fix for fast sync regression on post-merge networks (#4224)

* use attached/detached rule difference to prevent PoW rules from influencing fast sync around TTD

Signed-off-by: garyschulte <garyschulte@gmail.com>

ethereum/core/src/main/java/org/hyperledger/besu/ethereum/mainnet/MainnetBlockHeaderValidator.java

@@ -14,9 +14,11 @@
  */
 package org.hyperledger.besu.ethereum.mainnet;
 
+import org.hyperledger.besu.config.MergeConfigOptions;
 import org.hyperledger.besu.ethereum.core.BlockHeader;
 import org.hyperledger.besu.ethereum.mainnet.feemarket.BaseFeeMarket;
 import org.hyperledger.besu.ethereum.mainnet.headervalidationrules.AncestryValidationRule;
+import org.hyperledger.besu.ethereum.mainnet.headervalidationrules.AttachedProofOfWorkValidationRule;
 import org.hyperledger.besu.ethereum.mainnet.headervalidationrules.BaseFeeMarketBlockHeaderGasPriceValidationRule;
 import org.hyperledger.besu.ethereum.mainnet.headervalidationrules.CalculatedDifficultyValidationRule;
 import org.hyperledger.besu.ethereum.mainnet.headervalidationrules.ConstantFieldValidationRule;
@@ -122,22 +124,35 @@ public final class MainnetBlockHeaderValidator {
 
   public static BlockHeaderValidator.Builder createBaseFeeMarketValidator(
       final BaseFeeMarket baseFeeMarket) {
-    return new BlockHeaderValidator.Builder()
-        .addRule(CalculatedDifficultyValidationRule::new)
-        .addRule(new AncestryValidationRule())
-        .addRule(new GasUsageValidationRule())
-        .addRule(
-            new GasLimitRangeAndDeltaValidationRule(
-                MIN_GAS_LIMIT, Long.MAX_VALUE, Optional.of(baseFeeMarket)))
-        .addRule(new TimestampMoreRecentThanParent(MINIMUM_SECONDS_SINCE_PARENT))
-        .addRule(new TimestampBoundedByFutureParameter(TIMESTAMP_TOLERANCE_S))
-        .addRule(new ExtraDataMaxLengthValidationRule(BlockHeader.MAX_EXTRA_DATA_BYTES))
-        .addRule(
-            new ProofOfWorkValidationRule(
-                new EpochCalculator.DefaultEpochCalculator(),
-                PoWHasher.ETHASH_LIGHT,
-                Optional.of(baseFeeMarket)))
-        .addRule((new BaseFeeMarketBlockHeaderGasPriceValidationRule(baseFeeMarket)));
+    var builder =
+        new BlockHeaderValidator.Builder()
+            .addRule(CalculatedDifficultyValidationRule::new)
+            .addRule(new AncestryValidationRule())
+            .addRule(new GasUsageValidationRule())
+            .addRule(
+                new GasLimitRangeAndDeltaValidationRule(
+                    MIN_GAS_LIMIT, Long.MAX_VALUE, Optional.of(baseFeeMarket)))
+            .addRule(new TimestampMoreRecentThanParent(MINIMUM_SECONDS_SINCE_PARENT))
+            .addRule(new TimestampBoundedByFutureParameter(TIMESTAMP_TOLERANCE_S))
+            .addRule(new ExtraDataMaxLengthValidationRule(BlockHeader.MAX_EXTRA_DATA_BYTES))
+            .addRule((new BaseFeeMarketBlockHeaderGasPriceValidationRule(baseFeeMarket)));
+
+    // if merge is enabled, use the attached version of the proof of work validation rule
+    if (MergeConfigOptions.isMergeEnabled()) {
+      builder.addRule(
+          new AttachedProofOfWorkValidationRule(
+              new EpochCalculator.DefaultEpochCalculator(),
+              PoWHasher.ETHASH_LIGHT,
+              Optional.of(baseFeeMarket)));
+
+    } else {
+      builder.addRule(
+          new ProofOfWorkValidationRule(
+              new EpochCalculator.DefaultEpochCalculator(),
+              PoWHasher.ETHASH_LIGHT,
+              Optional.of(baseFeeMarket)));
+    }
+    return builder;
   }
 
   static BlockHeaderValidator.Builder createBaseFeeMarketOmmerValidator(

ethereum/core/src/main/java/org/hyperledger/besu/ethereum/mainnet/headervalidationrules/AttachedProofOfWorkValidationRule.java

