Fix: WarpSync

pkg/protocol/chain.go

@@ -48,9 +48,8 @@ type Chain struct {
 	// WarpSyncMode contains a flag that indicates whether this chain is in warp sync mode.
 	WarpSyncMode reactive.Variable[bool]
 
-	// WarpSyncThreshold contains the slot at which the chain will exit warp sync mode which is derived from the latest
-	// network slot minus the max committable age.
-	WarpSyncThreshold reactive.Variable[iotago.SlotIndex]
+	// LatestSyncedSlot contains the latest commitment of this chain for which all blocks were booked.
+	LatestSyncedSlot reactive.Variable[iotago.SlotIndex]
 
 	// OutOfSyncThreshold contains the slot at which the chain will consider itself to be out of sync and switch to warp
 	// sync mode. It is derived from the latest network slot minus two times the max committable age.
@@ -93,7 +92,7 @@ func newChain(chains *Chains) *Chain {
 		AttestedWeight:           reactive.NewVariable[uint64](),
 		VerifiedWeight:           reactive.NewVariable[uint64](),
 		WarpSyncMode:             reactive.NewVariable[bool]().Init(true),
-		WarpSyncThreshold:        reactive.NewVariable[iotago.SlotIndex](),
+		LatestSyncedSlot:         reactive.NewVariable[iotago.SlotIndex](),
 		OutOfSyncThreshold:       reactive.NewVariable[iotago.SlotIndex](),
 		RequestAttestations:      reactive.NewVariable[bool](),
 		StartEngine:              reactive.NewVariable[bool](),
@@ -187,13 +186,14 @@ func (c *Chain) initLogger() (shutdown func()) {
 
 	return lo.Batch(
 		c.WarpSyncMode.LogUpdates(c, log.LevelTrace, "WarpSyncMode"),
-		c.WarpSyncThreshold.LogUpdates(c, log.LevelTrace, "WarpSyncThreshold"),
+		c.LatestSyncedSlot.LogUpdates(c, log.LevelTrace, "LatestSyncedSlot"),
 		c.OutOfSyncThreshold.LogUpdates(c, log.LevelTrace, "OutOfSyncThreshold"),
 		c.ForkingPoint.LogUpdates(c, log.LevelTrace, "ForkingPoint", (*Commitment).LogName),
 		c.ClaimedWeight.LogUpdates(c, log.LevelTrace, "ClaimedWeight"),
 		c.AttestedWeight.LogUpdates(c, log.LevelTrace, "AttestedWeight"),
 		c.VerifiedWeight.LogUpdates(c, log.LevelTrace, "VerifiedWeight"),
 		c.LatestCommitment.LogUpdates(c, log.LevelTrace, "LatestCommitment", (*Commitment).LogName),
+		c.LatestAttestedCommitment.LogUpdates(c, log.LevelTrace, "LatestAttestedCommitment", (*Commitment).LogName),
 		c.LatestProducedCommitment.LogUpdates(c, log.LevelDebug, "LatestProducedCommitment", (*Commitment).LogName),
 		c.RequestAttestations.LogUpdates(c, log.LevelTrace, "RequestAttestations"),
 		c.StartEngine.LogUpdates(c, log.LevelDebug, "StartEngine"),
@@ -212,39 +212,23 @@ func (c *Chain) initDerivedProperties() (shutdown func()) {
 		c.deriveLatestAttestedWeight(),
 		c.deriveWarpSyncMode(),
 
-		c.ForkingPoint.WithValue(func(forkingPoint *Commitment) (shutdown func()) {
-			return c.deriveParentChain(forkingPoint)
-		}),
-
-		c.ParentChain.WithNonEmptyValue(func(parentChain *Chain) (shutdown func()) {
-			return parentChain.deriveChildChains(c)
-		}),
-
-		c.Engine.WithNonEmptyValue(func(engineInstance *engine.Engine) (shutdown func()) {
-			return lo.Batch(
-				c.deriveWarpSyncThreshold(c.chains.LatestSeenSlot, engineInstance),
-				c.deriveOutOfSyncThreshold(c.chains.LatestSeenSlot, engineInstance),
-			)
-		}),
+		c.ForkingPoint.WithValue(c.deriveParentChain),
+		c.ParentChain.WithNonEmptyValue(lo.Bind(c, (*Chain).deriveChildChains)),
+		c.Engine.WithNonEmptyValue(c.deriveOutOfSyncThreshold),
 	)
 }
 
