Implement EIP-8045: exclude slashed validators from proposer lookahead. (#16857)

Adds a gloas-specific ProcessProposerLookahead that filters out slashed
validators from the candidate set when populating the EIP-7917 proposer
lookahead, leaving the fulu path unchanged.

---------

Co-authored-by: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Co-authored-by: james-prysm <90280386+james-prysm@users.noreply.github.com>

Author: 3 people

.ethspecify.yml

@@ -1,4 +1,4 @@
-version: v1.7.0-alpha.8
+version: v1.7.0-alpha.10
 style: full
 
 specrefs:
@@ -35,6 +35,7 @@ exceptions:
     # altair
     - PARTICIPATION_FLAG_WEIGHTS#altair
     # bellatrix
+    - EMPTY_BLOCK_HASH#bellatrix
     - PAYLOAD_STATUS_INVALIDATED#bellatrix
     - PAYLOAD_STATUS_NOT_VALIDATED#bellatrix
     - PAYLOAD_STATUS_VALID#bellatrix
@@ -122,7 +123,6 @@ exceptions:
     - ExecutionPayload#gloas
     - ExecutionPayloadBid#gloas
     - ExecutionPayloadEnvelope#gloas
-    - ForkChoiceNode#gloas
     - IndexedPayloadAttestation#gloas
     - LightClientHeader#gloas
     - PartialDataColumnGroupID#gloas
@@ -138,6 +138,7 @@ exceptions:
   dataclasses:
     # phase0
     - FastConfirmationStore#phase0
+    - ForkChoiceNode#phase0
     - LatestMessage#phase0
     - Seen#phase0
     - Store#phase0
@@ -157,10 +158,13 @@ exceptions:
     - Seen#electra
     # fulu
     - BlobParameters#fulu
+    - Seen#fulu
     # gloas
     - ExpectedWithdrawals#gloas
+    - ForkChoiceNode#gloas
     - LatestMessage#gloas
     - PayloadAttributes#gloas
+    - Seen#gloas
     - Store#gloas
     # heze
     - GetInclusionListResponse#heze
@@ -240,14 +244,18 @@ exceptions:
     - get_current_balance_source#phase0
     - get_current_target#phase0
     - get_current_target_score#phase0
+    - get_dependent_root#phase0
     - get_equivocation_score#phase0
     - get_fast_confirmation_store#phase0
     - get_latest_confirmed#phase0
     - get_latest_message_epoch#phase0
+    - get_node_children#phase0
+    - get_node_for_root#phase0
     - get_previous_balance_source#phase0
     - get_pulled_up_head_state#phase0
     - get_slot_committee#phase0
     - get_support_discount#phase0
+    - get_supported_node#phase0
     - is_ancestor#phase0
     - is_confirmed_chain_safe#phase0
     - is_full_validator_set_covered#phase0
@@ -347,6 +355,7 @@ exceptions:
     - validate_sync_committee_message_gossip#altair
     # bellatrix
     - get_execution_payload#bellatrix
+    - get_safe_execution_block_hash#bellatrix
     - is_merge_transition_block#bellatrix
     - is_optimistic_candidate_block#bellatrix
     - latest_verified_ancestor#bellatrix
@@ -421,6 +430,13 @@ exceptions:
     - get_data_column_sidecars_from_block#fulu
     - get_data_column_sidecars_from_column_sidecar#fulu
     - recover_matrix#fulu
+    - process_block#fulu
+    - process_deposit_request#fulu
+    - process_operations#fulu
+    - process_pending_deposits#fulu
+    - validate_beacon_block_gossip#fulu
+    - validate_data_column_sidecar_gossip#fulu
+    - validate_partial_data_column_sidecar_gossip#fulu
     # gloas
     - get_latest_message_epoch#gloas
     - get_payload_due_ms#gloas
@@ -454,9 +470,15 @@ exceptions:
     - get_forkchoice_store#gloas
     - get_head#gloas
     - get_indexed_payload_attestation#gloas
+    - get_dependent_root#gloas
     - get_next_sync_committee_indices#gloas
     - get_node_children#gloas
+    - get_node_for_root#gloas
     - get_parent_payload_status#gloas
+    - get_safe_execution_block_hash#gloas
+    - get_supported_node#gloas
+    - is_ancestor#gloas
+    - is_previous_slot_payload_decision#gloas
     - get_payload_attestation_due_ms#gloas
     - get_payload_attestation_message_signature#gloas
     - get_payload_status_tiebreaker#gloas
@@ -470,7 +492,6 @@ exceptions:
     - is_builder_withdrawal_credential#gloas
     - is_merge_transition_complete#gloas
     - is_parent_node_full#gloas
-    - is_supporting_vote#gloas
     - is_valid_indexed_payload_attestation#gloas
     - notify_ptc_messages#gloas
     - on_block#gloas

