-
Notifications
You must be signed in to change notification settings - Fork 926
/
beacon-chain.md
1407 lines (1176 loc) · 56.6 KB
/
beacon-chain.md
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
# Electra -- The Beacon Chain
**Notice**: This document is a work-in-progress for researchers and implementers.
## Table of contents
<!-- TOC -->
<!-- START doctoc generated TOC please keep comment here to allow auto update -->
<!-- DON'T EDIT THIS SECTION, INSTEAD RE-RUN doctoc TO UPDATE -->
- [Introduction](#introduction)
- [Constants](#constants)
- [Misc](#misc)
- [Withdrawal prefixes](#withdrawal-prefixes)
- [Domains](#domains)
- [Preset](#preset)
- [Gwei values](#gwei-values)
- [Rewards and penalties](#rewards-and-penalties)
- [State list lengths](#state-list-lengths)
- [Max operations per block](#max-operations-per-block)
- [Execution](#execution)
- [Withdrawals processing](#withdrawals-processing)
- [Configuration](#configuration)
- [Validator cycle](#validator-cycle)
- [Containers](#containers)
- [New containers](#new-containers)
- [`DepositReceipt`](#depositreceipt)
- [`PendingBalanceDeposit`](#pendingbalancedeposit)
- [`PendingPartialWithdrawal`](#pendingpartialwithdrawal)
- [`ExecutionLayerWithdrawalRequest`](#executionlayerwithdrawalrequest)
- [`Consolidation`](#consolidation)
- [`SignedConsolidation`](#signedconsolidation)
- [`PendingConsolidation`](#pendingconsolidation)
- [Modified Containers](#modified-containers)
- [`AttesterSlashing`](#attesterslashing)
- [Extended Containers](#extended-containers)
- [`Attestation`](#attestation)
- [`IndexedAttestation`](#indexedattestation)
- [`BeaconBlockBody`](#beaconblockbody)
- [`ExecutionPayload`](#executionpayload)
- [`ExecutionPayloadHeader`](#executionpayloadheader)
- [`BeaconState`](#beaconstate)
- [Helper functions](#helper-functions)
- [Predicates](#predicates)
- [Updated `is_eligible_for_activation_queue`](#updated-is_eligible_for_activation_queue)
- [New `is_compounding_withdrawal_credential`](#new-is_compounding_withdrawal_credential)
- [New `has_compounding_withdrawal_credential`](#new-has_compounding_withdrawal_credential)
- [New `has_execution_withdrawal_credential`](#new-has_execution_withdrawal_credential)
- [Updated `is_fully_withdrawable_validator`](#updated-is_fully_withdrawable_validator)
- [Updated `is_partially_withdrawable_validator`](#updated-is_partially_withdrawable_validator)
- [Misc](#misc-1)
- [`get_committee_indices`](#get_committee_indices)
- [`get_validator_max_effective_balance`](#get_validator_max_effective_balance)
- [Beacon state accessors](#beacon-state-accessors)
- [New `get_balance_churn_limit`](#new-get_balance_churn_limit)
- [New `get_activation_exit_churn_limit`](#new-get_activation_exit_churn_limit)
- [New `get_consolidation_churn_limit`](#new-get_consolidation_churn_limit)
- [New `get_active_balance`](#new-get_active_balance)
- [New `get_pending_balance_to_withdraw`](#new-get_pending_balance_to_withdraw)
- [Modified `get_attesting_indices`](#modified-get_attesting_indices)
- [Beacon state mutators](#beacon-state-mutators)
- [Updated `initiate_validator_exit`](#updated--initiate_validator_exit)
