Exclude slashed validators from proposing (EIP-8045)

specs/gloas/beacon-chain.md

@@ -56,6 +56,7 @@
     - [Modified `compute_proposer_indices`](#modified-compute_proposer_indices)
     - [New `compute_ptc`](#new-compute_ptc)
   - [Beacon state accessors](#beacon-state-accessors)
+    - [Modified `get_beacon_proposer_indices`](#modified-get_beacon_proposer_indices)
     - [Modified `get_next_sync_committee_indices`](#modified-get_next_sync_committee_indices)
     - [Modified `get_attestation_participation_flag_indices`](#modified-get_attestation_participation_flag_indices)
     - [New `get_ptc`](#new-get_ptc)
@@ -118,6 +119,8 @@ Gloas is a consensus-layer upgrade containing a number of features. Including:
 - [EIP-7732](https://eips.ethereum.org/EIPS/eip-7732): Enshrined
   Proposer-Builder Separation
 - [EIP-7843](https://eips.ethereum.org/EIPS/eip-7843): SLOTNUM opcode
+- [EIP-8045](https://eips.ethereum.org/EIPS/eip-8045): Exclude slashed
+  validators from proposing
 - [EIP-8061](https://eips.ethereum.org/EIPS/eip-8061): Increase exit and
   consolidation churn
 
@@ -682,6 +685,29 @@ def compute_ptc(state: BeaconState, slot: Slot) -> Vector[ValidatorIndex, PTC_SI
 
 ### Beacon state accessors
 
+#### Modified `get_beacon_proposer_indices`
+
+*Note*: `get_beacon_proposer_indices` is modified to exclude slashed validators
+from the candidate pool before invoking `compute_proposer_indices`, so the newly
+computed proposer indices only contain active and unslashed validators.
+
+```python
+def get_beacon_proposer_indices(
+    state: BeaconState, epoch: Epoch
+) -> Vector[ValidatorIndex, SLOTS_PER_EPOCH]:
+    """
+    Return the proposer indices for the given ``epoch``.
+    """
+    # [Modified in Gloas:EIP8045]
+    indices = [
+        index
+        for index in get_active_validator_indices(state, epoch)
+        if not state.validators[index].slashed
+    ]
+    seed = get_seed(state, epoch, DOMAIN_BEACON_PROPOSER)
+    return compute_proposer_indices(state, epoch, seed, indices)
+```
+
 #### Modified `get_next_sync_committee_indices`
 
 *Note*: `get_next_sync_committee_indices` is modified to use

tests/core/pyspec/eth_consensus_specs/test/gloas/epoch_processing/test_process_proposer_lookahead.py

@@ -0,0 +1,51 @@
+from eth_consensus_specs.test.context import spec_state_test, with_gloas_and_later
+from eth_consensus_specs.test.helpers.epoch_processing import run_epoch_processing_with
+from eth_consensus_specs.test.helpers.state import next_epoch
+
+
+@with_gloas_and_later
+@spec_state_test
+def test_proposer_lookahead_does_not_contain_slashed_validators(spec, state):
+    """
+    [EIP-8045] The newly appended epoch of ``proposer_lookahead`` must not
+    reference slashed validators.
+    """
+    for _ in range(spec.MIN_SEED_LOOKAHEAD + 1):
+        next_epoch(spec, state)
+
+    active = spec.get_active_validator_indices(state, spec.get_current_epoch(state))
+    to_slash = set(active[: len(active) // 2])
+    for validator_index in to_slash:
+        state.validators[validator_index].slashed = True
+
+    yield from run_epoch_processing_with(spec, state, "process_proposer_lookahead")
+
+    last_epoch_start = len(state.proposer_lookahead) - spec.SLOTS_PER_EPOCH
+    for validator_index in state.proposer_lookahead[last_epoch_start:]:
+        assert validator_index not in to_slash
+        assert not state.validators[validator_index].slashed
+
+
+@with_gloas_and_later
+@spec_state_test
+def test_proposer_lookahead_full_with_many_slashed_validators(spec, state):
+    """
+    [EIP-8045] The lookahead must still fill its full ``SLOTS_PER_EPOCH`` entries
+    when only a small subset of active validators remain unslashed.
+    """
+    for _ in range(spec.MIN_SEED_LOOKAHEAD + 1):
+        next_epoch(spec, state)
+
+    active = spec.get_active_validator_indices(state, spec.get_current_epoch(state))
+    keep = max(spec.SLOTS_PER_EPOCH, 8)
+    assert len(active) > keep
+    for validator_index in active[keep:]:
+        state.validators[validator_index].slashed = True
+
+    yield from run_epoch_processing_with(spec, state, "process_proposer_lookahead")
+
+    last_epoch_start = len(state.proposer_lookahead) - spec.SLOTS_PER_EPOCH
+    last_epoch_proposers = list(state.proposer_lookahead[last_epoch_start:])
+    assert len(last_epoch_proposers) == spec.SLOTS_PER_EPOCH
+    for validator_index in last_epoch_proposers:
+        assert not state.validators[validator_index].slashed

tests/core/pyspec/eth_consensus_specs/test/gloas/fork/test_gloas_fork_proposer_lookahead.py

