eth/catalyst: add Engine API stubs for Amsterdam fork

Add Engine API method stubs for the Amsterdam fork (Gloas on CL side):
- engine_newPayloadV5 for Amsterdam payloads
- engine_getPayloadV6 for Amsterdam payloads
- engine_newPayloadWithWitnessV5 for witness generation
- engine_executeStatelessPayloadV5 for stateless execution
- Update engine_forkchoiceUpdatedV3 to accept Amsterdam payloads
- Add PayloadV4 constant for ExecutionPayloadV4

This is a minimal implementation with method stubs only - no blockAccessList
(EIP-7928) integration yet.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

beacon/engine/types.go

@@ -50,6 +50,13 @@ var (
 	// ExecutionPayloadV3 has the syntax of ExecutionPayloadV2 and appends the new
 	// fields: blobGasUsed and excessBlobGas.
 	PayloadV3 PayloadVersion = 0x3
+
+	// PayloadV4 is the identifier of ExecutionPayloadV4 introduced in amsterdam fork.
+	//
+	// https://github.com/ethereum/execution-apis/blob/main/src/engine/amsterdam.md#executionpayloadv4
+	// ExecutionPayloadV4 has the syntax of ExecutionPayloadV3 and appends the new
+	// field: blockAccessList (EIP-7928).
+	PayloadV4 PayloadVersion = 0x4
 )
 
 //go:generate go run github.com/fjl/gencodec -type PayloadAttributes -field-override payloadAttributesMarshaling -out gen_blockparams.go

eth/catalyst/api.go

@@ -198,8 +198,8 @@ func (api *ConsensusAPI) ForkchoiceUpdatedV3(update engine.ForkchoiceStateV1, pa
 			return engine.STATUS_INVALID, attributesErr("missing withdrawals")
 		case params.BeaconRoot == nil:
 			return engine.STATUS_INVALID, attributesErr("missing beacon root")
-		case !api.checkFork(params.Timestamp, forks.Cancun, forks.Prague, forks.Osaka, forks.BPO1, forks.BPO2, forks.BPO3, forks.BPO4, forks.BPO5):
+		case !api.checkFork(params.Timestamp, forks.Cancun, forks.Prague, forks.Osaka, forks.BPO1, forks.Amsterdam, forks.BPO2, forks.BPO3, forks.BPO4, forks.BPO5):
-			return engine.STATUS_INVALID, unsupportedForkErr("fcuV3 must only be called for cancun/prague/osaka payloads")
+			return engine.STATUS_INVALID, unsupportedForkErr("fcuV3 must only be called for cancun/prague/osaka/amsterdam payloads")
 		}
 	}
 	// TODO(matt): the spec requires that fcu is applied when called on a valid
@@ -452,9 +452,24 @@ func (api *ConsensusAPI) GetPayloadV5(payloadID engine.PayloadID) (*engine.Execu
 			forks.BPO3,
 			forks.BPO4,
 			forks.BPO5,
+			// Amsterdam uses GetPayloadV6
 		})
 }
 
+// GetPayloadV6 returns a cached payload by id. This endpoint should only
+// be used after the Amsterdam fork.
+//
+// This method follows the same specification as engine_getPayloadV5 with
+// changes of returning ExecutionPayloadV4 with blockAccessList.
+func (api *ConsensusAPI) GetPayloadV6(payloadID engine.PayloadID) (*engine.ExecutionPayloadEnvelope, error) {
+	return api.getPayload(
+		payloadID,
+		false,
+		[]engine.PayloadVersion{engine.PayloadV4},
+		[]forks.Fork{forks.Amsterdam},
+	)
+}
+
 // getPayload will retrieve the specified payload and verify it conforms to the
 // endpoint's allowed payload versions and forks.
 //
@@ -687,6 +702,8 @@ func (api *ConsensusAPI) NewPayloadV4(params engine.ExecutableData, versionedHas
 		return invalidStatus, paramsErr("nil beaconRoot post-cancun")
 	case executionRequests == nil:
 		return invalidStatus, paramsErr("nil executionRequests post-prague")
+	case api.checkFork(params.Timestamp, forks.Amsterdam):
+		return invalidStatus, unsupportedForkErr("newPayloadV4 must not be called for amsterdam payloads, use newPayloadV5")
 	case !api.checkFork(params.Timestamp, forks.Prague, forks.Osaka, forks.BPO1, forks.BPO2, forks.BPO3, forks.BPO4, forks.BPO5):
 		return invalidStatus, unsupportedForkErr("newPayloadV4 must only be called for prague/osaka payloads")
 	}
@@ -697,6 +714,32 @@ func (api *ConsensusAPI) NewPayloadV4(params engine.ExecutableData, versionedHas
 	return api.newPayload(params, versionedHashes, beaconRoot, requests, false)
 }
 