- [New `switch_to_compounding_validator`](#new-switch_to_compounding_validator)
- [New `queue_excess_active_balance`](#new-queue_excess_active_balance)
- [New `queue_entire_balance_and_reset_validator`](#new-queue_entire_balance_and_reset_validator)
- [New `compute_exit_epoch_and_update_churn`](#new-compute_exit_epoch_and_update_churn)
- [New `compute_consolidation_epoch_and_update_churn`](#new-compute_consolidation_epoch_and_update_churn)
- [Updated `slash_validator`](#updated-slash_validator)
- [Beacon chain state transition function](#beacon-chain-state-transition-function)
- [Epoch processing](#epoch-processing)
- [Updated `process_epoch`](#updated-process_epoch)
- [Updated `process_registry_updates`](#updated--process_registry_updates)
- [New `process_pending_balance_deposits`](#new-process_pending_balance_deposits)
- [New `process_pending_consolidations`](#new-process_pending_consolidations)
- [Updated `process_effective_balance_updates`](#updated-process_effective_balance_updates)
- [Block processing](#block-processing)
- [Withdrawals](#withdrawals)
- [Updated `get_expected_withdrawals`](#updated-get_expected_withdrawals)
- [Updated `process_withdrawals`](#updated-process_withdrawals)
- [Execution payload](#execution-payload)
- [Modified `process_execution_payload`](#modified-process_execution_payload)
- [Operations](#operations)
- [Modified `process_operations`](#modified-process_operations)
- [Attestations](#attestations)
- [Modified `process_attestation`](#modified-process_attestation)
- [Deposits](#deposits)
- [Updated `apply_deposit`](#updated--apply_deposit)
- [New `is_valid_deposit_signature`](#new-is_valid_deposit_signature)
- [Modified `add_validator_to_registry`](#modified-add_validator_to_registry)
- [Updated `get_validator_from_deposit`](#updated-get_validator_from_deposit)
- [Voluntary exits](#voluntary-exits)
- [Updated `process_voluntary_exit`](#updated-process_voluntary_exit)
- [Execution layer withdrawal requests](#execution-layer-withdrawal-requests)
- [New `process_execution_layer_withdrawal_request`](#new-process_execution_layer_withdrawal_request)
- [Deposit receipts](#deposit-receipts)
- [New `process_deposit_receipt`](#new-process_deposit_receipt)
- [Consolidations](#consolidations)
- [New `process_consolidation`](#new-process_consolidation)
- [Testing](#testing)
<!-- END doctoc generated TOC please keep comment here to allow auto update -->
<!-- /TOC -->
## Introduction
Electra is a consensus-layer upgrade containing a number of features. Including:
* [EIP-6110](https://eips.ethereum.org/EIPS/eip-6110): Supply validator deposits on chain
* [EIP-7002](https://eips.ethereum.org/EIPS/eip-7002): Execution layer triggerable exits
* [EIP-7251](https://eips.ethereum.org/EIPS/eip-7251): Increase the MAX_EFFECTIVE_BALANCE
* [EIP-7549](https://eips.ethereum.org/EIPS/eip-7549): Move committee index outside Attestation
*Note:* This specification is built upon [Deneb](../../deneb/beacon_chain.md) and is under active development.
## Constants
The following values are (non-configurable) constants used throughout the specification.