 // deriveWarpSyncMode defines how a chain determines whether it is in warp sync mode or not.
 func (c *Chain) deriveWarpSyncMode() func() {
-	return c.WarpSyncMode.DeriveValueFrom(reactive.NewDerivedVariable3(func(warpSyncMode bool, latestProducedCommitment *Commitment, warpSyncThreshold iotago.SlotIndex, outOfSyncThreshold iotago.SlotIndex) bool {
-		// if we have no latest produced commitment, then the engine is not yet initialized and warp sync is disabled
-		if latestProducedCommitment == nil {
-			return false
-		}
-
-		// if warp sync mode is enabled, keep it enabled until we are no longer below the warp sync threshold
+	return c.WarpSyncMode.DeriveValueFrom(reactive.NewDerivedVariable3(func(warpSyncMode bool, latestSyncedSlot iotago.SlotIndex, latestSeenSlot iotago.SlotIndex, outOfSyncThreshold iotago.SlotIndex) bool {
+		// if warp sync mode is enabled, keep it enabled until we have synced all slots
 		if warpSyncMode {
-			return latestProducedCommitment.ID().Slot() < warpSyncThreshold
+			return latestSyncedSlot < latestSeenSlot
 		}
 
 		// if warp sync mode is disabled, enable it only if we fall below the out of sync threshold
-		return latestProducedCommitment.ID().Slot() < outOfSyncThreshold
-	}, c.LatestProducedCommitment, c.WarpSyncThreshold, c.OutOfSyncThreshold, c.WarpSyncMode.Get()))
+		return latestSyncedSlot < outOfSyncThreshold
+	}, c.LatestSyncedSlot, c.chains.LatestSeenSlot, c.OutOfSyncThreshold, c.WarpSyncMode.Get()))
 }
 
 // deriveClaimedWeight defines how a chain determines its claimed weight (by setting the cumulative weight of the
@@ -311,26 +295,14 @@ func (c *Chain) deriveParentChain(forkingPoint *Commitment) (shutdown func()) {
 
 // deriveOutOfSyncThreshold defines how a chain determines its "out of sync" threshold (the latest seen slot minus 2
 // times the max committable age or 0 if this would cause an overflow to the negative numbers).
-func (c *Chain) deriveOutOfSyncThreshold(latestSeenSlot reactive.ReadableVariable[iotago.SlotIndex], engineInstance *engine.Engine) func() {
+func (c *Chain) deriveOutOfSyncThreshold(engineInstance *engine.Engine) func() {
 	return c.OutOfSyncThreshold.DeriveValueFrom(reactive.NewDerivedVariable(func(_ iotago.SlotIndex, latestSeenSlot iotago.SlotIndex) iotago.SlotIndex {
 		if outOfSyncOffset := 2 * engineInstance.LatestAPI().ProtocolParameters().MaxCommittableAge(); outOfSyncOffset < latestSeenSlot {
 			return latestSeenSlot - outOfSyncOffset
 		}
 
 		return 0
-	}, latestSeenSlot))
-}
-
-// deriveWarpSyncThreshold defines how a chain determines its warp sync threshold (the latest seen slot minus the max
-// committable age or 0 if this would cause an overflow to the negative numbers).
-func (c *Chain) deriveWarpSyncThreshold(latestSeenSlot reactive.ReadableVariable[iotago.SlotIndex], engineInstance *engine.Engine) func() {
-	return c.WarpSyncThreshold.DeriveValueFrom(reactive.NewDerivedVariable(func(_ iotago.SlotIndex, latestSeenSlot iotago.SlotIndex) iotago.SlotIndex {
-		if warpSyncOffset := engineInstance.LatestAPI().ProtocolParameters().MaxCommittableAge(); warpSyncOffset < latestSeenSlot {
-			return latestSeenSlot - warpSyncOffset
-		}
-
-		return 0
-	}, latestSeenSlot))
+	}, c.chains.LatestSeenSlot))
 }
 