WORKSPACE

@@ -273,16 +273,16 @@ filegroup(
     url = "https://github.com/ethereum/EIPs/archive/5480440fe51742ed23342b68cf106cefd427e39d.tar.gz",
 )
 
-consensus_spec_version = "v1.7.0-alpha.8"
+consensus_spec_version = "v1.7.0-alpha.10"
 
 load("@prysm//tools:download_spectests.bzl", "consensus_spec_tests")
 
 consensus_spec_tests(
     name = "consensus_spec_tests",
     flavors = {
         "general": "sha256-szDpBVO2Ebi8/bwbiWFpW6H4c5gxnpU3hAUS31AF02E=",
-        "minimal": "sha256-SBEdtQ+HwaxFCuPwzcvkJazRuur6LlMol3egANCwH4Y=",
-        "mainnet": "sha256-alrKgbLxWFRNb8/jLInQ0eJru5ScAWnxM0rEOzdm/YE=",
+        "minimal": "sha256-WUEeO8e2eyl8vvN/oFvmr3gnBbLeJHtcctfxqtH0DZg=",
+        "mainnet": "sha256-F8jPmN/5cnKlCJvrGa90yWFE7NlQNl8dViehMcLc7GY=",
     },
     version = consensus_spec_version,
 )
@@ -298,7 +298,7 @@ filegroup(
     visibility = ["//visibility:public"],
 )
     """,
-    integrity = "sha256-x0OkYCK+MJfPoEAnEmpftgl60ervC4W3zCg0KA9XiXU=",
+    integrity = "sha256-a3naXiY2eXKGLBoAPetHfgKq98/vO6SI1xueoNCZnYQ=",
     strip_prefix = "consensus-specs-" + consensus_spec_version[1:],
     url = "https://github.com/ethereum/consensus-specs/archive/refs/tags/%s.tar.gz" % consensus_spec_version,
 )

beacon-chain/core/gloas/BUILD.bazel

@@ -13,6 +13,7 @@ go_library(
         "payload.go",
         "payload_attestation.go",
         "pending_payment.go",
+        "proposer_lookahead.go",
         "proposer_slashing.go",
         "upgrade.go",
         "withdrawals.go",
@@ -57,6 +58,7 @@ go_test(
         "payload_attestation_test.go",
         "payload_test.go",
         "pending_payment_test.go",
+        "proposer_lookahead_test.go",
         "proposer_slashing_test.go",
         "upgrade_test.go",
         "withdrawals_test.go",

beacon-chain/core/gloas/payload_attestation.go

@@ -280,7 +280,7 @@ func selectByBalanceFill(
 
 // validIndexedPayloadAttestation verifies the signature of an indexed payload attestation.
 //
-//	<spec fn="is_valid_indexed_payload_attestation" fork="gloas" hash="d76e0f89">
+//	<spec fn="is_valid_indexed_payload_attestation" fork="gloas" hash="745c04a1">
 //	def is_valid_indexed_payload_attestation(
 //	    state: BeaconState, attestation: IndexedPayloadAttestation
 //	) -> bool:
@@ -290,7 +290,7 @@ func selectByBalanceFill(
 //	    """
 //	    # Verify indices are non-empty and sorted
 //	    indices = attestation.attesting_indices
-//	    if len(indices) == 0 or not indices == sorted(indices):
+//	    if len(indices) == 0 or indices != sorted(indices):
 //	        return False
 //
 //	    # Verify aggregate signature

