Move commitment checks to block's syntactical check.

api_protocol_parameters.go

@@ -48,8 +48,10 @@ type basicProtocolParameters struct {
 	// and commitments in its past-cone to ATT and lastCommittedSlot respectively.
 	LivenessThreshold SlotIndex `serix:"16,mapKey=livenessThreshold"`
 	// MinCommittableAge is the minimum age relative to the accepted tangle time slot index that a slot can be committed.
+	// For example, if the last accepted slot is in slot 100, and minCommittableAge=10, then the latest committed slot can be at most 100-10=90.
 	MinCommittableAge SlotIndex `serix:"17,mapKey=minCommittableAge"`
 	// MaxCommittableAge is the maximum age for a slot commitment to be included in a block relative to the slot index of the block issuing time.
+	// For example, if the last accepted slot is in slot 100, and maxCommittableAge=20, then the oldest referencable commitment is 100-20=80.
 	MaxCommittableAge SlotIndex `serix:"18,mapKey=maxCommittableAge"`
 	// EpochNearingThreshold is used by the epoch orchestrator to detect the slot that should trigger a new committee
 	// selection for the next and upcoming epoch.

api_v3.go

@@ -6,7 +6,6 @@ import (
 	"time"
 
 	"github.com/iotaledger/hive.go/ierrors"
-	"github.com/iotaledger/hive.go/lo"
 	"github.com/iotaledger/hive.go/serializer/v2"
 	"github.com/iotaledger/hive.go/serializer/v2/serix"
 )
@@ -494,11 +493,6 @@ func V3API(protoParams ProtocolParameters) API {
 			serix.TypeSettings{}.WithLengthPrefixType(serix.LengthPrefixTypeAsUint16).WithArrayRules(txV3UnlocksArrRules),
 		))
 		must(api.RegisterValidators(Transaction{}, nil, func(ctx context.Context, tx Transaction) error {
-			// limit unlock block count = input count
-			if len(tx.Unlocks) != len(tx.Essence.Inputs) {
-				return ierrors.Errorf("unlock block count must match inputs in essence, %d vs. %d", len(tx.Unlocks), len(tx.Essence.Inputs))
-			}
-
 			return tx.syntacticallyValidate(v3)
 		}))
 		must(api.RegisterInterfaceObjects((*TxEssencePayload)(nil), (*TaggedData)(nil)))
@@ -537,31 +531,7 @@ func V3API(protoParams ProtocolParameters) API {
 
 			return nil
 		}, func(ctx context.Context, protocolBlock ProtocolBlock) error {
-			if protoParams.Version() != protocolBlock.ProtocolVersion {
-				return ierrors.Errorf("mismatched protocol version: wanted %d, got %d in block", protoParams.Version(), protocolBlock.ProtocolVersion)
-			}
-
-			block := protocolBlock.Block
-			if len(block.WeakParentIDs()) > 0 {
-				// weak parents must be disjunct to the rest of the parents
-				nonWeakParents := lo.KeyOnlyBy(append(block.StrongParentIDs(), block.ShallowLikeParentIDs()...), func(v BlockID) BlockID {
-					return v
-				})
-
-				for _, parent := range block.WeakParentIDs() {
-					if _, contains := nonWeakParents[parent]; contains {
-						return ierrors.Errorf("weak parents must be disjunct to the rest of the parents")
-					}
-				}
-			}
-
-			if validationBlock, ok := block.(*ValidationBlock); ok {
-				if validationBlock.HighestSupportedVersion < protocolBlock.ProtocolVersion {
-					return ierrors.Errorf("highest supported version %d must be greater equal protocol version %d", validationBlock.HighestSupportedVersion, protocolBlock.ProtocolVersion)
-				}
-			}
-
-			return nil
+			return protocolBlock.syntacticallyValidate(v3)
 		}))
 	}
 

block.go

@@ -11,6 +11,7 @@ import (
 
 	hiveEd25519 "github.com/iotaledger/hive.go/crypto/ed25519"
 	"github.com/iotaledger/hive.go/ierrors"
+	"github.com/iotaledger/hive.go/lo"
 	"github.com/iotaledger/hive.go/serializer/v2"
 	"github.com/iotaledger/hive.go/serializer/v2/byteutils"
 	"github.com/iotaledger/iota.go/v4/hexutil"
@@ -27,6 +28,16 @@ const (
 	BlockTypeValidationMaxParents = BlockMaxParents + 42
 )
 
+var (
+	ErrWeakParentsInvalid                 = ierrors.New("weak parents must be disjunct to the rest of the parents")
+	ErrCommitmentTooOld                   = ierrors.New("a block cannot commit to a slot that is older than the block's slot minus maxCommittableAge")
+	ErrCommitmentTooRecent                = ierrors.New("a block cannot commit to a slot that is more recent than the block's slot minus minCommittableAge")
+	ErrCommitmentInputTooOld              = ierrors.New("a block cannot contain a commitment input with index older than the block's slot minus maxCommittableAge")
+	ErrCommitmentInputTooRecent           = ierrors.New("a block cannot contain a commitment input with index more recent than the block's slot minus minCommittableAge")
+	ErrInvalidBlockVersion                = ierrors.New("block has invalid protocol version")
+	ErrCommitmentInputNewerThanCommitment = ierrors.New("a block cannot contain a commitment input with index newer than the commitment index")
+)
+
 // BlockType denotes a type of Block.
 type BlockType byte
 
@@ -286,6 +297,49 @@ func (b *ProtocolBlock) WorkScore(workScoreStructure *WorkScoreStructure) (WorkS
 	return workScoreHeader.Add(workScoreBlock, workScoreSignature)
 }
 
