fix validator_indicies issue in process_attester_slashing

specs/core/0_beacon-chain.md

@@ -2291,10 +2291,12 @@ def process_attester_slashing(state: BeaconState,
 
     assert verify_indexed_attestation(state, attestation1)
     assert verify_indexed_attestation(state, attestation2)
+    validator_indices_1 = attestation1.custody_bit_0_indices + attestation1.custody_bit_1_indices
+    validator_indices_2 = attestation2.custody_bit_0_indices + attestation2.custody_bit_1_indices
     slashable_indices = [
-        index for index in attestation1.validator_indices
+        index for index in validator_indices_1
         if (
-            index in attestation2.validator_indices and
+            index in validator_indices_2 and
             is_slashable_validator(state.validator_registry[index], get_current_epoch(state))
         )
     ]

tests/phase0/helpers.py

@@ -12,6 +12,7 @@ from build.phase0.spec import (
     Attestation,
     AttestationData,
     AttestationDataAndCustodyBit,
+    AttesterSlashing,
     BeaconBlockHeader,
     Deposit,
     DepositData,
@@ -19,6 +20,7 @@ from build.phase0.spec import (
     ProposerSlashing,
     VoluntaryExit,
     # functions
+    convert_to_indexed,
     get_active_validator_indices,
     get_attestation_participants,
     get_block_root,
@@ -244,6 +246,17 @@ def get_valid_proposer_slashing(state):
     )
 
 
+def get_valid_attester_slashing(state):
+    attestation_1 = get_valid_attestation(state)
+    attestation_2 = deepcopy(attestation_1)
+    attestation_2.data.target_root = b'\x01'*32
+
+    return AttesterSlashing(
+        attestation_1=convert_to_indexed(state, attestation_1),
+        attestation_2=convert_to_indexed(state, attestation_2),
+    )
+
+
 def get_valid_attestation(state, slot=None):
     if slot is None:
         slot = state.slot

tests/phase0/test_sanity.py

@@ -40,6 +40,7 @@ from tests.phase0.helpers import (
     build_empty_block_for_next_slot,
     force_registry_change_at_next_epoch,
     get_valid_attestation,
+    get_valid_attester_slashing,
     get_valid_proposer_slashing,
     privkeys,
     pubkeys,
@@ -140,6 +141,33 @@ def test_proposer_slashing(state):
     return state, [block], test_state
 
 
+def test_attester_slashing(state):
+    test_state = deepcopy(state)
+    attester_slashing = get_valid_attester_slashing(state)
+    validator_index = attester_slashing.attestation_1.custody_bit_0_indices[0]
+
+    #
+    # Add to state via block transition
+    #
+    block = build_empty_block_for_next_slot(test_state)
+    block.body.attester_slashings.append(attester_slashing)
+    state_transition(test_state, block)
+
+    assert not state.validator_registry[validator_index].initiated_exit
+    assert not state.validator_registry[validator_index].slashed
+
+    slashed_validator = test_state.validator_registry[validator_index]
+    assert not slashed_validator.initiated_exit
+    assert slashed_validator.slashed
+    assert slashed_validator.exit_epoch < spec.FAR_FUTURE_EPOCH
+    assert slashed_validator.withdrawable_epoch < spec.FAR_FUTURE_EPOCH
+    # lost whistleblower reward
+    assert get_balance(test_state, validator_index) < get_balance(state, validator_index)
+
+    return state, [block], test_state
+
+
+
 def test_deposit_in_block(state):
     pre_state = deepcopy(state)
     test_deposit_data_leaves = [ZERO_HASH] * len(pre_state.validator_registry)