 // addCommitment adds the given commitment to this chain.
@@ -342,6 +314,7 @@ func (c *Chain) addCommitment(newCommitment *Commitment) (shutdown func()) {
 	return lo.Batch(
 		newCommitment.IsAttested.OnTrigger(func() { c.LatestAttestedCommitment.Set(newCommitment) }),
 		newCommitment.IsVerified.OnTrigger(func() { c.LatestProducedCommitment.Set(newCommitment) }),
+		newCommitment.IsSynced.OnTrigger(func() { c.LatestSyncedSlot.Set(newCommitment.Slot()) }),
 	)
 }
 

pkg/protocol/chains.go

@@ -31,7 +31,7 @@ type Chains struct {
 	// HeaviestVerifiedCandidate contains the candidate chain with the heaviest verified weight.
 	HeaviestVerifiedCandidate reactive.Variable[*Chain]
 
-	// LatestSeenSlot contains the latest slot that was seen by any of the chains.
+	// LatestSeenSlot contains the slot of the latest commitment of any received block.
 	LatestSeenSlot reactive.Variable[iotago.SlotIndex]
 
 	// protocol contains a reference to the Protocol instance that this component belongs to.
@@ -158,7 +158,7 @@ func (c *Chains) deriveLatestSeenSlot(protocol *Protocol) func() {
 			}),
 
 			protocol.Network.OnBlockReceived(func(block *model.Block, src peer.ID) {
-				c.LatestSeenSlot.Set(mainEngine.LatestAPI().TimeProvider().SlotFromTime(block.ProtocolBlock().Header.IssuingTime))
+				c.LatestSeenSlot.Set(block.ProtocolBlock().Header.SlotCommitmentID.Slot())
 			}),
 		)
 	})

pkg/protocol/commitment.go

@@ -56,6 +56,12 @@ type Commitment struct {
 	// IsAttested contains a flag indicating if we have received attestations for this Commitment.
 	IsAttested reactive.Event
 
+	// IsSynced contains a flag that indicates if a Commitment was fully downloaded and processed.
+	IsSynced reactive.Event
+
+	// IsCommittable contains a flag that indicates if a Commitment is ready to be committed by the warp sync process.
+	IsCommittable reactive.Event
+
 	// IsVerified contains a flag indicating if this Commitment is verified (we produced this Commitment ourselves by
 	// booking all the contained blocks and transactions).
 	IsVerified reactive.Event
@@ -65,7 +71,7 @@ type Commitment struct {
 	IsAboveLatestVerifiedCommitment reactive.Variable[bool]
 
 	// ReplayDroppedBlocks contains a flag indicating if we should replay the blocks that were dropped while the
-	//Commitment was pending.
+	// Commitment was pending.
 	ReplayDroppedBlocks reactive.Variable[bool]
 
 	// IsEvicted contains a flag indicating if this Commitment was evicted from the Protocol.
@@ -94,6 +100,8 @@ func newCommitment(commitments *Commitments, model *model.Commitment) *Commitmen
 		CumulativeAttestedWeight:        reactive.NewVariable[uint64](),
 		IsRoot:                          reactive.NewEvent(),
 		IsAttested:                      reactive.NewEvent(),
+		IsSynced:                        reactive.NewEvent(),
+		IsCommittable:                   reactive.NewEvent(),
 		IsVerified:                      reactive.NewEvent(),
 		IsAboveLatestVerifiedCommitment: reactive.NewVariable[bool](),
 		ReplayDroppedBlocks:             reactive.NewVariable[bool](),
@@ -135,6 +143,8 @@ func (c *Commitment) initLogger() (shutdown func()) {
 		c.CumulativeAttestedWeight.LogUpdates(c, log.LevelTrace, "CumulativeAttestedWeight"),
 		c.IsRoot.LogUpdates(c, log.LevelTrace, "IsRoot"),
 		c.IsAttested.LogUpdates(c, log.LevelTrace, "IsAttested"),
+		c.IsSynced.LogUpdates(c, log.LevelTrace, "IsSynced"),
+		c.IsCommittable.LogUpdates(c, log.LevelTrace, "IsCommittable"),
 		c.IsVerified.LogUpdates(c, log.LevelTrace, "IsVerified"),
 		c.ReplayDroppedBlocks.LogUpdates(c, log.LevelTrace, "ReplayDroppedBlocks"),
 		c.IsEvicted.LogUpdates(c, log.LevelTrace, "IsEvicted"),
@@ -149,8 +159,9 @@ func (c *Commitment) initDerivedProperties() (shutdown func()) {
 		// mark commitments that are marked as root as verified
 		c.IsVerified.InheritFrom(c.IsRoot),
 
