Added more utilities for late block reorg (Consensys#7750)

* Added more utilities for late block reorg

 - is_parent_strong
 - is_head_weak
 - is_proposing_on_time
 - is_ffg_competitive

The head_weak and parent_strong functions I put into store ultimately, as it has all the context needed. It did mean a little restructuring to enable testing, but I think it currently is a sensible home for it.

partially addresses Consensys#6595

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

ethereum/spec/src/main/java/tech/pegasys/teku/spec/datastructures/forkchoice/ReadOnlyStore.java

@@ -134,4 +134,13 @@ default SafeFuture<Optional<BeaconBlock>> retrieveBlock(Bytes32 blockRoot) {
 
   SafeFuture<Optional<BeaconState>> retrieveCheckpointState(
       Checkpoint checkpoint, BeaconState latestStateAtEpoch);
+
+  // implements is_head_weak from fork-choice Consensus Spec
+  SafeFuture<Optional<Boolean>> isHeadWeak(final Bytes32 root);
+
+  // implements is_parent_strong from fork-choice Consensus Spec
+  SafeFuture<Optional<Boolean>> isParentStrong(final Bytes32 parentRoot);
+
+  // implements is_ffg_competitive from Consensus Spec
+  Optional<Boolean> isFfgCompetitive(final Bytes32 headRoot, final Bytes32 parentRoot);
 }

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

@@ -170,7 +170,7 @@ public Bytes32 getSeed(BeaconState state, UInt64 epoch, Bytes4 domainType)
    * @return
    */
   public UInt64 calculateCommitteeFraction(
-      final BeaconState beaconState, final UInt64 committeePercent) {
+      final BeaconState beaconState, final int committeePercent) {
     final UInt64 committeeWeight =
         getTotalActiveBalance(beaconState).dividedBy(config.getSlotsPerEpoch());
     return committeeWeight.times(committeePercent).dividedBy(100);

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

@@ -137,8 +137,7 @@ void calculateCommitteeFraction_full() {
         spec.atSlot(state.getSlot()).beaconStateAccessors().getTotalActiveBalance(state);
     final UInt64 totalActiveBalancePerSlot =
         totalActiveBalance.dividedBy(spec.getGenesisSpec().getSlotsPerEpoch());
-    final UInt64 fraction =
-        beaconStateAccessors.calculateCommitteeFraction(state, UInt64.valueOf(100));
+    final UInt64 fraction = beaconStateAccessors.calculateCommitteeFraction(state, 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);
@@ -151,7 +150,7 @@ void calculateCommitteeFraction_minimal() {
         spec.atSlot(state.getSlot()).beaconStateAccessors().getTotalActiveBalance(state);
     final UInt64 totalActiveBalancePerSlot =
         totalActiveBalance.dividedBy(spec.getGenesisSpec().getSlotsPerEpoch());
-    final UInt64 fraction = beaconStateAccessors.calculateCommitteeFraction(state, UInt64.ONE);
+    final UInt64 fraction = beaconStateAccessors.calculateCommitteeFraction(state, 1);
     // should be 1% of balance per slot...
     assertThat(fraction).isEqualTo(totalActiveBalancePerSlot.dividedBy(100));
   }

ethereum/spec/src/testFixtures/java/tech/pegasys/teku/spec/datastructures/forkchoice/TestStoreImpl.java

@@ -246,6 +246,21 @@ public SafeFuture<Optional<BeaconState>> retrieveCheckpointState(
     return SafeFuture.completedFuture(Optional.of(latestStateAtEpoch));
   }
 
+  @Override
+  public SafeFuture<Optional<Boolean>> isHeadWeak(Bytes32 root) {
+    return SafeFuture.completedFuture(Optional.empty());
+  }
+
+  @Override
+  public SafeFuture<Optional<Boolean>> isParentStrong(Bytes32 parentRoot) {
+    return SafeFuture.completedFuture(Optional.empty());
+  }
+
+  @Override
+  public Optional<Boolean> isFfgCompetitive(Bytes32 headRoot, Bytes32 parentRoot) {
+    return Optional.empty();
+  }
+
   @Override
   public Optional<List<BlobSidecar>> getBlobSidecarsIfAvailable(
       final SlotAndBlockRoot slotAndBlockRoot) {

storage/src/main/java/tech/pegasys/teku/storage/client/BlockTimelinessTracker.java

@@ -15,6 +15,8 @@
 
 import static tech.pegasys.teku.spec.constants.NetworkConstants.INTERVALS_PER_SLOT;
 