beacon-chain/core/gloas/proposer_lookahead.go

@@ -0,0 +1,42 @@
+package gloas
+
+import (
+	"context"
+
+	"github.com/OffchainLabs/prysm/v7/beacon-chain/core/helpers"
+	"github.com/OffchainLabs/prysm/v7/beacon-chain/state"
+	"github.com/OffchainLabs/prysm/v7/config/params"
+	"github.com/OffchainLabs/prysm/v7/monitoring/tracing/trace"
+	"github.com/OffchainLabs/prysm/v7/time/slots"
+	"github.com/pkg/errors"
+)
+
+// ProcessProposerLookahead advances the cached proposer lookahead by one epoch
+// using EIP-8045 semantics: slashed validators are excluded from the candidate
+// pool used to derive the new last-epoch proposer indices.
+func ProcessProposerLookahead(ctx context.Context, state state.BeaconState) error {
+	_, span := trace.StartSpan(ctx, "gloas.processProposerLookahead")
+	defer span.End()
+
+	if state == nil || state.IsNil() {
+		return errors.New("nil state")
+	}
+
+	lookAhead, err := state.ProposerLookahead()
+	if err != nil {
+		return errors.Wrap(err, "could not get proposer lookahead")
+	}
+	lastEpochStart := len(lookAhead) - int(params.BeaconConfig().SlotsPerEpoch)
+	copy(lookAhead[:lastEpochStart], lookAhead[params.BeaconConfig().SlotsPerEpoch:])
+	lastEpoch := slots.ToEpoch(state.Slot()).AddEpoch(params.BeaconConfig().MinSeedLookahead).Add(1)
+	indices, err := helpers.ActiveNonSlashedValidatorIndices(ctx, state, lastEpoch)
+	if err != nil {
+		return err
+	}
+	lastEpochProposers, err := helpers.PrecomputeProposerIndices(state, indices, lastEpoch)
+	if err != nil {
+		return errors.Wrap(err, "could not precompute proposer indices")
+	}
+	copy(lookAhead[lastEpochStart:], lastEpochProposers)
+	return state.SetProposerLookahead(lookAhead)
+}

beacon-chain/core/gloas/proposer_lookahead_test.go

@@ -0,0 +1,47 @@
+package gloas_test
+
+import (
+	"testing"
+
+	"github.com/OffchainLabs/prysm/v7/beacon-chain/core/gloas"
+	"github.com/OffchainLabs/prysm/v7/config/params"
+	"github.com/OffchainLabs/prysm/v7/testing/require"
+	"github.com/OffchainLabs/prysm/v7/testing/util"
+)
+
+// Verifies the EIP-8045 filter: any validator marked slashed when the last
+// lookahead epoch is computed must not appear in that epoch's proposer slots.
+func TestProcessProposerLookahead_ExcludesSlashedValidators(t *testing.T) {
+	ctx := t.Context()
+
+	st, _ := util.DeterministicGenesisStateGloas(t, 256)
+
+	slotsPerEpoch := uint64(params.BeaconConfig().SlotsPerEpoch)
+	lookaheadSize := (uint64(params.BeaconConfig().MinSeedLookahead) + 1) * slotsPerEpoch
+	lastEpochStart := lookaheadSize - slotsPerEpoch
+
+	// Baseline: take the unfiltered last-epoch lookahead so we can pick a
+	// validator that is guaranteed to be selected, then verify the filtered
+	// version drops it.
+	baseline := st.Copy()
+	require.NoError(t, gloas.ProcessProposerLookahead(ctx, baseline))
+	baseLookahead, err := baseline.ProposerLookahead()
+	require.NoError(t, err)
+
+	target := baseLookahead[lastEpochStart]
+	validators := st.Validators()
+	validators[target].Slashed = true
+	require.NoError(t, st.SetValidators(validators))
+
+	require.NoError(t, gloas.ProcessProposerLookahead(ctx, st))
+	filtered, err := st.ProposerLookahead()
+	require.NoError(t, err)
+
+	for i := lastEpochStart; i < lookaheadSize; i++ {
+		require.NotEqual(t, target, filtered[i],
+			"slashed validator %d still selected at lookahead slot %d", target, i)
+	}
+
+	// And confirm the filter actually changed something at the target slot.
+	require.NotEqual(t, baseLookahead[lastEpochStart], filtered[lastEpochStart])
+}