### Misc
| Name | Value | Description |
| - | - | - |
| `UNSET_DEPOSIT_RECEIPTS_START_INDEX` | `uint64(2**64 - 1)` | *[New in Electra:EIP6110]* |
| `FULL_EXIT_REQUEST_AMOUNT` | `uint64(0)` | *[New in Electra:EIP7002]* |
### Withdrawal prefixes
| Name | Value |
| - | - |
| `BLS_WITHDRAWAL_PREFIX` | `Bytes1('0x00')` |
| `ETH1_ADDRESS_WITHDRAWAL_PREFIX` | `Bytes1('0x01')` |
| `COMPOUNDING_WITHDRAWAL_PREFIX` | `Bytes1('0x02')` |
### Domains
| Name | Value |
| - | - |
| `DOMAIN_CONSOLIDATION` | `DomainType('0x0B000000')` |
## Preset
### Gwei values
| Name | Value |
| - | - |
| `MIN_ACTIVATION_BALANCE` | `Gwei(2**5 * 10**9)` (= 32,000,000,000) |
| `MAX_EFFECTIVE_BALANCE_ELECTRA` | `Gwei(2**11 * 10**9)` (= 2048,000,000,000) |
### Rewards and penalties
| Name | Value |
| - | - |
| `MIN_SLASHING_PENALTY_QUOTIENT_ELECTRA` | `uint64(2**12)` (= 4,096) |
| `WHISTLEBLOWER_REWARD_QUOTIENT_ELECTRA` | `uint64(2**12)` (= 4,096) |
### State list lengths
| Name | Value | Unit |
| - | - | :-: |
| `PENDING_BALANCE_DEPOSITS_LIMIT` | `uint64(2**27)` (= 134,217,728) | pending balance deposits |
| `PENDING_PARTIAL_WITHDRAWALS_LIMIT` | `uint64(2**27)` (= 134,217,728) | pending partial withdrawals |
| `PENDING_CONSOLIDATIONS_LIMIT` | `uint64(2**18)` (= 262,144) | pending consolidations |
### Max operations per block
| Name | Value |
| - | - |
| `MAX_CONSOLIDATIONS` | `uint64(1)` |
### Execution
| Name | Value | Description |
| - | - | - |
| `MAX_DEPOSIT_RECEIPTS_PER_PAYLOAD` | `uint64(2**13)` (= 8,192) | *[New in Electra:EIP6110]* Maximum number of deposit receipts allowed in each payload |
| `MAX_ATTESTER_SLASHINGS_ELECTRA` | `2**0` (= 1) | *[New in Electra:EIP7549]* |
| `MAX_ATTESTATIONS_ELECTRA` | `2**3` (= 8) | *[New in Electra:EIP7549]* |
| `MAX_WITHDRAWAL_REQUESTS_PER_PAYLOAD` | `uint64(2**4)` (= 16)| *[New in Electra:EIP7002]* Maximum number of execution layer withdrawal requests in each payload |
### Withdrawals processing
| Name | Value | Description |
| - | - | - |
| `MAX_PENDING_PARTIALS_PER_WITHDRAWALS_SWEEP` | `uint64(2**3)` (= 8)| *[New in Electra:EIP7002]* Maximum number of pending partial withdrawals to process per payload |
## Configuration
### Validator cycle
| Name | Value |
| - | - |
| `MIN_PER_EPOCH_CHURN_LIMIT_ELECTRA` | `Gwei(2**7 * 10**9)` (= 128,000,000,000) | # Equivalent to 4 32 ETH validators
| `MAX_PER_EPOCH_ACTIVATION_EXIT_CHURN_LIMIT` | `Gwei(2**8 * 10**9)` (= 256,000,000,000) |
## Containers
### New containers
#### `DepositReceipt`
*Note*: The container is new in EIP6110.
```python
class DepositReceipt(Container):
pubkey: BLSPubkey
withdrawal_credentials: Bytes32
amount: Gwei
signature: BLSSignature
index: uint64
```
#### `PendingBalanceDeposit`
*Note*: The container is new in EIP7251.
```python
class PendingBalanceDeposit(Container):
index: ValidatorIndex
amount: Gwei
```
#### `PendingPartialWithdrawal`
*Note*: The container is new in EIP7251.
```python
class PendingPartialWithdrawal(Container):
index: ValidatorIndex
amount: Gwei
withdrawable_epoch: Epoch
```
#### `ExecutionLayerWithdrawalRequest`
*Note*: The container is new in EIP7251:EIP7002.
```python
class ExecutionLayerWithdrawalRequest(Container):
source_address: ExecutionAddress
validator_pubkey: BLSPubkey
amount: Gwei
```
#### `Consolidation`
*Note*: The container is new in EIP7251.
```python
class Consolidation(Container):
source_index: ValidatorIndex
target_index: ValidatorIndex
epoch: Epoch
```
#### `SignedConsolidation`
*Note*: The container is new in EIP7251.
```python
class SignedConsolidation(Container):
message: Consolidation
signature: BLSSignature
```
#### `PendingConsolidation`
*Note*: The container is new in EIP7251.