+import com.google.common.base.Supplier;
+import com.google.common.base.Suppliers;
 import java.util.Map;
 import java.util.Optional;
 import org.apache.logging.log4j.LogManager;
@@ -33,6 +35,9 @@ public class BlockTimelinessTracker {
   private final Spec spec;
   private final RecentChainData recentChainData;
 
+  private final Supplier<UInt64> genesisTimeSupplier;
+  private final Supplier<UInt64> genesisTimeMillisSupplier;
+
   // implements is_timely from Consensus Spec
   public BlockTimelinessTracker(
       final Spec spec, final RecentChainData recentChainData, final TimeProvider timeProvider) {
@@ -44,12 +49,14 @@ public BlockTimelinessTracker(
             spec.getGenesisSpec().getSlotsPerEpoch() * epochsForTimeliness);
     this.timeProvider = timeProvider;
     this.recentChainData = recentChainData;
+    this.genesisTimeSupplier = Suppliers.memoize(recentChainData::getGenesisTime);
+    this.genesisTimeMillisSupplier = Suppliers.memoize(recentChainData::getGenesisTimeMillis);
   }
 
   public void setBlockTimelinessFromArrivalTime(
       final SignedBeaconBlock block, final UInt64 arrivalTimeMillis) {
-    final UInt64 genesisTime = recentChainData.getGenesisTime();
-    final UInt64 computedSlot = spec.getCurrentSlot(timeProvider.getTimeInSeconds(), genesisTime);
+    final UInt64 computedSlot =
+        spec.getCurrentSlot(timeProvider.getTimeInSeconds(), genesisTimeSupplier.get());
     final Bytes32 root = block.getRoot();
     if (computedSlot.isGreaterThan(block.getMessage().getSlot())) {
       LOG.debug(
@@ -65,7 +72,7 @@ public void setBlockTimelinessFromArrivalTime(
         .ifPresent(
             slot -> {
               final UInt64 slotStartTimeMillis =
-                  spec.getSlotStartTimeMillis(slot, genesisTime.times(1000));
+                  spec.getSlotStartTimeMillis(slot, genesisTimeMillisSupplier.get());
               final int millisIntoSlot =
                   arrivalTimeMillis.minusMinZero(slotStartTimeMillis).intValue();
 
@@ -87,7 +94,34 @@ public void setBlockTimelinessFromArrivalTime(
             });
   }
 
-  public Optional<Boolean> isBlockTimely(final Bytes32 root) {
+  Optional<Boolean> isBlockTimely(final Bytes32 root) {
     return Optional.ofNullable(blockTimeliness.get(root));
   }
+
+  // is_proposing_on_time from consensus-spec
+  // 'on time' is before we're half-way to the attester time. logically, if the slot is 3 segments,
+  // then splitting into 6 segments is half-way to the attestation time.
+  public boolean isProposingOnTime(final UInt64 slot) {
+    final UInt64 slotStartTimeMillis =
+        spec.getSlotStartTimeMillis(slot, genesisTimeMillisSupplier.get());
+    final UInt64 timelinessLimit = spec.getMillisPerSlot(slot).dividedBy(INTERVALS_PER_SLOT * 2);
+    final UInt64 currentTimeMillis = timeProvider.getTimeInMillis();
+    final boolean isTimely =
+        currentTimeMillis.minusMinZero(slotStartTimeMillis).isLessThan(timelinessLimit);
+    LOG.debug(
+        "Check ProposingOnTime for slot {}, slot start time is {} ms and current time is {} ms, limit is {} ms result: {}",
+        slot,
+        slotStartTimeMillis,
+        currentTimeMillis,
+        timelinessLimit,
+        isTimely);
+    return isTimely;
+  }
+
+  // Implements is_head_late form consensus-spec
+  // caveat: if the root was not found, will default to it being timely,
+  // on the basis that it's not safe to make choices about blocks we don't know about
+  public boolean isBlockLate(final Bytes32 root) {
+    return !isBlockTimely(root).orElse(true);
+  }
 }

storage/src/main/java/tech/pegasys/teku/storage/client/RecentChainData.java

@@ -624,7 +624,12 @@ public void setBlockTimelinessFromArrivalTime(
     blockTimelinessTracker.setBlockTimelinessFromArrivalTime(block, arrivalTime);
   }
 
-  public Optional<Boolean> getBlockTimeliness(final Bytes32 blockRoot) {
-    return blockTimelinessTracker.isBlockTimely(blockRoot);
+  // implements is_head_late from consensus spec
+  public boolean isBlockLate(final Bytes32 blockRoot) {
+    return blockTimelinessTracker.isBlockLate(blockRoot);
+  }
+
+  public boolean isProposingOnTime(final UInt64 slot) {
+    return blockTimelinessTracker.isProposingOnTime(slot);
   }
 }