Improve fcu attributes calculation stability (Consensys#8009)

Author: tbenr

Diff for: ethereum/statetransition/src/main/java/tech/pegasys/teku/statetransition/forkchoice/ForkChoiceNotifierImpl.java

@@ -23,15 +23,14 @@
 import tech.pegasys.teku.infrastructure.time.TimeProvider;
 import tech.pegasys.teku.infrastructure.unsigned.UInt64;
 import tech.pegasys.teku.spec.Spec;
-import tech.pegasys.teku.spec.config.SpecConfig;
 import tech.pegasys.teku.spec.datastructures.execution.ExecutionPayloadContext;
 import tech.pegasys.teku.spec.executionlayer.ExecutionLayerChannel;
 import tech.pegasys.teku.spec.executionlayer.ForkChoiceState;
+import tech.pegasys.teku.spec.executionlayer.PayloadBuildingAttributes;
 import tech.pegasys.teku.statetransition.forkchoice.ForkChoiceUpdatedResultSubscriber.ForkChoiceUpdatedResultNotification;
-import tech.pegasys.teku.statetransition.forkchoice.ProposersDataManager.ProposersDataManagerSubscriber;
 import tech.pegasys.teku.storage.client.RecentChainData;
 
-public class ForkChoiceNotifierImpl implements ForkChoiceNotifier, ProposersDataManagerSubscriber {
+public class ForkChoiceNotifierImpl implements ForkChoiceNotifier {
   private static final Logger LOG = LogManager.getLogger();
 
   private final EventThread eventThread;
@@ -64,7 +63,6 @@ public ForkChoiceNotifierImpl(
     this.recentChainData = recentChainData;
     this.proposersDataManager = proposersDataManager;
     this.timeProvider = timeProvider;
-    proposersDataManager.subscribeToProposersDataChanges(this);
   }
 
   @Override
@@ -107,14 +105,6 @@ public boolean validatorIsConnected(UInt64 validatorIndex, UInt64 currentSlot) {
     return proposersDataManager.validatorIsConnected(validatorIndex, currentSlot);
   }
 
-  @Override
-  public void onPreparedProposersUpdated() {
-    eventThread.execute(this::internalUpdatePreparableProposers);
-  }
-
-  @Override
-  public void onValidatorRegistrationsUpdated() {}
-
   private void internalTerminalBlockReached(Bytes32 executionBlockHash) {
     eventThread.checkOnEventThread();
     LOG.debug("internalTerminalBlockReached executionBlockHash {}", executionBlockHash);
@@ -198,18 +188,6 @@ private SafeFuture<Optional<ExecutionPayloadContext>> internalGetPayloadId(
     }
   }
 
-  private void internalUpdatePreparableProposers() {
-    eventThread.checkOnEventThread();
-
-    LOG.debug("internalUpdatePreparableProposers");
-
-    // Default to the genesis slot if we're pre-genesis.
-    final UInt64 currentSlot = recentChainData.getCurrentSlot().orElse(SpecConfig.GENESIS_SLOT);
-
-    // Update payload attributes in case we now need to propose the next block
-    updatePayloadAttributes(currentSlot.plus(1));
-  }
-
   private void internalForkChoiceUpdated(
       final ForkChoiceState forkChoiceState, final Optional<UInt64> proposingSlot) {
     eventThread.checkOnEventThread();
@@ -220,14 +198,60 @@ private void internalForkChoiceUpdated(
 
     LOG.debug("internalForkChoiceUpdated forkChoiceUpdateData {}", forkChoiceUpdateData);
 