```python
class PendingConsolidation(Container):
source_index: ValidatorIndex
target_index: ValidatorIndex
```
### Modified Containers
#### `AttesterSlashing`
```python
class AttesterSlashing(Container):
attestation_1: IndexedAttestation # [Modified in Electra:EIP7549]
attestation_2: IndexedAttestation # [Modified in Electra:EIP7549]
```
### Extended Containers
#### `Attestation`
```python
class Attestation(Container):
aggregation_bits: Bitlist[MAX_VALIDATORS_PER_COMMITTEE * MAX_COMMITTEES_PER_SLOT] # [Modified in Electra:EIP7549]
data: AttestationData
committee_bits: Bitvector[MAX_COMMITTEES_PER_SLOT] # [New in Electra:EIP7549]
signature: BLSSignature
```
#### `IndexedAttestation`
```python
class IndexedAttestation(Container):
# [Modified in Electra:EIP7549]
attesting_indices: List[ValidatorIndex, MAX_VALIDATORS_PER_COMMITTEE * MAX_COMMITTEES_PER_SLOT]
data: AttestationData
signature: BLSSignature
```
#### `BeaconBlockBody`
```python
class BeaconBlockBody(Container):
randao_reveal: BLSSignature
eth1_data: Eth1Data # Eth1 data vote
graffiti: Bytes32 # Arbitrary data
# Operations
proposer_slashings: List[ProposerSlashing, MAX_PROPOSER_SLASHINGS]
attester_slashings: List[AttesterSlashing, MAX_ATTESTER_SLASHINGS_ELECTRA] # [Modified in Electra:EIP7549]
attestations: List[Attestation, MAX_ATTESTATIONS_ELECTRA] # [Modified in Electra:EIP7549]
deposits: List[Deposit, MAX_DEPOSITS]
voluntary_exits: List[SignedVoluntaryExit, MAX_VOLUNTARY_EXITS]
sync_aggregate: SyncAggregate
# Execution
execution_payload: ExecutionPayload # [Modified in Electra:EIP6110:EIP7002]
bls_to_execution_changes: List[SignedBLSToExecutionChange, MAX_BLS_TO_EXECUTION_CHANGES]
blob_kzg_commitments: List[KZGCommitment, MAX_BLOB_COMMITMENTS_PER_BLOCK]
consolidations: List[SignedConsolidation, MAX_CONSOLIDATIONS] # [New in Electra:EIP7251]
```
#### `ExecutionPayload`
```python
class ExecutionPayload(Container):
# Execution block header fields
parent_hash: Hash32
fee_recipient: ExecutionAddress
state_root: Bytes32
receipts_root: Bytes32
logs_bloom: ByteVector[BYTES_PER_LOGS_BLOOM]
prev_randao: Bytes32
block_number: uint64
gas_limit: uint64
gas_used: uint64
timestamp: uint64
extra_data: ByteList[MAX_EXTRA_DATA_BYTES]
base_fee_per_gas: uint256
# Extra payload fields
block_hash: Hash32
transactions: List[Transaction, MAX_TRANSACTIONS_PER_PAYLOAD]
withdrawals: List[Withdrawal, MAX_WITHDRAWALS_PER_PAYLOAD]
blob_gas_used: uint64
excess_blob_gas: uint64
deposit_receipts: List[DepositReceipt, MAX_DEPOSIT_RECEIPTS_PER_PAYLOAD] # [New in Electra:EIP6110]
# [New in Electra:EIP7002:EIP7251]
withdrawal_requests: List[ExecutionLayerWithdrawalRequest, MAX_WITHDRAWAL_REQUESTS_PER_PAYLOAD]
```
#### `ExecutionPayloadHeader`
```python
class ExecutionPayloadHeader(Container):
# Execution block header fields
parent_hash: Hash32
fee_recipient: ExecutionAddress
state_root: Bytes32
receipts_root: Bytes32
logs_bloom: ByteVector[BYTES_PER_LOGS_BLOOM]
prev_randao: Bytes32
block_number: uint64