-		// mark commitments that are marked as verified as attested
+		// mark commitments that are marked as verified as attested and synced
 		c.IsAttested.InheritFrom(c.IsVerified),
+		c.IsSynced.InheritFrom(c.IsVerified),
 
 		c.Parent.WithNonEmptyValue(func(parent *Commitment) func() {
 			// the weight can be fixed as a one time operation (as it only relies on static information from the parent
@@ -167,7 +178,11 @@ func (c *Commitment) initDerivedProperties() (shutdown func()) {
 				c.Chain.WithNonEmptyValue(func(chain *Chain) func() {
 					return lo.Batch(
 						c.deriveRequestAttestations(chain, parent),
-						c.deriveWarpSyncBlocks(chain, parent),
+
+						// only start requesting blocks once the engine is ready
+						chain.WithInitializedEngine(func(_ *engine.Engine) (shutdown func()) {
+							return c.deriveWarpSyncBlocks(chain, parent)
+						}),
 					)
 				}),
 			)
@@ -259,11 +274,11 @@ func (c *Commitment) deriveRequestAttestations(chain *Chain, parent *Commitment)
 }
 
 // deriveWarpSyncBlocks derives the WarpSyncBlocks flag of this Commitment which is true if our Chain is requesting
-// warp sync, and we are the directly above the latest verified Commitment.
+// warp sync, and we are the directly above the latest commitment that is synced (has downloaded everything).
 func (c *Commitment) deriveWarpSyncBlocks(chain *Chain, parent *Commitment) func() {
-	return c.WarpSyncBlocks.DeriveValueFrom(reactive.NewDerivedVariable4(func(_ bool, engineInstance *engine.Engine, warpSync bool, parentIsVerified bool, isVerified bool) bool {
-		return engineInstance != nil && warpSync && parentIsVerified && !isVerified
-	}, chain.Engine, chain.WarpSyncMode, parent.IsVerified, c.IsVerified))
+	return c.WarpSyncBlocks.DeriveValueFrom(reactive.NewDerivedVariable3(func(_ bool, warpSyncMode bool, parentIsSynced bool, isSynced bool) bool {
+		return warpSyncMode && parentIsSynced && !isSynced
+	}, chain.WarpSyncMode, parent.IsSynced, c.IsSynced))
 }
 
 // deriveReplayDroppedBlocks derives the ReplayDroppedBlocks flag of this Commitment which is true if our Chain has an
@@ -278,7 +293,7 @@ func (c *Commitment) deriveReplayDroppedBlocks(chain *Chain) func() {
 // the parent is on the target Chain.
 func (c *Commitment) forceChain(targetChain *Chain) {
 	if currentChain := c.Chain.Get(); currentChain != targetChain {
-		if parent := c.Parent.Get(); parent.Chain.Get() == targetChain {
+		if parent := c.Parent.Get(); parent != nil && parent.Chain.Get() == targetChain {
 			parent.MainChild.Set(c)
 		}
 	}