-    final Optional<UInt64> attributesSlot =
-        proposingSlot.or(() -> recentChainData.getCurrentSlot().map(UInt64::increment));
-
-    attributesSlot.ifPresent(this::updatePayloadAttributes);
+    calculatePayloadAttributesSlot(forkChoiceState, proposingSlot)
+        .ifPresent(this::updatePayloadAttributes);
 
     sendForkChoiceUpdated();
   }
 
+  /**
+   * Determine for which slot we should calculate payload attributes (block proposal)
+   *
+   * <pre>
+   * this will guarantee that whenever we calculate a payload attributes for a slot, it will remain stable until:
+   * 1. next slot attestation due is reached (internalAttestationsDue forcing attributes calculation for next slot)
+   * OR
+   * 2. we imported the block for current slot and has become the head
+   * </pre>
+   */
+  private Optional<UInt64> calculatePayloadAttributesSlot(
+      final ForkChoiceState forkChoiceState, final Optional<UInt64> proposingSlot) {
+    if (proposingSlot.isPresent()) {
+      // We are in the context of a block production, so we should use the proposing slot
+      return proposingSlot;
+    }
+
+    final Optional<UInt64> currentSlot = recentChainData.getCurrentSlot();
+    if (currentSlot.isEmpty()) {
+      // We are pre-genesis, so we don't care about proposing slots
+      return Optional.empty();
+    }
+
+    final Optional<UInt64> maybeCurrentPayloadAttributesSlot =
+        forkChoiceUpdateData
+            .getPayloadBuildingAttributes()
+            .map(PayloadBuildingAttributes::getProposalSlot);
+
+    if (maybeCurrentPayloadAttributesSlot.isPresent()
+        // we are still in the same slot as the last proposing slot
+        && currentSlot.get().equals(maybeCurrentPayloadAttributesSlot.get())
+        // we have not yet imported our own produced block
+        && forkChoiceState.getHeadBlockSlot().isLessThan(maybeCurrentPayloadAttributesSlot.get())) {
+
+      LOG.debug(
+          "current payload attributes slot has been chosen for payload attributes calculation: {}",
+          currentSlot.get());
+
+      // in case we propose two blocks in a row and we fail producing the first block,
+      // we won't keep using the same first slot because internalAttestationsDue will
+      // update the payload attributes for the second block slot
+      return currentSlot;
+    }
+
+    // chain advanced since last proposing slot, we should consider attributes for the next slot
+    return currentSlot.map(UInt64::increment);
+  }
+
   private void internalAttestationsDue(final UInt64 slot) {
     eventThread.checkOnEventThread();
 

Diff for: ethereum/statetransition/src/main/java/tech/pegasys/teku/statetransition/forkchoice/ProposersDataManager.java

@@ -30,7 +30,6 @@
 import tech.pegasys.teku.infrastructure.async.eventthread.EventThread;
 import tech.pegasys.teku.infrastructure.metrics.TekuMetricCategory;
 import tech.pegasys.teku.infrastructure.ssz.SszList;
-import tech.pegasys.teku.infrastructure.subscribers.Subscribers;
 import tech.pegasys.teku.infrastructure.unsigned.UInt64;
 import tech.pegasys.teku.spec.Spec;
 import tech.pegasys.teku.spec.datastructures.blocks.SlotAndBlockRoot;
@@ -59,9 +58,6 @@ public class ProposersDataManager implements SlotEventsChannel {
   private final Optional<Eth1Address> proposerDefaultFeeRecipient;
   private final boolean forkChoiceUpdatedAlwaysSendPayloadAttribute;
 
-  private final Subscribers<ProposersDataManagerSubscriber> proposersDataChangesSubscribers =
-      Subscribers.create(true);
-
   public ProposersDataManager(
       final EventThread eventThread,
       final Spec spec,
@@ -88,10 +84,6 @@ public ProposersDataManager(
     this.forkChoiceUpdatedAlwaysSendPayloadAttribute = forkChoiceUpdatedAlwaysSendPayloadAttribute;
   }
 
