Allow frontier simulation when Base Fee is present

ethereum/api/src/integration-test/java/org/hyperledger/besu/ethereum/api/jsonrpc/methods/fork/london/EthEstimateGasIntegrationTest.java

@@ -137,6 +137,7 @@ public void shouldReturnErrorWithInvalidChainId() {
             .withChainId(BLOCKCHAIN.getChainId().add(BigInteger.ONE))
             .withFrom(Address.fromHexString("0xa94f5374fce5edbc8e2a8697c15331677e6ebf0b"))
             .withTo(Address.fromHexString("0x8888f1f195afa192cfee860698584c030f4c9db1"))
+            .withMaxFeePerGas(Wei.ONE)
             .withValue(Wei.ONE)
             .build();
 

ethereum/core/src/main/java/org/hyperledger/besu/ethereum/transaction/TransactionSimulator.java

@@ -296,9 +296,6 @@ public Optional<TransactionSimulatorResult> processWithWorldUpdater(
     final long simulationGasCap =
         calculateSimulationGasCap(callParams.getGasLimit(), blockHeaderToProcess.getGasLimit());
 
-    final Wei value = callParams.getValue() != null ? callParams.getValue() : Wei.ZERO;
-    final Bytes payload = callParams.getPayload() != null ? callParams.getPayload() : Bytes.EMPTY;
-
     final MainnetTransactionProcessor transactionProcessor =
         protocolSchedule.getByBlockHeader(blockHeaderToProcess).getTransactionProcessor();
 
@@ -322,8 +319,6 @@ public Optional<TransactionSimulatorResult> processWithWorldUpdater(
             senderAddress,
             nonce,
             simulationGasCap,
-            value,
-            payload,
             blobGasPrice);
     if (maybeTransaction.isEmpty()) {
       return Optional.empty();
@@ -404,9 +399,11 @@ private Optional<Transaction> buildTransaction(
       final Address senderAddress,
       final long nonce,
       final long gasLimit,
-      final Wei value,
-      final Bytes payload,
       final Wei blobGasPrice) {
+
+    final Wei value = callParams.getValue() != null ? callParams.getValue() : Wei.ZERO;
+    final Bytes payload = callParams.getPayload() != null ? callParams.getPayload() : Bytes.EMPTY;
+
     final Transaction.Builder transactionBuilder =
         Transaction.builder()
             .nonce(nonce)
@@ -437,18 +434,21 @@ private Optional<Transaction> buildTransaction(
       maxPriorityFeePerGas = callParams.getMaxPriorityFeePerGas().orElse(gasPrice);
       maxFeePerBlobGas = callParams.getMaxFeePerBlobGas().orElse(blobGasPrice);
     }
-    if (header.getBaseFee().isEmpty()) {
+
+    if (shouldSetGasPrice(callParams, header)) {
       transactionBuilder.gasPrice(gasPrice);
-    } else if (protocolSchedule.getChainId().isPresent()) {
+    }
+
+    if (shouldSetMaxFeePerGas(callParams, header)) {
       transactionBuilder.maxFeePerGas(maxFeePerGas).maxPriorityFeePerGas(maxPriorityFeePerGas);
-    } else {
-      return Optional.empty();
     }
 
-    transactionBuilder.guessType();
-    if (transactionBuilder.getTransactionType().supportsBlob()) {
+    if (shouldSetBlobGasPrice(callParams)) {
       transactionBuilder.maxFeePerBlobGas(maxFeePerBlobGas);
     }
+
+    transactionBuilder.guessType();
+
     if (transactionBuilder.getTransactionType().requiresChainId()) {
       callParams
           .getChainId()
@@ -489,4 +489,39 @@ public Optional<Boolean> doesAddressExist(
 
     return Optional.of(worldState.get(address) != null);
   }
+
+  private boolean shouldSetGasPrice(final CallParameter callParams, final BlockHeader header) {
+    if (header.getBaseFee().isEmpty()) {
+      return true;
+    }
+
+    // if maxPriorityFeePerGas and maxFeePerGas are not set, use gasPrice
+    return callParams.getMaxPriorityFeePerGas().isEmpty() && callParams.getMaxFeePerGas().isEmpty();
+  }
+
+  private boolean shouldSetMaxFeePerGas(final CallParameter callParams, final BlockHeader header) {
+    if (protocolSchedule.getChainId().isEmpty()) {
+      return false;
+    }
+
+    if (header.getBaseFee().isEmpty()) {
+      return false;
+    }
+
+    if (shouldSetBlobGasPrice(callParams)) {
+      return true;
+    }
+
+    // only set maxFeePerGas and maxPriorityFeePerGas if they are present, otherwise transaction
+    // will be considered EIP-1559 transaction even if the simulation is for a legacy transaction
+    return callParams.getMaxPriorityFeePerGas().isPresent()
+        || callParams.getMaxFeePerGas().isPresent();
+  }
+
+  private boolean shouldSetBlobGasPrice(final CallParameter callParams) {
+    if (protocolSchedule.getChainId().isEmpty()) {
+      return false;
+    }
+    return callParams.getBlobVersionedHashes().isPresent();
+  }
 }

ethereum/core/src/test/java/org/hyperledger/besu/ethereum/transaction/TransactionSimulatorTest.java

@@ -912,4 +912,43 @@ private CallParameter blobTransactionCallParameter(
         Optional.of(maxFeePerBlobGas),
         Optional.of(bwc.getVersionedHashes()));
   }
+
+  @Test
+  public void shouldSimulateLegacyTransactionWhenBaseFeeNotZero() {
+    // tests that the transaction simulator will simulate a legacy transaction when the base fee is
+    // not zero
+    // and the transaction is a legacy transaction
+
+    final CallParameter callParameter = legacyTransactionCallParameter();
+
+    final BlockHeader blockHeader =
+        blockHeaderTestFixture
+            .number(1L)
+            .stateRoot(Hash.ZERO)
+            .baseFeePerGas(Wei.of(7))
+            .buildHeader();
+
+    mockBlockchainForBlockHeader(blockHeader);
+    mockWorldStateForAccount(blockHeader, callParameter.getFrom(), 1L);
+
+    final Transaction expectedTransaction =
+        Transaction.builder()
+            .type(TransactionType.FRONTIER)
+            .nonce(1L)
+            .gasPrice(callParameter.getGasPrice())
+            .gasLimit(blockHeader.getGasLimit())
+            .to(callParameter.getTo())
+            .sender(callParameter.getFrom())
+            .value(callParameter.getValue())
+            .payload(callParameter.getPayload())
+            .signature(FAKE_SIGNATURE)
+            .build();
+    mockProcessorStatusForTransaction(expectedTransaction, Status.SUCCESSFUL);
+
+    final Optional<TransactionSimulatorResult> result =
+        transactionSimulator.process(callParameter, 1L);
+
+    verifyTransactionWasProcessed(expectedTransaction);
+    assertThat(result.get().isSuccessful()).isTrue();
+  }
 }