+// NewPayloadV5 creates an Eth1 block, inserts it in the chain, and returns the status of the chain.
+// This endpoint should be used for the Amsterdam fork.
+func (api *ConsensusAPI) NewPayloadV5(params engine.ExecutableData, versionedHashes []common.Hash, beaconRoot *common.Hash, executionRequests []hexutil.Bytes) (engine.PayloadStatusV1, error) {
+	switch {
+	case params.Withdrawals == nil:
+		return invalidStatus, paramsErr("nil withdrawals post-shanghai")
+	case params.ExcessBlobGas == nil:
+		return invalidStatus, paramsErr("nil excessBlobGas post-cancun")
+	case params.BlobGasUsed == nil:
+		return invalidStatus, paramsErr("nil blobGasUsed post-cancun")
+	case versionedHashes == nil:
+		return invalidStatus, paramsErr("nil versionedHashes post-cancun")
+	case beaconRoot == nil:
+		return invalidStatus, paramsErr("nil beaconRoot post-cancun")
+	case executionRequests == nil:
+		return invalidStatus, paramsErr("nil executionRequests post-prague")
+	case !api.checkFork(params.Timestamp, forks.Amsterdam):
+		return invalidStatus, unsupportedForkErr("newPayloadV5 must only be called for amsterdam payloads")
+	}
+	requests := convertRequests(executionRequests)
+	if err := validateRequests(requests); err != nil {
+		return engine.PayloadStatusV1{Status: engine.INVALID}, engine.InvalidParams.With(err)
+	}
+	return api.newPayload(params, versionedHashes, beaconRoot, requests, false)
+}
+
 func (api *ConsensusAPI) newPayload(params engine.ExecutableData, versionedHashes []common.Hash, beaconRoot *common.Hash, requests [][]byte, witness bool) (engine.PayloadStatusV1, error) {
 	// The locking here is, strictly, not required. Without these locks, this can happen:
 	//

eth/catalyst/witness.go

@@ -73,8 +73,8 @@ func (api *ConsensusAPI) ForkchoiceUpdatedWithWitnessV3(update engine.Forkchoice
 			return engine.STATUS_INVALID, attributesErr("missing withdrawals")
 		case params.BeaconRoot == nil:
 			return engine.STATUS_INVALID, attributesErr("missing beacon root")
-		case !api.checkFork(params.Timestamp, forks.Cancun, forks.Prague, forks.Osaka, forks.BPO1, forks.BPO2, forks.BPO3, forks.BPO4, forks.BPO5):
+		case !api.checkFork(params.Timestamp, forks.Cancun, forks.Prague, forks.Osaka, forks.BPO1, forks.Amsterdam, forks.BPO2, forks.BPO3, forks.BPO4, forks.BPO5):
-			return engine.STATUS_INVALID, unsupportedForkErr("fcuV3 must only be called for cancun/prague/osaka payloads")
+			return engine.STATUS_INVALID, unsupportedForkErr("fcuV3 must only be called for cancun/prague/osaka/amsterdam payloads")
 		}
 	}
 	// TODO(matt): the spec requires that fcu is applied when called on a valid
@@ -161,6 +161,32 @@ func (api *ConsensusAPI) NewPayloadWithWitnessV4(params engine.ExecutableData, v
 	return api.newPayload(params, versionedHashes, beaconRoot, requests, true)
 }
 