-  public void subscribeToProposersDataChanges(final ProposersDataManagerSubscriber subscriber) {
-    proposersDataChangesSubscribers.subscribe(subscriber);
-  }
-
   @Override
   public void onSlot(UInt64 slot) {
     // do clean up in the middle of the epoch
@@ -125,8 +117,6 @@ public void onSlot(UInt64 slot) {
   public void updatePreparedProposers(
       final Collection<BeaconPreparableProposer> preparedProposers, final UInt64 currentSlot) {
     updatePreparedProposerCache(preparedProposers, currentSlot);
-    proposersDataChangesSubscribers.deliver(
-        ProposersDataManagerSubscriber::onPreparedProposersUpdated);
   }
 
   public SafeFuture<Void> updateValidatorRegistrations(
@@ -180,9 +170,6 @@ private void updateValidatorRegistrationCache(
                         LOG.warn(
                             "validator index not found for public key {}",
                             signedValidatorRegistration.getMessage().getPublicKey())));
-
-    proposersDataChangesSubscribers.deliver(
-        ProposersDataManagerSubscriber::onValidatorRegistrationsUpdated);
   }
 
   public SafeFuture<Optional<PayloadBuildingAttributes>> calculatePayloadBuildingAttributes(
@@ -302,10 +289,4 @@ public Map<UInt64, RegisteredValidatorInfo> getValidatorRegistrationInfo() {
   public boolean isProposerDefaultFeeRecipientDefined() {
     return proposerDefaultFeeRecipient.isPresent();
   }
-
-  public interface ProposersDataManagerSubscriber {
-    void onPreparedProposersUpdated();
-
-    void onValidatorRegistrationsUpdated();
-  }
 }

Diff for: ethereum/statetransition/src/test/java/tech/pegasys/teku/statetransition/forkchoice/ForkChoiceNotifierTest.java

@@ -258,6 +258,50 @@ void onForkChoiceUpdated_shouldSendNotificationWithPayloadBuildingAttributesForN
     verify(executionLayerChannel).engineForkChoiceUpdated(forkChoiceState, Optional.empty());
   }
 
+  @Test
+  void onForkChoiceUpdated_shouldSendNotificationWithStableSlot() {
+    final ForkChoiceState forkChoiceState = getCurrentForkChoiceState();
+    final BeaconState headState = getHeadState();
+
+    // setup two block productions in a row
+    final UInt64 blockSlot = headState.getSlot().plus(1);
+    final UInt64 nextBlockSlot = headState.getSlot().plus(2);
+
+    final List<PayloadBuildingAttributes> payloadBuildingAttributes =
+        withProposerForTwoSlots(forkChoiceState, headState, blockSlot, nextBlockSlot);
+
+    storageSystem.chainUpdater().setCurrentSlot(blockSlot);
+
+    notifyForkChoiceUpdated(forkChoiceState, Optional.of(blockSlot));
+    verify(executionLayerChannel)
+        .engineForkChoiceUpdated(forkChoiceState, Optional.of(payloadBuildingAttributes.get(0)));
+
+    assertThat(recentChainData.getCurrentSlot()).contains(blockSlot);
+
+    // fcu call with same state but no proposerSlot should not cause a new call to the EL
+    notifyForkChoiceUpdatedVerifyNoNotification(forkChoiceState);
+    verifyNoMoreInteractions(executionLayerChannel);
+
+    // when attestation due arrives, the next proposer attributes should be sent
+    forkChoiceUpdatedResultNotification = null;
+    notifier.onAttestationsDue(blockSlot);
+    assertThat(forkChoiceUpdatedResultNotification).isNotNull();
+    assertThat(forkChoiceUpdatedResultNotification.payloadAttributes())
+        .contains(payloadBuildingAttributes.get(1));
+    verify(executionLayerChannel)
+        .engineForkChoiceUpdated(forkChoiceState, Optional.of(payloadBuildingAttributes.get(1)));
+
+    // we are still on blockSlot, with EL already notified to build nextBlockSlot
+    notifyForkChoiceUpdatedVerifyNoNotification(forkChoiceState);
+    verifyNoMoreInteractions(executionLayerChannel);
+
+    storageSystem.chainUpdater().setCurrentSlot(nextBlockSlot);
+
+    // we are asked to build nextBlockSlot, EL is already notified for that
+    notifyForkChoiceUpdatedVerifyNoNotification(forkChoiceState, Optional.of(nextBlockSlot));
+    verifyNoMoreInteractions(executionLayerChannel);
+  }
+
   @Test
   void
       onForkChoiceUpdated_shouldSendNotificationWithPayloadBuildingAttributesIfConfiguredToAlwaysSendThem() {
@@ -378,11 +422,7 @@ void onForkChoiceUpdated_shouldSendNotificationOfOrderedPayloadBuildingAttribute
     verify(executionLayerChannel)
         .engineForkChoiceUpdated(forkChoiceState, Optional.of(payloadBuildingAttributes.get(0)));
 