pkg/protocol/commitment_verifier.go

@@ -5,6 +5,7 @@ import (
 	"github.com/iotaledger/hive.go/ds"
 	"github.com/iotaledger/hive.go/ierrors"
 	"github.com/iotaledger/hive.go/kvstore/mapdb"
+	"github.com/iotaledger/hive.go/runtime/syncutils"
 	"github.com/iotaledger/iota-core/pkg/model"
 	"github.com/iotaledger/iota-core/pkg/protocol/engine"
 	"github.com/iotaledger/iota-core/pkg/protocol/engine/accounts"
@@ -22,6 +23,9 @@ type CommitmentVerifier struct {
 	// validatorAccountsData is the accounts data of the validators for the current epoch as known at lastCommonSlotBeforeFork.
 	// Initially, it is set to the accounts data of the validators for the epoch of the last common commitment before the fork.
 	validatorAccountsData map[iotago.AccountID]*accounts.AccountData
+
+	// mutex is used to synchronize access to validatorAccountsData and epoch.
+	mutex syncutils.RWMutex
 }
 
 func newCommitmentVerifier(mainEngine *engine.Engine, lastCommonCommitmentBeforeFork *model.Commitment) (*CommitmentVerifier, error) {
@@ -76,6 +80,7 @@ func (c *CommitmentVerifier) verifyCommitment(commitment *Commitment, attestatio
 	//    This is necessary because the committee might have rotated at the epoch boundary and different validators might be part of it.
 	//    In case anything goes wrong we keep using previously known accounts data (initially set to the accounts data
 	//    of the validators for the epoch of the last common commitment before the fork).
+	c.mutex.Lock()
 	apiForSlot := c.engine.APIForSlot(commitment.Slot())
 	commitmentEpoch := apiForSlot.TimeProvider().EpochFromSlot(commitment.Slot())
 	if commitmentEpoch > c.epoch {
@@ -92,6 +97,7 @@ func (c *CommitmentVerifier) verifyCommitment(commitment *Commitment, attestatio
 			}
 		}
 	}
+	c.mutex.Unlock()
 
 	// 3. Verify attestations.
 	blockIDs, seatCount, err := c.verifyAttestations(attestations)
@@ -107,6 +113,9 @@ func (c *CommitmentVerifier) verifyCommitment(commitment *Commitment, attestatio
 }
 
 func (c *CommitmentVerifier) verifyAttestations(attestations []*iotago.Attestation) (iotago.BlockIDs, uint64, error) {
+	c.mutex.RLock()
+	defer c.mutex.RUnlock()
+
 	visitedIdentities := ds.NewSet[iotago.AccountID]()
 	var blockIDs iotago.BlockIDs
 	var seatCount uint64

pkg/protocol/engine/blocks/block.go

@@ -49,7 +49,7 @@ type Block struct {
 	dropped   bool
 
 	// Notarization
-	notarized reactive.Variable[bool]
+	notarized reactive.Event
 
 	mutex syncutils.RWMutex
 
@@ -88,7 +88,7 @@ func NewBlock(data *model.Block) *Block {
 		booked:                reactive.NewVariable[bool](),
 		accepted:              reactive.NewVariable[bool](),
 		weightPropagated:      reactive.NewVariable[bool](),
-		notarized:             reactive.NewVariable[bool](),
+		notarized:             reactive.NewEvent(),
 		workScore:             data.WorkScore(),
 	}
 }
@@ -112,7 +112,7 @@ func NewRootBlock(blockID iotago.BlockID, commitmentID iotago.CommitmentID, issu
 		preAccepted:      true,
 		accepted:         reactive.NewVariable[bool](),
 		weightPropagated: reactive.NewVariable[bool](),
-		notarized:        reactive.NewVariable[bool](),
+		notarized:        reactive.NewEvent(),
 		scheduled:        true,
 	}
 
@@ -140,7 +140,7 @@ func NewMissingBlock(blockID iotago.BlockID) *Block {
 		booked:                reactive.NewVariable[bool](),
 		accepted:              reactive.NewVariable[bool](),
 		weightPropagated:      reactive.NewVariable[bool](),
-		notarized:             reactive.NewVariable[bool](),
+		notarized:             reactive.NewEvent(),
 	}
 }
 
@@ -622,7 +622,7 @@ func (b *Block) SetWeightPropagated() (wasUpdated bool) {
 	return !b.weightPropagated.Set(true)
 }
 
