Added config items for late block reorg

 - added  `REORG_HEAD_WEIGHT_THRESHOLD`, `REORG_PARENT_WEIGHT_THRESHOLD`, and  `REORG_MAX_EPOCHS_SINCE_FINALIZATION` to phase0 configuration, and defaulted

 - added utility functions:
   - `isShufflingStable`
   - `isFinalizationOk`
   - `calculateCommitteeFraction`

which were part of the changes in ethereum/consensus-specs#3034

partially addresses Consensys#6595

Signed-off-by: Paul Harris <[email protected]>

CHANGELOG.md

@@ -13,5 +13,6 @@ the [releases page](https://github.com/Consensys/teku/releases).
 - By default, Teku won't allow syncing from genesis, users should use `--checkpoint-sync-url` when starting a new node. It is possible to revert back to the previous behaviour using the flag `--ignore-weak-subjectivity-period-enabled`.
 
 ### Additions and Improvements
+- Added configuration attributes in support of honest validator late block reorg, which adds `REORG_HEAD_WEIGHT_THRESHOLD`, `REORG_PARENT_WEIGHT_THRESHOLD`, and  `REORG_MAX_EPOCHS_SINCE_FINALIZATION` to phase 0 configurations. Mainnet values have been added as defaults for configurations that have not explicitly listed them.
 
 ### Bug Fixes

ethereum/spec/src/main/java/tech/pegasys/teku/spec/config/DelegatingSpecConfig.java

@@ -281,6 +281,21 @@ public int getSafeSlotsToUpdateJustified() {
     return specConfig.getSafeSlotsToUpdateJustified();
   }
 
+  @Override
+  public int getReorgMaxEpochsSinceFinalization() {
+    return specConfig.getReorgMaxEpochsSinceFinalization();
+  }
+
+  @Override
+  public int getReorgHeadWeightThreshold() {
+    return specConfig.getReorgHeadWeightThreshold();
+  }
+
+  @Override
+  public int getReorgParentWeightThreshold() {
+    return specConfig.getReorgParentWeightThreshold();
+  }
+
   @Override
   public long getDepositChainId() {
     return specConfig.getDepositChainId();

ethereum/spec/src/main/java/tech/pegasys/teku/spec/config/SpecConfig.java

@@ -160,6 +160,12 @@ default int getMillisPerSlot() {
   // Misc
   int getSafeSlotsToUpdateJustified();
 
+  int getReorgMaxEpochsSinceFinalization();
+
+  int getReorgHeadWeightThreshold();
+
+  int getReorgParentWeightThreshold();
+
   // Casters
   default Optional<SpecConfigAltair> toVersionAltair() {
     return Optional.empty();

ethereum/spec/src/main/java/tech/pegasys/teku/spec/config/SpecConfigPhase0.java

@@ -116,6 +116,10 @@ public class SpecConfigPhase0 implements SpecConfig {
   private final int attestationSubnetCount;
   private final int attestationSubnetExtraBits;
   private final int attestationSubnetPrefixBits;
+  private final int reorgMaxEpochsSinceFinalization;
+
+  private final int reorgHeadWeightThreshold;
+  private final int reorgParentWeightThreshold;
 
   public SpecConfigPhase0(
       final Map<String, Object> rawConfig,
@@ -182,7 +186,10 @@ public SpecConfigPhase0(
       final int subnetsPerNode,
       final int attestationSubnetCount,
       final int attestationSubnetExtraBits,
-      final int attestationSubnetPrefixBits) {
+      final int attestationSubnetPrefixBits,
+      final int reorgMaxEpochsSinceFinalization,
+      final int reorgHeadWeightThreshold,
+      final int reorgParentWeightThreshold) {
     this.rawConfig = rawConfig;
     this.eth1FollowDistance = eth1FollowDistance;
     this.maxCommitteesPerSlot = maxCommitteesPerSlot;
@@ -249,6 +256,9 @@ public SpecConfigPhase0(
     this.attestationSubnetCount = attestationSubnetCount;
     this.attestationSubnetExtraBits = attestationSubnetExtraBits;
     this.attestationSubnetPrefixBits = attestationSubnetPrefixBits;
+    this.reorgMaxEpochsSinceFinalization = reorgMaxEpochsSinceFinalization;
+    this.reorgHeadWeightThreshold = reorgHeadWeightThreshold;
+    this.reorgParentWeightThreshold = reorgParentWeightThreshold;
   }
 
   @Override
@@ -506,6 +516,21 @@ public int getSafeSlotsToUpdateJustified() {
     return safeSlotsToUpdateJustified;
   }
 