-    storageSystem
-        .chainUpdater()
-        .setCurrentSlot(headState.getSlot().plus(1)); // set current slot to 2
-
-    notifyForkChoiceUpdated(forkChoiceState); // calculate attributes for slot 3
+    notifier.onAttestationsDue(blockSlot); // calculate attributes for slot 3
 
     // expect attributes for slot 3
     verify(executionLayerChannel)
@@ -569,18 +609,16 @@ void onPreparedProposersUpdated_shouldNotIncludePayloadBuildingAttributesWhileSy
   }
 
   @Test
-  void onPreparedProposersUpdated_shouldSendNewNotificationWhenProposerAdded() {
+  void onPreparedProposersUpdated_shouldNotCallForkChoiceUpdated() {
     final ForkChoiceState forkChoiceState = getCurrentForkChoiceState();
     final BeaconState headState = getHeadState();
     final UInt64 blockSlot = headState.getSlot().plus(1);
 
     notifyForkChoiceUpdated(forkChoiceState);
     verify(executionLayerChannel).engineForkChoiceUpdated(forkChoiceState, Optional.empty());
 
-    final PayloadBuildingAttributes payloadBuildingAttributes =
-        withProposerForSlot(forkChoiceState, headState, blockSlot);
-    verify(executionLayerChannel)
-        .engineForkChoiceUpdated(forkChoiceState, Optional.of(payloadBuildingAttributes));
+    withProposerForSlot(forkChoiceState, headState, blockSlot);
+    verifyNoMoreInteractions(executionLayerChannel);
   }
 
   @Test
@@ -882,6 +920,17 @@ private void notifyForkChoiceUpdated(final ForkChoiceState forkChoiceState) {
     notifyForkChoiceUpdated(forkChoiceState, Optional.empty());
   }
 
+  private void notifyForkChoiceUpdatedVerifyNoNotification(final ForkChoiceState forkChoiceState) {
+    notifyForkChoiceUpdated(
+        forkChoiceState, Optional.empty(), notification -> assertThat(notification).isNull());
+  }
+
+  private void notifyForkChoiceUpdatedVerifyNoNotification(
+      final ForkChoiceState forkChoiceState, final Optional<UInt64> proposingSlot) {
+    notifyForkChoiceUpdated(
+        forkChoiceState, proposingSlot, notification -> assertThat(notification).isNull());
+  }
+
   private void notifyForkChoiceUpdated(
       final ForkChoiceState forkChoiceState, final Optional<UInt64> proposingSlot) {
     notifyForkChoiceUpdated(

Diff for: ethereum/statetransition/src/test/java/tech/pegasys/teku/statetransition/forkchoice/ProposerDataManagerTest.java

@@ -38,10 +38,9 @@
 import tech.pegasys.teku.spec.datastructures.state.beaconstate.BeaconState;
 import tech.pegasys.teku.spec.executionlayer.ExecutionLayerChannel;
 import tech.pegasys.teku.spec.util.DataStructureUtil;
-import tech.pegasys.teku.statetransition.forkchoice.ProposersDataManager.ProposersDataManagerSubscriber;
 import tech.pegasys.teku.storage.client.RecentChainData;
 