+// syntacticallyValidate syntactically validates the ProtocolBlock.
+func (b *ProtocolBlock) syntacticallyValidate(api API) error {
+	if api.ProtocolParameters().Version() != b.ProtocolVersion {
+		return ierrors.Wrapf(ErrInvalidBlockVersion, "mismatched protocol version: wanted %d, got %d in block", api.ProtocolParameters().Version(), b.ProtocolVersion)
+	}
+
+	block := b.Block
+	if len(block.WeakParentIDs()) > 0 {
+		// weak parents must be disjunct to the rest of the parents
+		nonWeakParents := lo.KeyOnlyBy(append(block.StrongParentIDs(), block.ShallowLikeParentIDs()...), func(v BlockID) BlockID {
+			return v
+		})
+
+		for _, parent := range block.WeakParentIDs() {
+			if _, contains := nonWeakParents[parent]; contains {
+				return ierrors.Wrapf(ErrWeakParentsInvalid, "weak parents (%s) cannot have common elements with strong parents (%s) or shallow likes (%s)", block.WeakParentIDs(), block.StrongParentIDs(), block.ShallowLikeParentIDs())
+			}
+		}
+	}
+
+	minCommittableAge := api.ProtocolParameters().MinCommittableAge()
+	maxCommittableAge := api.ProtocolParameters().MaxCommittableAge()
+	commitmentIndex := b.SlotCommitmentID.Index()
+	blockID, err := b.ID(api)
+	if err != nil {
+		return ierrors.Wrapf(err, "failed to syntactically validate block")
+	}
+	blockIndex := blockID.Index()
+
+	// check that commitment is not too recent.
+	if commitmentIndex > 0 && // Don't filter commitments to genesis based on being too recent.
+		blockIndex < commitmentIndex+minCommittableAge {
+		return ierrors.Wrapf(ErrCommitmentTooRecent, "block at slot %d committing to slot %d", blockIndex, b.SlotCommitmentID.Index())
+	}
+
+	// Check that commitment is not too old.
+	if blockIndex > commitmentIndex+maxCommittableAge {
+		return ierrors.Wrapf(ErrCommitmentTooOld, "block at slot %d committing to slot %d, max committable age %d", blockIndex, b.SlotCommitmentID.Index(), maxCommittableAge)
+	}
+
+	return b.Block.syntacticallyValidate(api, b)
+}
+
 type Block interface {
 	Type() BlockType
 
@@ -295,6 +349,8 @@ type Block interface {
 
 	Hash(api API) (Identifier, error)
 
+	syntacticallyValidate(api API, protocolBlock *ProtocolBlock) error
+
 	ProcessableObject
 }
 
@@ -361,6 +417,42 @@ func (b *BasicBlock) WorkScore(workScoreStructure *WorkScoreStructure) (WorkScor
 	return workScoreBytes.Add(workScoreMissingParents, workScorePayload)
 }
 
+// syntacticallyValidate syntactically validates the BasicBlock.
+func (b *BasicBlock) syntacticallyValidate(api API, protocolBlock *ProtocolBlock) error {
+	if b.Payload != nil && b.Payload.PayloadType() == PayloadTransaction {
+		blockID, err := protocolBlock.ID(api)
+		if err != nil {
+			// TODO: wrap error
+			return err
+		}
+		blockIndex := blockID.Index()
+
+		minCommittableAge := api.ProtocolParameters().MinCommittableAge()
+		maxCommittableAge := api.ProtocolParameters().MaxCommittableAge()
+
+		tx, _ := b.Payload.(*Transaction)
+		if cInput := tx.CommitmentInput(); cInput != nil {
+			cInputIndex := cInput.CommitmentID.Index()
+			// check that commitment input is not too recent.
+			if cInputIndex > 0 && // Don't filter commitments to genesis based on being too recent.
+				blockIndex < cInputIndex+minCommittableAge { // filter commitments to future slots.
+				return ierrors.Wrapf(ErrCommitmentInputTooRecent, "block at slot %d with commitment input to slot %d", blockIndex, cInput.CommitmentID.Index())
+			}
+			// Check that commitment input is not too old.
+			if blockIndex > cInputIndex+maxCommittableAge {
+				return ierrors.Wrapf(ErrCommitmentInputTooOld, "block at slot %d committing to slot %d, max committable age %d", blockIndex, cInput.CommitmentID.Index(), maxCommittableAge)
+			}
+
+			if cInputIndex > protocolBlock.SlotCommitmentID.Index() {
+				return ierrors.Wrapf(ErrCommitmentInputNewerThanCommitment, "transaction in a block contains CommitmentInput to slot %d while max allowed is %d", cInput.CommitmentID.Index(), protocolBlock.SlotCommitmentID.Index())
+			}
+
+		}
+	}
+
+	return nil
+}
+
 // ValidationBlock represents a validation vertex in the Tangle/BlockDAG.
 type ValidationBlock struct {
 	// The parents the block references.
@@ -403,6 +495,15 @@ func (b *ValidationBlock) WorkScore(_ *WorkScoreStructure) (WorkScore, error) {
 	return 0, nil
 }
 
+// syntacticallyValidate syntactically validates the ValidationBlock.
+func (b *ValidationBlock) syntacticallyValidate(_ API, protocolBlock *ProtocolBlock) error {
+	if b.HighestSupportedVersion < protocolBlock.ProtocolVersion {
+		return ierrors.Errorf("highest supported version %d must be greater equal protocol version %d", b.HighestSupportedVersion, protocolBlock.ProtocolVersion)
+	}
+
+	return nil
+}
+
 // ParentsType is a type that defines the type of the parent.
 type ParentsType uint8