gas_limit: uint64
gas_used: uint64
timestamp: uint64
extra_data: ByteList[MAX_EXTRA_DATA_BYTES]
base_fee_per_gas: uint256
# Extra payload fields
block_hash: Hash32
transactions_root: Root
withdrawals_root: Root
blob_gas_used: uint64
excess_blob_gas: uint64
deposit_receipts_root: Root # [New in Electra:EIP6110]
withdrawal_requests_root: Root # [New in Electra:EIP7002:EIP7251]
```
#### `BeaconState`
```python
class BeaconState(Container):
# Versioning
genesis_time: uint64
genesis_validators_root: Root
slot: Slot
fork: Fork
# History
latest_block_header: BeaconBlockHeader
block_roots: Vector[Root, SLOTS_PER_HISTORICAL_ROOT]
state_roots: Vector[Root, SLOTS_PER_HISTORICAL_ROOT]
historical_roots: List[Root, HISTORICAL_ROOTS_LIMIT]
# Eth1
eth1_data: Eth1Data
eth1_data_votes: List[Eth1Data, EPOCHS_PER_ETH1_VOTING_PERIOD * SLOTS_PER_EPOCH]
eth1_deposit_index: uint64
# Registry
validators: List[Validator, VALIDATOR_REGISTRY_LIMIT]
balances: List[Gwei, VALIDATOR_REGISTRY_LIMIT]
# Randomness
randao_mixes: Vector[Bytes32, EPOCHS_PER_HISTORICAL_VECTOR]
# Slashings
slashings: Vector[Gwei, EPOCHS_PER_SLASHINGS_VECTOR] # Per-epoch sums of slashed effective balances
# Participation
previous_epoch_participation: List[ParticipationFlags, VALIDATOR_REGISTRY_LIMIT]
current_epoch_participation: List[ParticipationFlags, VALIDATOR_REGISTRY_LIMIT]
# Finality
justification_bits: Bitvector[JUSTIFICATION_BITS_LENGTH] # Bit set for every recent justified epoch
previous_justified_checkpoint: Checkpoint
current_justified_checkpoint: Checkpoint
finalized_checkpoint: Checkpoint
# Inactivity
inactivity_scores: List[uint64, VALIDATOR_REGISTRY_LIMIT]
# Sync
current_sync_committee: SyncCommittee
next_sync_committee: SyncCommittee
# Execution
latest_execution_payload_header: ExecutionPayloadHeader # [Modified in Electra:EIP6110:EIP7002]
# Withdrawals
next_withdrawal_index: WithdrawalIndex
next_withdrawal_validator_index: ValidatorIndex
# Deep history valid from Capella onwards
historical_summaries: List[HistoricalSummary, HISTORICAL_ROOTS_LIMIT]
deposit_receipts_start_index: uint64 # [New in Electra:EIP6110]
deposit_balance_to_consume: Gwei # [New in Electra:EIP7251]
exit_balance_to_consume: Gwei # [New in Electra:EIP7251]
earliest_exit_epoch: Epoch # [New in Electra:EIP7251]
consolidation_balance_to_consume: Gwei # [New in Electra:EIP7251]
earliest_consolidation_epoch: Epoch # [New in Electra:EIP7251]
pending_balance_deposits: List[PendingBalanceDeposit, PENDING_BALANCE_DEPOSITS_LIMIT] # [New in Electra:EIP7251]
# [New in Electra:EIP7251]
pending_partial_withdrawals: List[PendingPartialWithdrawal, PENDING_PARTIAL_WITHDRAWALS_LIMIT]
pending_consolidations: List[PendingConsolidation, PENDING_CONSOLIDATIONS_LIMIT] # [New in Electra:EIP7251]
```
## Helper functions
### Predicates
#### Updated `is_eligible_for_activation_queue`
```python
def is_eligible_for_activation_queue(validator: Validator) -> bool:
"""
Check if ``validator`` is eligible to be placed into the activation queue.