@@ -0,0 +1,46 @@
+/*
+ * Copyright Hyperledger Besu Contributors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with
+ * the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on
+ * an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the
+ * specific language governing permissions and limitations under the License.
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+package org.hyperledger.besu.ethereum.mainnet.headervalidationrules;
+
+import org.hyperledger.besu.ethereum.ProtocolContext;
+import org.hyperledger.besu.ethereum.core.BlockHeader;
+import org.hyperledger.besu.ethereum.mainnet.AttachedBlockHeaderValidationRule;
+import org.hyperledger.besu.ethereum.mainnet.EpochCalculator;
+import org.hyperledger.besu.ethereum.mainnet.PoWHasher;
+import org.hyperledger.besu.ethereum.mainnet.feemarket.FeeMarket;
+
+import java.util.Optional;
+
+/**
+ * An attached proof of work validation rule that wraps the detached version of the same. Suitable
+ * for use in block validator stacks supporting the merge.
+ */
+public class AttachedProofOfWorkValidationRule implements AttachedBlockHeaderValidationRule {
+
+  private final ProofOfWorkValidationRule detachedRule;
+
+  public AttachedProofOfWorkValidationRule(
+      final EpochCalculator epochCalculator,
+      final PoWHasher hasher,
+      final Optional<FeeMarket> feeMarket) {
+    this.detachedRule = new ProofOfWorkValidationRule(epochCalculator, hasher, feeMarket);
+  }
+
+  @Override
+  public boolean validate(
+      final BlockHeader header, final BlockHeader parent, final ProtocolContext protocolContext) {
+    return detachedRule.validate(header, parent);
+  }
+}

ethereum/core/src/main/java/org/hyperledger/besu/ethereum/mainnet/headervalidationrules/CalculatedDifficultyValidationRule.java

@@ -14,7 +14,6 @@
  */
 package org.hyperledger.besu.ethereum.mainnet.headervalidationrules;
 
-import org.hyperledger.besu.config.MergeConfigOptions;
 import org.hyperledger.besu.ethereum.ProtocolContext;
 import org.hyperledger.besu.ethereum.core.BlockHeader;
 import org.hyperledger.besu.ethereum.mainnet.AttachedBlockHeaderValidationRule;
@@ -37,9 +36,7 @@ public class CalculatedDifficultyValidationRule implements AttachedBlockHeaderVa
   @Override
   public boolean validate(
       final BlockHeader header, final BlockHeader parent, final ProtocolContext context) {
-    if (MergeConfigOptions.isMergeEnabled()) {
-      return true;
-    }
+
     final BigInteger actualDifficulty = new BigInteger(1, header.getDifficulty().toArray());
     final BigInteger expectedDifficulty =
         difficultyCalculator.nextDifficulty(header.getTimestamp(), parent, context);

ethereum/core/src/main/java/org/hyperledger/besu/ethereum/mainnet/headervalidationrules/ProofOfWorkValidationRule.java

@@ -16,7 +16,6 @@ package org.hyperledger.besu.ethereum.mainnet.headervalidationrules;
 
 import static java.lang.Boolean.FALSE;
 
-import org.hyperledger.besu.config.MergeConfigOptions;
 import org.hyperledger.besu.datatypes.Hash;
 import org.hyperledger.besu.ethereum.core.BlockHeader;
 import org.hyperledger.besu.ethereum.mainnet.DetachedBlockHeaderValidationRule;
@@ -70,12 +69,6 @@ public final class ProofOfWorkValidationRule implements DetachedBlockHeaderValid
       return false;
     }
 
-    // TODO: remove this rule bypass, use post-merge headervalidation rules
-    // https://github.com/hyperledger/besu/issues/2898
-    if (MergeConfigOptions.isMergeEnabled()) {
-      return true;
-    }
-
     final Hash headerHash = hashHeader(header);
     PoWSolution solution =
         hasher.hash(header.getNonce(), header.getNumber(), epochCalculator, headerHash);

ethereum/core/src/main/java/org/hyperledger/besu/ethereum/mainnet/headervalidationrules/TimestampMoreRecentThanParent.java

@@ -16,7 +16,6 @@ package org.hyperledger.besu.ethereum.mainnet.headervalidationrules;
 
 import static com.google.common.base.Preconditions.checkArgument;
 
-import org.hyperledger.besu.config.MergeConfigOptions;
 import org.hyperledger.besu.ethereum.core.BlockHeader;
 import org.hyperledger.besu.ethereum.mainnet.DetachedBlockHeaderValidationRule;
 
@@ -36,9 +35,6 @@ public class TimestampMoreRecentThanParent implements DetachedBlockHeaderValidat
 
   @Override
   public boolean validate(final BlockHeader header, final BlockHeader parent) {
-    if (MergeConfigOptions.isMergeEnabled()) {
-      return true;
-    }
     return validateTimestamp(header.getTimestamp(), parent.getTimestamp());
   }