+  @Override
+  public int getReorgMaxEpochsSinceFinalization() {
+    return reorgMaxEpochsSinceFinalization;
+  }
+
+  @Override
+  public int getReorgHeadWeightThreshold() {
+    return reorgHeadWeightThreshold;
+  }
+
+  @Override
+  public int getReorgParentWeightThreshold() {
+    return reorgParentWeightThreshold;
+  }
+
   @Override
   public int getProposerScoreBoost() {
     return proposerScoreBoost;

ethereum/spec/src/main/java/tech/pegasys/teku/spec/config/builder/SpecConfigBuilder.java

@@ -123,6 +123,13 @@ public class SpecConfigBuilder {
   private Integer attestationSubnetExtraBits;
   private Integer attestationSubnetPrefixBits;
 
+  // added after Phase0, so add default values, or will be compatability issue
+  private Integer reorgMaxEpochsSinceFinalization = 2;
+
+  private Integer reorgHeadWeightThreshold = 20;
+
+  private Integer reorgParentWeightThreshold = 160;
+
   private final BuilderChain<SpecConfig, SpecConfigDeneb> builderChain =
       BuilderChain.create(new AltairBuilder())
           .appendBuilder(new BellatrixBuilder())
@@ -203,7 +210,10 @@ public SpecConfig build() {
             subnetsPerNode,
             attestationSubnetCount,
             attestationSubnetExtraBits,
-            attestationSubnetPrefixBits);
+            attestationSubnetPrefixBits,
+            reorgMaxEpochsSinceFinalization,
+            reorgHeadWeightThreshold,
+            reorgParentWeightThreshold);
 
     return builderChain.build(config);
   }
@@ -274,6 +284,9 @@ private Map<String, Object> getValidationMap() {
     constants.put("attestationSubnetCount", attestationSubnetCount);
     constants.put("attestationSubnetExtraBits", attestationSubnetExtraBits);
     constants.put("attestationSubnetPrefixBits", attestationSubnetPrefixBits);
+    constants.put("reorgMaxEpochsSinceFinalization", reorgMaxEpochsSinceFinalization);
+    constants.put("reorgHeadWeightThreshold", reorgHeadWeightThreshold);
+    constants.put("reorgParentWeightThreshold", reorgParentWeightThreshold);
     return constants;
   }
 
@@ -677,6 +690,22 @@ public SpecConfigBuilder attestationSubnetPrefixBits(final Integer attestationSu
     return this;
   }
 
+  public SpecConfigBuilder reorgMaxEpochsSinceFinalization(
+      final Integer reorgMaxEpochsSinceFinalization) {
+    this.reorgMaxEpochsSinceFinalization = reorgMaxEpochsSinceFinalization;
+    return this;
+  }
+
+  public SpecConfigBuilder reorgHeadWeightThreshold(final Integer reorgHeadWeightThreshold) {
+    this.reorgHeadWeightThreshold = reorgHeadWeightThreshold;
+    return this;
+  }
+
+  public SpecConfigBuilder reorgParentWeightThreshold(final Integer reorgParentWeightThreshold) {
+    this.reorgParentWeightThreshold = reorgParentWeightThreshold;
+    return this;
+  }
+
   public SpecConfigBuilder altairBuilder(final Consumer<AltairBuilder> consumer) {
     builderChain.withBuilder(AltairBuilder.class, consumer);
     return this;

ethereum/spec/src/main/java/tech/pegasys/teku/spec/logic/common/helpers/BeaconStateAccessors.java

@@ -162,6 +162,20 @@ public Bytes32 getSeed(BeaconState state, UInt64 epoch, Bytes4 domainType)
     return Hash.sha256(domainType.getWrappedBytes(), epochBytes, mix);
   }
 
+  /**
+   * calculate_committee_fraction Refer to fork-choice specification.
+   *
+   * @param beaconState
+   * @param committeePercent
+   * @return
+   */
+  public UInt64 calculateCommitteeFraction(
+      final BeaconState beaconState, final UInt64 committeePercent) {
+    final UInt64 committeeWeight =
+        getTotalActiveBalance(beaconState).dividedBy(config.getSlotsPerEpoch());
+    return committeeWeight.times(committeePercent).dividedBy(100);
+  }
+
   /**
    * return the number of committees in each slot for the given `epoch`.
    *

ethereum/spec/src/main/java/tech/pegasys/teku/spec/logic/common/util/ForkChoiceUtil.java

@@ -167,6 +167,27 @@ public NavigableMap<UInt64, Bytes32> getAncestorsOnFork(
     return roots;
   }
 