beacon-chain/core/helpers/validators.go

@@ -126,6 +126,27 @@ func ActiveValidatorIndices(ctx context.Context, s state.ReadOnlyBeaconState, ep
 	return indices, nil
 }
 
+// ActiveNonSlashedValidatorIndices returns the indices of validators that are
+// both active at “epoch“ and not slashed. It is used to build the
+// EIP-8045 proposer lookahead.
+//
+// Spec pseudocode definition (EIP-8045):
+//
+//	indices = [i for i in get_active_validator_indices(state, epoch)
+//	           if not state.validators[i].slashed]
+func ActiveNonSlashedValidatorIndices(ctx context.Context, s state.ReadOnlyBeaconState, epoch primitives.Epoch) ([]primitives.ValidatorIndex, error) {
+	_, span := trace.StartSpan(ctx, "helpers.ActiveNonSlashedValidatorIndices")
+	defer span.End()
+
+	var indices []primitives.ValidatorIndex
+	for idx, val := range s.ValidatorsReadOnlySeq() {
+		if IsActiveNonSlashedValidatorUsingTrie(val, epoch) {
+			indices = append(indices, idx)
+		}
+	}
+	return indices, nil
+}
+
 // ActiveValidatorCount returns the number of active validators in the state
 // at the given epoch.
 func ActiveValidatorCount(ctx context.Context, s state.ReadOnlyBeaconState, epoch primitives.Epoch) (uint64, error) {

beacon-chain/core/requests/deposits.go

@@ -9,6 +9,7 @@ import (
 	"github.com/OffchainLabs/prysm/v7/monitoring/tracing/trace"
 	enginev1 "github.com/OffchainLabs/prysm/v7/proto/engine/v1"
 	ethpb "github.com/OffchainLabs/prysm/v7/proto/prysm/v1alpha1"
+	"github.com/OffchainLabs/prysm/v7/runtime/version"
 	"github.com/pkg/errors"
 )
 
@@ -48,16 +49,20 @@ func ProcessDepositRequests(ctx context.Context, beaconState state.BeaconState,
 //	    slot=state.slot,
 //	))
 func processDepositRequest(beaconState state.BeaconState, req *enginev1.DepositRequest) (state.BeaconState, error) {
-	requestsStartIndex, err := beaconState.DepositRequestsStartIndex()
-	if err != nil {
-		return nil, errors.Wrap(err, "could not get deposit requests start index")
-	}
 	if req == nil {
 		return nil, errors.New("nil deposit request")
 	}
-	if requestsStartIndex == params.BeaconConfig().UnsetDepositRequestsStartIndex {
-		if err := beaconState.SetDepositRequestsStartIndex(req.Index); err != nil {
-			return nil, errors.Wrap(err, "could not set deposit requests start index")
+	// [Modified in Fulu] The former deposit mechanism is removed, so the deposit
+	// requests start index is no longer set from Fulu onward.
+	if beaconState.Version() < version.Fulu {
+		requestsStartIndex, err := beaconState.DepositRequestsStartIndex()
+		if err != nil {
+			return nil, errors.Wrap(err, "could not get deposit requests start index")
+		}
+		if requestsStartIndex == params.BeaconConfig().UnsetDepositRequestsStartIndex {
+			if err := beaconState.SetDepositRequestsStartIndex(req.Index); err != nil {
+				return nil, errors.Wrap(err, "could not set deposit requests start index")
+			}
 		}
 	}
 	if err := beaconState.AppendPendingDeposit(&ethpb.PendingDeposit{