@@ -0,0 +1,53 @@
+from eth_consensus_specs.test.context import (
+    spec_test,
+    with_phases,
+    with_state,
+)
+from eth_consensus_specs.test.helpers.constants import (
+    FULU,
+    GLOAS,
+)
+from eth_consensus_specs.test.helpers.fork_transition import do_fork_generate
+from eth_consensus_specs.test.helpers.gloas.fork import GLOAS_FORK_TEST_META_TAGS
+from eth_consensus_specs.test.helpers.state import (
+    next_epoch,
+    transition_to,
+)
+from eth_consensus_specs.test.utils import with_meta_tags
+
+
+def _transition_to_last_slot_before_fork(spec, state):
+    """
+    Advance a couple of epochs so the proposer lookahead is fully populated by
+    regular epoch processing, then stop at the last slot of the epoch right
+    before the fork (where ``do_fork_generate`` expects to take over).
+    """
+    for _ in range(2):
+        next_epoch(spec, state)
+    fork_epoch = spec.get_current_epoch(state) + 1
+    transition_to(spec, state, fork_epoch * spec.SLOTS_PER_EPOCH - 1)
+    return fork_epoch
+
+
+@with_phases(phases=[FULU], other_phases=[GLOAS])
+@spec_test
+@with_state
+@with_meta_tags(GLOAS_FORK_TEST_META_TAGS)
+def test_fork_proposer_lookahead_slashed_validators_carried_over(spec, phases, state):
+    """
+    Test that both proposer lookahead epochs can contain slashed validators
+    after the fork.
+    """
+    gloas = phases[GLOAS]
+    fork_epoch = _transition_to_last_slot_before_fork(spec, state)
+
+    # Slash half of the validator set
+    for validator_index in range(len(state.validators) // 2):
+        state.validators[validator_index].slashed = True
+
+    state, _ = yield from do_fork_generate(state, spec, gloas, fork_epoch, with_block=False)
+
+    # Both halves were computed under Fulu, so both still have slashed validators
+    half = spec.SLOTS_PER_EPOCH
+    assert any(state.validators[v].slashed for v in state.proposer_lookahead[:half])
+    assert any(state.validators[v].slashed for v in state.proposer_lookahead[half:])

tests/core/pyspec/eth_consensus_specs/test/gloas/sanity/test_blocks.py

@@ -1,4 +1,10 @@
-from eth_consensus_specs.test.context import always_bls, spec_state_test, with_gloas_and_later
+from eth_consensus_specs.test.context import (
+    always_bls,
+    GLOAS,
+    spec_state_test,
+    with_gloas_and_later,
+    with_phases,
+)
 from eth_consensus_specs.test.gloas.block_processing.test_process_payload_attestation import (
     prepare_signed_payload_attestation,
 )
@@ -11,6 +17,7 @@
 )
 from eth_consensus_specs.test.helpers.keys import builder_privkeys, privkeys
 from eth_consensus_specs.test.helpers.state import (
+    next_epoch,
     next_epoch_with_full_participation,
     state_transition_and_sign_block,
 )
@@ -590,3 +597,46 @@ def test_voluntary_exit_fails_after_parent_payload_withdrawal_request(spec, stat
     signed_block = state_transition_and_sign_block(spec, state, block, expect_fail=True)
     yield "blocks", [signed_block]
     yield "post", None
+
+
+@with_phases([GLOAS])
+@spec_state_test
+def test_proposer_lookahead_excludes_slashed_validators(spec, state):
+    """
+    Test that slashed validators are excluded from the proposer lookahead.
+    """
+    for _ in range(2):
+        next_epoch(spec, state)
+
+    current_epoch = spec.get_current_epoch(state)
+    new_half_epoch = current_epoch + spec.MIN_SEED_LOOKAHEAD + 1
+
+    # Slash some validators
+    for validator_index in range(len(state.validators) // 2):
+        state.validators[validator_index].slashed = True
+
+    # Fulu includes slashed validators
+    proposers_in_fulu = spec.fulu.get_beacon_proposer_indices(state, new_half_epoch)
+    assert any(state.validators[v].slashed for v in proposers_in_fulu)
+
+    # Gloas excludes slashed validators
+    proposers_in_gloas = spec.get_beacon_proposer_indices(state, new_half_epoch)
+    assert not any(state.validators[v].slashed for v in proposers_in_gloas)
+
+    # Cross into the next epoch with a block, picking a slot whose proposer is
+    # not one of the validators we slashed so the block is valid
+    epoch_n1_proposers = list(state.proposer_lookahead[spec.SLOTS_PER_EPOCH :])
+    offset = next(i for i, p in enumerate(epoch_n1_proposers) if not state.validators[p].slashed)
+    block_slot = (current_epoch + 1) * spec.SLOTS_PER_EPOCH + offset
+
+    yield "pre", state
+
+    block = build_empty_block(spec, state, slot=block_slot)
+    signed_block = state_transition_and_sign_block(spec, state, block)
+
+    yield "blocks", [signed_block]
+    yield "post", state
+
+    # The newly appended lookahead epoch matches the Gloas selection
+    last_epoch_start = len(state.proposer_lookahead) - spec.SLOTS_PER_EPOCH
+    assert list(state.proposer_lookahead[last_epoch_start:]) == list(proposers_in_gloas)