+  /**
+   * is_shuffling_stable
+   *
+   * <p>Refer to fork-choice specification.
+   *
+   * @param slot
+   * @return
+   */
+  public boolean isShufflingStable(final UInt64 slot) {
+    return !slot.mod(specConfig.getSlotsPerEpoch()).isZero();
+  }
+
+  public boolean isFinalizationOk(final ReadOnlyStore store, final UInt64 slot) {
+    final UInt64 epochsSinceFinalization =
+        miscHelpers
+            .computeEpochAtSlot(slot)
+            .minusMinZero(store.getFinalizedCheckpoint().getEpoch());
+    return epochsSinceFinalization.isLessThanOrEqualTo(
+        specConfig.getReorgMaxEpochsSinceFinalization());
+  }
+
   private void maybeAddRoot(
       final UInt64 startSlot,
       final UInt64 step,

ethereum/spec/src/main/resources/tech/pegasys/teku/spec/config/configs/chiado.yaml

@@ -43,6 +43,12 @@ HYSTERESIS_UPWARD_MULTIPLIER: 5
 # ---------------------------------------------------------------
 # 2**3 (= 8)
 SAFE_SLOTS_TO_UPDATE_JUSTIFIED: 8
+# 20%
+REORG_HEAD_WEIGHT_THRESHOLD: 20
+# 160%
+REORG_PARENT_WEIGHT_THRESHOLD: 160
+# `2` epochs
+REORG_MAX_EPOCHS_SINCE_FINALIZATION: 2
 # Validator
 # ---------------------------------------------------------------
 # 2**10 (= 1024) ~1.4 hour

ethereum/spec/src/main/resources/tech/pegasys/teku/spec/config/configs/gnosis.yaml

@@ -76,7 +76,12 @@ CHURN_LIMIT_QUOTIENT: 4096
 # ---------------------------------------------------------------
 # 40%
 PROPOSER_SCORE_BOOST: 40
-
+# 20%
+REORG_HEAD_WEIGHT_THRESHOLD: 20
+# 160%
+REORG_PARENT_WEIGHT_THRESHOLD: 160
+# `2` epochs
+REORG_MAX_EPOCHS_SINCE_FINALIZATION: 2
 
 # Deposit contract
 # ---------------------------------------------------------------

ethereum/spec/src/main/resources/tech/pegasys/teku/spec/config/configs/holesky.yaml

@@ -66,6 +66,12 @@ MAX_PER_EPOCH_ACTIVATION_CHURN_LIMIT: 8
 # ---------------------------------------------------------------
 # 40%
 PROPOSER_SCORE_BOOST: 40
+# 20%
+REORG_HEAD_WEIGHT_THRESHOLD: 20
+# 160%
+REORG_PARENT_WEIGHT_THRESHOLD: 160
+# `2` epochs
+REORG_MAX_EPOCHS_SINCE_FINALIZATION: 2
 
 # Deposit contract
 # ---------------------------------------------------------------

ethereum/spec/src/main/resources/tech/pegasys/teku/spec/config/configs/less-swift.yaml

@@ -79,6 +79,12 @@ CHURN_LIMIT_QUOTIENT: 32
 # ---------------------------------------------------------------
 # 70%
 PROPOSER_SCORE_BOOST: 70
+# 20%
+REORG_HEAD_WEIGHT_THRESHOLD: 20
+# 160%
+REORG_PARENT_WEIGHT_THRESHOLD: 160
+# `2` epochs
+REORG_MAX_EPOCHS_SINCE_FINALIZATION: 2
 
 
 # Deposit contract

ethereum/spec/src/main/resources/tech/pegasys/teku/spec/config/configs/lukso.yaml

@@ -63,6 +63,12 @@ CAPELLA_FORK_EPOCH: 8100
 # ---------------------------------------------------------------
 # 40%
 PROPOSER_SCORE_BOOST: 40
+# 20%
+REORG_HEAD_WEIGHT_THRESHOLD: 20
+# 160%
+REORG_PARENT_WEIGHT_THRESHOLD: 160
+# `2` epochs
+REORG_MAX_EPOCHS_SINCE_FINALIZATION: 2
 
 # Time parameters
 # ---------------------------------------------------------------

ethereum/spec/src/main/resources/tech/pegasys/teku/spec/config/configs/mainnet.yaml

@@ -92,6 +92,12 @@ MAX_PER_EPOCH_ACTIVATION_CHURN_LIMIT: 8
 # ---------------------------------------------------------------
 # 40%
 PROPOSER_SCORE_BOOST: 40
+# 20%
+REORG_HEAD_WEIGHT_THRESHOLD: 20
+# 160%
+REORG_PARENT_WEIGHT_THRESHOLD: 160
+# `2` epochs
+REORG_MAX_EPOCHS_SINCE_FINALIZATION: 2
 
 # Deposit contract
 # ---------------------------------------------------------------

ethereum/spec/src/main/resources/tech/pegasys/teku/spec/config/configs/minimal.yaml