beacon-chain/core/transition/gloas.go

@@ -6,7 +6,6 @@ import (
 	"github.com/OffchainLabs/prysm/v7/beacon-chain/core/blocks"
 	"github.com/OffchainLabs/prysm/v7/beacon-chain/core/electra"
 	"github.com/OffchainLabs/prysm/v7/beacon-chain/core/epoch/precompute"
-	"github.com/OffchainLabs/prysm/v7/beacon-chain/core/fulu"
 	"github.com/OffchainLabs/prysm/v7/beacon-chain/core/gloas"
 	"github.com/OffchainLabs/prysm/v7/beacon-chain/core/helpers"
 	v "github.com/OffchainLabs/prysm/v7/beacon-chain/core/validators"
@@ -21,18 +20,9 @@ import (
 //
 // Spec definition:
 //
-//	<spec fn="process_operations" fork="gloas" hash="05a7a4ea">
+//	<spec fn="process_operations" fork="gloas" hash="e0633745">
 //	def process_operations(state: BeaconState, body: BeaconBlockBody) -> None:
-//	    # Disable former deposit mechanism once all prior deposits are processed
-//	    eth1_deposit_index_limit = min(
-//	        state.eth1_data.deposit_count, state.deposit_requests_start_index
-//	    )
-//	    if state.eth1_deposit_index < eth1_deposit_index_limit:
-//	        assert len(body.deposits) == min(
-//	            MAX_DEPOSITS, eth1_deposit_index_limit - state.eth1_deposit_index
-//	        )
-//	    else:
-//	        assert len(body.deposits) == 0
+//	    assert len(body.deposits) == 0
 //
 //	    def for_ops(operations: Sequence[Any], fn: Callable[[BeaconState, Any], None]) -> None:
 //	        for operation in operations:
@@ -43,7 +33,6 @@ import (
 //	    for_ops(body.attester_slashings, process_attester_slashing)
 //	    # [Modified in Gloas:EIP7732]
 //	    for_ops(body.attestations, process_attestation)
-//	    for_ops(body.deposits, process_deposit)
 //	    # [Modified in Gloas:EIP7732]
 //	    for_ops(body.voluntary_exits, process_voluntary_exit)
 //	    for_ops(body.bls_to_execution_changes, process_bls_to_execution_change)
@@ -200,7 +189,7 @@ func processEpochGloas(ctx context.Context, state state.BeaconState) error {
 	if err != nil {
 		return err
 	}
-	if err := fulu.ProcessProposerLookahead(ctx, state); err != nil {
+	if err := gloas.ProcessProposerLookahead(ctx, state); err != nil {
 		return err
 	}
 	return gloas.ProcessPTCWindow(ctx, state)

beacon-chain/verification/execution_payload_bid.go

@@ -132,10 +132,14 @@ func (v *BidVerifier) VerifyGasLimitTargetCompatible(parentGasLimit, targetGasLi
 // isGasLimitTargetCompatible reports whether gasLimit is compatible with
 // targetGasLimit under the EIP-1559 transition rule from parentGasLimit.
 //
-//	<spec fn="is_gas_limit_target_compatible" fork="gloas">
+//	<spec fn="is_gas_limit_target_compatible" fork="gloas" hash="3fa22023">
 //	def is_gas_limit_target_compatible(
 //	    parent_gas_limit: uint64, gas_limit: uint64, target_gas_limit: uint64
 //	) -> bool:
+//	    """
+//	    Check if ``gas_limit`` is compatible with ``target_gas_limit`` under the
+//	    EIP-1559 transition rule from ``parent_gas_limit``.
+//	    """
 //	    max_gas_limit_difference = max(parent_gas_limit // 1024, 1) - 1
 //	    min_gas_limit = parent_gas_limit - max_gas_limit_difference
 //	    max_gas_limit = parent_gas_limit + max_gas_limit_difference