-public class ProposerDataManagerTest implements ProposersDataManagerSubscriber {
+public class ProposerDataManagerTest {
   private final InlineEventThread eventThread = new InlineEventThread();
   private final Spec spec = TestSpecFactory.createMinimalBellatrix();
   private final Spec specMock = mock(Spec.class);
@@ -65,9 +64,6 @@ public class ProposerDataManagerTest implements ProposersDataManagerSubscriber {
 
   private final BeaconState state = dataStructureUtil.randomBeaconState();
 
-  private boolean onValidatorRegistrationsUpdatedCalled = false;
-  private boolean onPreparedProposerUpdatedCalled = false;
-
   private final UInt64 slot = UInt64.ONE;
   private SszList<SignedValidatorRegistration> registrations;
   private final SafeFuture<Void> response = new SafeFuture<>();
@@ -80,7 +76,6 @@ void shouldCallRegisterValidator() {
     final SafeFuture<Void> updateCall =
         proposersDataManager.updateValidatorRegistrations(registrations, slot);
 
-    assertThat(onValidatorRegistrationsUpdatedCalled).isFalse();
     verify(executionLayerChannel).builderRegisterValidators(registrations, slot);
     verifyNoMoreInteractions(executionLayerChannel);
 
@@ -89,7 +84,6 @@ void shouldCallRegisterValidator() {
     assertThat(updateCall).isCompleted();
 
     // final update
-    assertThat(onValidatorRegistrationsUpdatedCalled).isTrue();
     assertRegisteredValidatorsCount(2);
   }
 
@@ -101,14 +95,12 @@ void shouldNotSignalValidatorRegistrationUpdatedOnError() {
     final SafeFuture<Void> updateCall =
         proposersDataManager.updateValidatorRegistrations(registrations, slot);
 
-    assertThat(onValidatorRegistrationsUpdatedCalled).isFalse();
     verify(executionLayerChannel).builderRegisterValidators(registrations, slot);
 
     response.completeExceptionally(new RuntimeException("generic error"));
 
     assertThat(updateCall).isCompletedExceptionally();
 
-    assertThat(onValidatorRegistrationsUpdatedCalled).isFalse();
     verifyNoMoreInteractions(executionLayerChannel);
     assertRegisteredValidatorsCount(0);
   }
@@ -128,8 +120,6 @@ void shouldSignalAllDataUpdatedAndShouldExpireData() {
                 dataStructureUtil.randomUInt64(), dataStructureUtil.randomEth1Address())),
         slot);
 
-    assertThat(onValidatorRegistrationsUpdatedCalled).isTrue();
-    assertThat(onPreparedProposerUpdatedCalled).isTrue();
     assertRegisteredValidatorsCount(2);
     assertPreparedProposersCount(1);
 
@@ -160,8 +150,6 @@ private void prepareRegistrations() {
     when(specMock.getValidatorIndex(state, registrations.get(1).getMessage().getPublicKey()))
         .thenReturn(Optional.of(1));
     when(specMock.getSlotsPerEpoch(any())).thenReturn(spec.getSlotsPerEpoch(slot));
-
-    proposersDataManager.subscribeToProposersDataChanges(this);
   }
 
   private void assertPreparedProposersCount(final int expectedCount) {
@@ -179,14 +167,4 @@ private void assertRegisteredValidatorsCount(final int expectedCount) {
             .getValue("registered_validators");
     assertThat(optionalValue).hasValue(expectedCount);
   }
-
-  @Override
-  public void onPreparedProposersUpdated() {
-    onPreparedProposerUpdatedCalled = true;
-  }
-
-  @Override
-  public void onValidatorRegistrationsUpdated() {
-    onValidatorRegistrationsUpdatedCalled = true;
-  }
 }