-func (b *Block) Notarized() reactive.Variable[bool] {
+func (b *Block) Notarized() reactive.Event {
 	return b.notarized
 }
 
@@ -631,7 +631,7 @@ func (b *Block) IsNotarized() (isBooked bool) {
 }
 
 func (b *Block) SetNotarized() (wasUpdated bool) {
-	return !b.notarized.Set(true)
+	return b.notarized.Trigger()
 }
 
 func (b *Block) String() string {

pkg/protocol/protocol.go

@@ -89,7 +89,7 @@ func New(logger log.Logger, workers *workerpool.Group, networkEndpoint network.E
 
 		p.Constructed.Trigger()
 
-		p.waitMainEngineInitialized()
+		p.waitInitialized()
 	})
 }
 
@@ -204,14 +204,14 @@ func (p *Protocol) initNetwork() (shutdown func()) {
 	)
 }
 
-// waitMainEngineInitialized waits until the main engine is initialized.
-func (p *Protocol) waitMainEngineInitialized() {
+// waitInitialized waits until the main engine is initialized (published its root commitment).
+func (p *Protocol) waitInitialized() {
 	var waitInitialized sync.WaitGroup
 
 	waitInitialized.Add(1)
-	p.Engines.Main.OnUpdateOnce(func(_ *engine.Engine, engine *engine.Engine) {
-		engine.Initialized.OnTrigger(waitInitialized.Done)
-	})
+	p.Commitments.Root.OnUpdateOnce(func(_ *Commitment, _ *Commitment) {
+		waitInitialized.Done()
+	}, func(_ *Commitment, rootCommitment *Commitment) bool { return rootCommitment != nil })
 
 	waitInitialized.Wait()
 }

pkg/protocol/protocol_attestations.go

@@ -30,7 +30,7 @@ type AttestationsProtocol struct {
 	// commitmentVerifiers contains the commitment verifiers that are used to verify received attestations.
 	commitmentVerifiers *shrinkingmap.ShrinkingMap[iotago.CommitmentID, *CommitmentVerifier]
 
-	// Logger embeds a logger that can be used to log messages emitted by this chain.
+	// Logger embeds a logger that can be used to log messages emitted by this component.
 	log.Logger
 }
 

pkg/protocol/protocol_blocks.go

@@ -53,21 +53,12 @@ func newBlocksProtocol(protocol *Protocol) *BlocksProtocol {
 			})
 		})
 
-		protocol.Chains.WithElements(func(chain *Chain) func() {
-			return chain.Engine.WithNonEmptyValue(func(engineInstance *engine.Engine) (shutdown func()) {
-				return engineInstance.Events.BlockRequester.Tick.Hook(b.SendRequest).Unhook
-			})
-		})
-
-		protocol.Chains.Main.Get().Engine.OnUpdateWithContext(func(_ *engine.Engine, engine *engine.Engine, unsubscribeOnEngineChange func(subscriptionFactory func() (unsubscribe func()))) {
-			if engine != nil {
-				unsubscribeOnEngineChange(func() (unsubscribe func()) {
-					return lo.Batch(
-						engine.Events.Scheduler.BlockScheduled.Hook(func(block *blocks.Block) { b.SendResponse(block.ModelBlock()) }).Unhook,
-						engine.Events.Scheduler.BlockSkipped.Hook(func(block *blocks.Block) { b.SendResponse(block.ModelBlock()) }).Unhook,
-					)
-				})
-			}
+		protocol.Chains.WithInitializedEngines(func(chain *Chain, engine *engine.Engine) (shutdown func()) {
+			return lo.Batch(
+				engine.Events.BlockRequester.Tick.Hook(b.SendRequest).Unhook,
+				engine.Events.Scheduler.BlockScheduled.Hook(func(block *blocks.Block) { b.SendResponse(block.ModelBlock()) }).Unhook,
+				engine.Events.Scheduler.BlockSkipped.Hook(func(block *blocks.Block) { b.SendResponse(block.ModelBlock()) }).Unhook,
+			)
 		})
 	})