"""
return (
validator.activation_eligibility_epoch == FAR_FUTURE_EPOCH
and validator.effective_balance >= MIN_ACTIVATION_BALANCE # [Modified in Electra:EIP7251]
)
```
#### New `is_compounding_withdrawal_credential`
```python
def is_compounding_withdrawal_credential(withdrawal_credentials: Bytes32) -> bool:
return withdrawal_credentials[:1] == COMPOUNDING_WITHDRAWAL_PREFIX
```
#### New `has_compounding_withdrawal_credential`
```python
def has_compounding_withdrawal_credential(validator: Validator) -> bool:
"""
Check if ``validator`` has an 0x02 prefixed "compounding" withdrawal credential.
"""
return is_compounding_withdrawal_credential(validator.withdrawal_credentials)
```
#### New `has_execution_withdrawal_credential`
```python
def has_execution_withdrawal_credential(validator: Validator) -> bool:
"""
Check if ``validator`` has a 0x01 or 0x02 prefixed withdrawal credential.
"""
return has_compounding_withdrawal_credential(validator) or has_eth1_withdrawal_credential(validator)
```
#### Updated `is_fully_withdrawable_validator`
```python
def is_fully_withdrawable_validator(validator: Validator, balance: Gwei, epoch: Epoch) -> bool:
"""
Check if ``validator`` is fully withdrawable.
"""
return (
has_execution_withdrawal_credential(validator) # [Modified in Electra:EIP7251]
and validator.withdrawable_epoch <= epoch
and balance > 0
)
```
#### Updated `is_partially_withdrawable_validator`
```python
def is_partially_withdrawable_validator(validator: Validator, balance: Gwei) -> bool:
"""
Check if ``validator`` is partially withdrawable.
"""
max_effective_balance = get_validator_max_effective_balance(validator)
has_max_effective_balance = validator.effective_balance == max_effective_balance # [Modified in Electra:EIP7251]
has_excess_balance = balance > max_effective_balance # [Modified in Electra:EIP7251]
return (
has_execution_withdrawal_credential(validator) # [Modified in Electra:EIP7251]
and has_max_effective_balance
and has_excess_balance
)
```
### Misc
#### `get_committee_indices`
```python
def get_committee_indices(committee_bits: Bitvector) -> Sequence[CommitteeIndex]:
return [CommitteeIndex(index) for index, bit in enumerate(committee_bits) if bit]
```
#### `get_validator_max_effective_balance`
```python
def get_validator_max_effective_balance(validator: Validator) -> Gwei:
"""
Get max effective balance for ``validator``.
"""
if has_compounding_withdrawal_credential(validator):
return MAX_EFFECTIVE_BALANCE_ELECTRA
else:
return MIN_ACTIVATION_BALANCE
```
### Beacon state accessors
#### New `get_balance_churn_limit`
```python
def get_balance_churn_limit(state: BeaconState) -> Gwei:
"""
Return the churn limit for the current epoch.
"""
churn = max(
MIN_PER_EPOCH_CHURN_LIMIT_ELECTRA,
get_total_active_balance(state) // CHURN_LIMIT_QUOTIENT
)
return churn - churn % EFFECTIVE_BALANCE_INCREMENT
```
#### New `get_activation_exit_churn_limit`
```python
def get_activation_exit_churn_limit(state: BeaconState) -> Gwei:
"""
Return the churn limit for the current epoch dedicated to activations and exits.
"""
return min(MAX_PER_EPOCH_ACTIVATION_EXIT_CHURN_LIMIT, get_balance_churn_limit(state))
```
#### New `get_consolidation_churn_limit`
```python
def get_consolidation_churn_limit(state: BeaconState) -> Gwei:
return get_balance_churn_limit(state) - get_activation_exit_churn_limit(state)
```
#### New `get_active_balance`
```python
def get_active_balance(state: BeaconState, validator_index: ValidatorIndex) -> Gwei:
max_effective_balance = get_validator_max_effective_balance(state.validators[validator_index])
return min(state.balances[validator_index], max_effective_balance)
```
#### New `get_pending_balance_to_withdraw`
```python
def get_pending_balance_to_withdraw(state: BeaconState, validator_index: ValidatorIndex) -> Gwei:
return sum(
withdrawal.amount for withdrawal in state.pending_partial_withdrawals if withdrawal.index == validator_index
)
```
#### Modified `get_attesting_indices`
```python
def get_attesting_indices(state: BeaconState, attestation: Attestation) -> Set[ValidatorIndex]:
"""
Return the set of attesting indices corresponding to ``aggregation_bits`` and ``committee_bits``.
