implement process_withdrawals

beacon-chain/core/blocks/BUILD.bazel

@@ -45,6 +45,7 @@ go_library(
         "//encoding/bytesutil:go_default_library",
         "//math:go_default_library",
         "//network/forks:go_default_library",
+        "//proto/engine/v1:go_default_library",
         "//proto/prysm/v1alpha1:go_default_library",
         "//proto/prysm/v1alpha1/attestation:go_default_library",
         "//proto/prysm/v1alpha1/slashings:go_default_library",

beacon-chain/core/blocks/error.go

@@ -6,3 +6,8 @@ var errNilSignedWithdrawalMessage = errors.New("nil SignedBLSToExecutionChange m
 var errNilWithdrawalMessage = errors.New("nil BLSToExecutionChange message")
 var errInvalidBLSPrefix = errors.New("withdrawal credential prefix is not a BLS prefix")
 var errInvalidWithdrawalCredentials = errors.New("withdrawal credentials do not match")
+var errInvalidWithdrawalIndex = errors.New("invalid withdrawal index")
+var errInvalidValidatorIndex = errors.New("invalid validator index")
+var errInvalidWithdrawalAmount = errors.New("invalid withdrawal amount")
+var errInvalidExecutionAddress = errors.New("invalid execution address")
+var errInvalidWithdrawalNumber = errors.New("invalid number of withdrawals")

beacon-chain/core/blocks/withdrawals.go

@@ -3,11 +3,14 @@ package blocks
 import (
 	"bytes"
 
+	"github.com/pkg/errors"
+	"github.com/prysmaticlabs/prysm/v3/beacon-chain/core/helpers"
 	"github.com/prysmaticlabs/prysm/v3/beacon-chain/core/signing"
 	"github.com/prysmaticlabs/prysm/v3/beacon-chain/state"
 	"github.com/prysmaticlabs/prysm/v3/config/params"
 	"github.com/prysmaticlabs/prysm/v3/crypto/hash/htr"
 	"github.com/prysmaticlabs/prysm/v3/encoding/bytesutil"
+	enginev1 "github.com/prysmaticlabs/prysm/v3/proto/engine/v1"
 	ethpb "github.com/prysmaticlabs/prysm/v3/proto/prysm/v1alpha1"
 	"github.com/prysmaticlabs/prysm/v3/time/slots"
 )
@@ -76,3 +79,40 @@ func ProcessBLSToExecutionChange(st state.BeaconState, signed *ethpb.SignedBLSTo
 	err = st.UpdateValidatorAtIndex(message.ValidatorIndex, val)
 	return st, err
 }
+
+func ProcessWithdrawals(st state.BeaconState, withdrawals []*enginev1.Withdrawal) (state.BeaconState, error) {
+	expected, err := st.ExpectedWithdrawals()
+	if err != nil {
+		return nil, errors.Wrap(err, "could not get expected withdrawals")
+	}
+	if len(expected) != len(withdrawals) {
+		return nil, errInvalidWithdrawalNumber
+	}
+	for i, withdrawal := range withdrawals {
+		if withdrawal.WithdrawalIndex != expected[i].WithdrawalIndex {
+			return nil, errInvalidWithdrawalIndex
+		}
+		if withdrawal.ValidatorIndex != expected[i].ValidatorIndex {
+			return nil, errInvalidValidatorIndex
+		}
+		if !bytes.Equal(withdrawal.ExecutionAddress, expected[i].ExecutionAddress) {
+			return nil, errInvalidExecutionAddress
+		}
+		if withdrawal.Amount != expected[i].Amount {
+			return nil, errInvalidWithdrawalAmount
+		}
+		err := helpers.DecreaseBalance(st, withdrawal.ValidatorIndex, withdrawal.Amount)
+		if err != nil {
+			return nil, errors.Wrap(err, "could not decrease balance")
+		}
+	}
+	if len(withdrawals) > 0 {
+		if err := st.SetNextWithdrawalIndex(withdrawals[len(withdrawals)-1].WithdrawalIndex + 1); err != nil {
+			return nil, errors.Wrap(err, "could not set withdrawal index")
+		}
+		if err := st.SetLastWithdrawalValidatorIndex(withdrawals[len(withdrawals)-1].ValidatorIndex); err != nil {
+			return nil, errors.Wrap(err, "could not set latest withdrawal validator index")
+		}
+	}
+	return st, nil
+}