+// NewPayloadWithWitnessV5 is analogous to NewPayloadV5, only it also generates
+// and returns a stateless witness after running the payload.
+func (api *ConsensusAPI) NewPayloadWithWitnessV5(params engine.ExecutableData, versionedHashes []common.Hash, beaconRoot *common.Hash, executionRequests []hexutil.Bytes) (engine.PayloadStatusV1, error) {
+	switch {
+	case params.Withdrawals == nil:
+		return invalidStatus, paramsErr("nil withdrawals post-shanghai")
+	case params.ExcessBlobGas == nil:
+		return invalidStatus, paramsErr("nil excessBlobGas post-cancun")
+	case params.BlobGasUsed == nil:
+		return invalidStatus, paramsErr("nil blobGasUsed post-cancun")
+	case versionedHashes == nil:
+		return invalidStatus, paramsErr("nil versionedHashes post-cancun")
+	case beaconRoot == nil:
+		return invalidStatus, paramsErr("nil beaconRoot post-cancun")
+	case executionRequests == nil:
+		return invalidStatus, paramsErr("nil executionRequests post-prague")
+	case !api.checkFork(params.Timestamp, forks.Amsterdam):
+		return invalidStatus, unsupportedForkErr("newPayloadWithWitnessV5 must only be called for amsterdam payloads")
+	}
+	requests := convertRequests(executionRequests)
+	if err := validateRequests(requests); err != nil {
+		return engine.PayloadStatusV1{Status: engine.INVALID}, engine.InvalidParams.With(err)
+	}
+	return api.newPayload(params, versionedHashes, beaconRoot, requests, true)
+}
+
 // ExecuteStatelessPayloadV1 is analogous to NewPayloadV1, only it operates in
 // a stateless mode on top of a provided witness instead of the local database.
 func (api *ConsensusAPI) ExecuteStatelessPayloadV1(params engine.ExecutableData, opaqueWitness hexutil.Bytes) (engine.StatelessPayloadStatusV1, error) {
@@ -238,6 +264,32 @@ func (api *ConsensusAPI) ExecuteStatelessPayloadV4(params engine.ExecutableData,
 	return api.executeStatelessPayload(params, versionedHashes, beaconRoot, requests, opaqueWitness)
 }
 
+// ExecuteStatelessPayloadV5 is analogous to NewPayloadV5, only it operates in
+// a stateless mode on top of a provided witness instead of the local database.
+func (api *ConsensusAPI) ExecuteStatelessPayloadV5(params engine.ExecutableData, versionedHashes []common.Hash, beaconRoot *common.Hash, executionRequests []hexutil.Bytes, opaqueWitness hexutil.Bytes) (engine.StatelessPayloadStatusV1, error) {
+	switch {
+	case params.Withdrawals == nil:
+		return engine.StatelessPayloadStatusV1{Status: engine.INVALID}, paramsErr("nil withdrawals post-shanghai")
+	case params.ExcessBlobGas == nil:
+		return engine.StatelessPayloadStatusV1{Status: engine.INVALID}, paramsErr("nil excessBlobGas post-cancun")
+	case params.BlobGasUsed == nil:
+		return engine.StatelessPayloadStatusV1{Status: engine.INVALID}, paramsErr("nil blobGasUsed post-cancun")
+	case versionedHashes == nil:
+		return engine.StatelessPayloadStatusV1{Status: engine.INVALID}, paramsErr("nil versionedHashes post-cancun")
+	case beaconRoot == nil:
+		return engine.StatelessPayloadStatusV1{Status: engine.INVALID}, paramsErr("nil beaconRoot post-cancun")
+	case executionRequests == nil:
+		return engine.StatelessPayloadStatusV1{Status: engine.INVALID}, paramsErr("nil executionRequests post-prague")
+	case !api.checkFork(params.Timestamp, forks.Amsterdam):
+		return engine.StatelessPayloadStatusV1{Status: engine.INVALID}, unsupportedForkErr("executeStatelessPayloadV5 must only be called for amsterdam payloads")
+	}
+	requests := convertRequests(executionRequests)
+	if err := validateRequests(requests); err != nil {
+		return engine.StatelessPayloadStatusV1{Status: engine.INVALID}, engine.InvalidParams.With(err)
+	}
+	return api.executeStatelessPayload(params, versionedHashes, beaconRoot, requests, opaqueWitness)
+}
+
 func (api *ConsensusAPI) executeStatelessPayload(params engine.ExecutableData, versionedHashes []common.Hash, beaconRoot *common.Hash, requests [][]byte, opaqueWitness hexutil.Bytes) (engine.StatelessPayloadStatusV1, error) {
 	log.Trace("Engine API request received", "method", "ExecuteStatelessPayload", "number", params.Number, "hash", params.BlockHash)
 	block, err := engine.ExecutableDataToBlockNoHash(params, versionedHashes, beaconRoot, requests)