@@ -91,7 +91,12 @@ MAX_PER_EPOCH_ACTIVATION_CHURN_LIMIT: 4
 # ---------------------------------------------------------------
 # 40%
 PROPOSER_SCORE_BOOST: 40
-
+# 20%
+REORG_HEAD_WEIGHT_THRESHOLD: 20
+# 160%
+REORG_PARENT_WEIGHT_THRESHOLD: 160
+# `2` epochs
+REORG_MAX_EPOCHS_SINCE_FINALIZATION: 2
 
 # Deposit contract
 # ---------------------------------------------------------------

ethereum/spec/src/main/resources/tech/pegasys/teku/spec/config/configs/prater.yaml

@@ -77,7 +77,12 @@ CHURN_LIMIT_QUOTIENT: 65536
 # ---------------------------------------------------------------
 # 70%
 PROPOSER_SCORE_BOOST: 70
-
+# 20%
+REORG_HEAD_WEIGHT_THRESHOLD: 20
+# 160%
+REORG_PARENT_WEIGHT_THRESHOLD: 160
+# `2` epochs
+REORG_MAX_EPOCHS_SINCE_FINALIZATION: 2
 
 # Deposit contract
 # ---------------------------------------------------------------

ethereum/spec/src/main/resources/tech/pegasys/teku/spec/config/configs/sepolia.yaml

@@ -68,6 +68,12 @@ CHURN_LIMIT_QUOTIENT: 65536
 # ---------------------------------------------------------------
 # 40%
 PROPOSER_SCORE_BOOST: 40
+# 20%
+REORG_HEAD_WEIGHT_THRESHOLD: 20
+# 160%
+REORG_PARENT_WEIGHT_THRESHOLD: 160
+# `2` epochs
+REORG_MAX_EPOCHS_SINCE_FINALIZATION: 2
 
 # Deposit contract
 # ---------------------------------------------------------------

ethereum/spec/src/main/resources/tech/pegasys/teku/spec/config/configs/swift.yaml

@@ -80,6 +80,12 @@ MAX_PER_EPOCH_ACTIVATION_CHURN_LIMIT: 8
 # ---------------------------------------------------------------
 # 70%
 PROPOSER_SCORE_BOOST: 70
+# 20%
+REORG_HEAD_WEIGHT_THRESHOLD: 20
+# 160%
+REORG_PARENT_WEIGHT_THRESHOLD: 160
+# `2` epochs
+REORG_MAX_EPOCHS_SINCE_FINALIZATION: 2
 
 
 # Deposit contract

ethereum/spec/src/test/java/tech/pegasys/teku/spec/logic/common/helpers/BeaconStateAccessorsTest.java

@@ -13,6 +13,7 @@
 
 package tech.pegasys.teku.spec.logic.common.helpers;
 
+import static org.assertj.core.api.Assertions.assertThat;
 import static org.assertj.core.api.AssertionsForClassTypes.assertThatThrownBy;
 import static org.junit.jupiter.api.Assertions.assertDoesNotThrow;
 import static org.junit.jupiter.api.Assertions.assertEquals;
@@ -129,6 +130,32 @@ public void getBeaconCommittee_stateIsNewerThanSlot() {
     assertDoesNotThrow(() -> beaconStateAccessors.getBeaconCommittee(state, oldSlot, ONE));
   }
 
+  @Test
+  void calculateCommitteeFraction_full() {
+    final BeaconState state = dataStructureUtil.randomBeaconState(1024);
+    final UInt64 totalActiveBalance =
+        spec.atSlot(state.getSlot()).beaconStateAccessors().getTotalActiveBalance(state);
+    final UInt64 totalActiveBalancePerSlot =
+        totalActiveBalance.dividedBy(spec.getGenesisSpec().getSlotsPerEpoch());
+    final UInt64 fraction =
+        beaconStateAccessors.calculateCommitteeFraction(state, UInt64.valueOf(100));
+    // at its simplest, if we've divided by slots in the function, this should be
+    // totalActiveBalance/slots (because fraction is 100%)
+    assertThat(fraction).isEqualTo(totalActiveBalancePerSlot);
+  }
+
+  @Test
+  void calculateCommitteeFraction_minimal() {
+    final BeaconState state = dataStructureUtil.randomBeaconState(1024);
+    final UInt64 totalActiveBalance =
+        spec.atSlot(state.getSlot()).beaconStateAccessors().getTotalActiveBalance(state);
+    final UInt64 totalActiveBalancePerSlot =
+        totalActiveBalance.dividedBy(spec.getGenesisSpec().getSlotsPerEpoch());
+    final UInt64 fraction = beaconStateAccessors.calculateCommitteeFraction(state, UInt64.ONE);
+    // should be 1% of balance per slot...
+    assertThat(fraction).isEqualTo(totalActiveBalancePerSlot.dividedBy(100));
+  }
+
   private BeaconState createBeaconState() {
     return new BeaconStateTestBuilder(dataStructureUtil)
         .forkVersion(specConfig.getGenesisForkVersion())