDB, createSimulationProvider } from '@aztec/simulator';
 import { type TelemetryClient } from '@aztec/telemetry-client';
 import { NoopTelemetryClient } from '@aztec/telemetry-client/noop';
 import {
@@ -165,6 +166,7 @@ export class AztecNodeService implements AztecNode {
       new DataTxValidator(),
       new MetadataTxValidator(config.l1ChainId),
       new TxProofValidator(proofVerifier),
+      new DoubleSpendTxValidator(new WorldStateDB(worldStateSynchronizer.getLatest())),
     );
 
     const simulationProvider = await createSimulationProvider(config, log);
@@ -339,9 +341,7 @@ export class AztecNodeService implements AztecNode {
     const timer = new Timer();
     this.log.info(`Received tx ${tx.getTxHash()}`);
 
-    const [_, invalidTxs] = await this.txValidator.validateTxs([tx]);
-    if (invalidTxs.length > 0) {
-      this.log.warn(`Rejecting tx ${tx.getTxHash()} because of validation errors`);
+    if ((await this.validateTx(tx)) === false) {
       this.metrics.receivedTx(timer.ms(), false);
       return;
     }
@@ -768,6 +768,17 @@ export class AztecNodeService implements AztecNode {
     );
   }
 
+  public async validateTx(tx: Tx): Promise<boolean> {
+    const [_, invalidTxs] = await this.txValidator.validateTxs([tx]);
+    if (invalidTxs.length > 0) {
+      this.log.warn(`Rejecting tx ${tx.getTxHash()} because of validation errors`);
+
+      return false;
+    }
+
+    return true;
+  }
+
   public async setConfig(config: Partial<SequencerConfig & ProverConfig>): Promise<void> {
     const newConfig = { ...this.config, ...config };
     this.sequencer?.updateSequencerConfig(config);

yarn-project/circuit-types/src/interfaces/aztec-node.ts

@@ -316,6 +316,13 @@ export interface AztecNode {
    **/
   simulatePublicCalls(tx: Tx): Promise<PublicSimulationOutput>;
 
+  /**
+   * Validates the correctness of the execution, namely that a transaction is valid if and
+   * only if the transaction can be added to a valid block at the current state.
+   * @param tx - The transaction to validate for correctness.
+   */
+  validateTx(tx: Tx): Promise<boolean>;
+
   /**
    * Updates the configuration of this node.
    * @param config - Updated configuration to be merged with the current one.

yarn-project/pxe/src/pxe_service/pxe_service.ts

@@ -498,13 +498,22 @@ export class PXEService implements PXE {
     simulatePublic: boolean,
     msgSender: AztecAddress | undefined = undefined,
     scopes?: AztecAddress[],
+    offline: boolean = false,
   ): Promise<SimulatedTx> {
     return await this.jobQueue.put(async () => {
       const simulatedTx = await this.#simulateAndProve(txRequest, this.fakeProofCreator, msgSender, scopes);
       if (simulatePublic) {
         simulatedTx.publicOutput = await this.#simulatePublicCalls(simulatedTx.tx);
       }
 
+      if (!offline) {
+        const isValidTx = await this.node.validateTx(simulatedTx.tx);
+
+        if (!isValidTx) {
+          throw new Error('The simulated transaction is unable to be added to state and is invalid.');
+        }
+      }
+
       // We log only if the msgSender is undefined, as simulating with a different msgSender
       // is unlikely to be a real transaction, and likely to be only used to read data.
       // Meaning that it will not necessarily have produced a nullifier (and thus have no TxHash)

yarn-project/sequencer-client/src/index.ts

@@ -4,6 +4,7 @@ export * from './publisher/index.js';
 export * from './sequencer/index.js';
 export * from './tx_validator/aggregate_tx_validator.js';
 export * from './tx_validator/data_validator.js';
+export * from './tx_validator/double_spend_validator.js';
 
 // Used by the node to simulate public parts of transactions. Should these be moved to a shared library?
 export * from './global_variable_builder/index.js';