"""
output: Set[ValidatorIndex] = set()
committee_indices = get_committee_indices(attestation.committee_bits)
committee_offset = 0
for index in committee_indices:
committee = get_beacon_committee(state, attestation.data.slot, index)
committee_attesters = set(
index for i, index in enumerate(committee) if attestation.aggregation_bits[committee_offset + i])
output = output.union(committee_attesters)
committee_offset += len(committee)
return output
```
### Beacon state mutators
#### Updated `initiate_validator_exit`
```python
def initiate_validator_exit(state: BeaconState, index: ValidatorIndex) -> None:
"""
Initiate the exit of the validator with index ``index``.
"""
# Return if validator already initiated exit
validator = state.validators[index]
if validator.exit_epoch != FAR_FUTURE_EPOCH:
return
# Compute exit queue epoch [Modified in Electra:EIP7251]
exit_queue_epoch = compute_exit_epoch_and_update_churn(state, validator.effective_balance)
# Set validator exit epoch and withdrawable epoch
validator.exit_epoch = exit_queue_epoch
validator.withdrawable_epoch = Epoch(validator.exit_epoch + MIN_VALIDATOR_WITHDRAWABILITY_DELAY)
```
#### New `switch_to_compounding_validator`
```python
def switch_to_compounding_validator(state: BeaconState, index: ValidatorIndex) -> None:
validator = state.validators[index]
if has_eth1_withdrawal_credential(validator):
validator.withdrawal_credentials = COMPOUNDING_WITHDRAWAL_PREFIX + validator.withdrawal_credentials[1:]
queue_excess_active_balance(state, index)
```
#### New `queue_excess_active_balance`
```python
def queue_excess_active_balance(state: BeaconState, index: ValidatorIndex) -> None:
balance = state.balances[index]
if balance > MIN_ACTIVATION_BALANCE:
excess_balance = balance - MIN_ACTIVATION_BALANCE
state.balances[index] = MIN_ACTIVATION_BALANCE
state.pending_balance_deposits.append(
PendingBalanceDeposit(index=index, amount=excess_balance)
)
```
#### New `queue_entire_balance_and_reset_validator`
```python
def queue_entire_balance_and_reset_validator(state: BeaconState, index: ValidatorIndex) -> None:
balance = state.balances[index]
state.balances[index] = 0
validator = state.validators[index]
validator.effective_balance = 0
validator.activation_eligibility_epoch = FAR_FUTURE_EPOCH
state.pending_balance_deposits.append(
PendingBalanceDeposit(index=index, amount=balance)
)
```
#### New `compute_exit_epoch_and_update_churn`
```python
def compute_exit_epoch_and_update_churn(state: BeaconState, exit_balance: Gwei) -> Epoch:
earliest_exit_epoch = max(state.earliest_exit_epoch, compute_activation_exit_epoch(get_current_epoch(state)))
per_epoch_churn = get_activation_exit_churn_limit(state)
# New epoch for exits.
if state.earliest_exit_epoch < earliest_exit_epoch:
exit_balance_to_consume = per_epoch_churn
else:
exit_balance_to_consume = state.exit_balance_to_consume
# Exit doesn't fit in the current earliest epoch.
if exit_balance > exit_balance_to_consume:
balance_to_process = exit_balance - exit_balance_to_consume
additional_epochs = (balance_to_process - 1) // per_epoch_churn + 1
earliest_exit_epoch += additional_epochs
exit_balance_to_consume += additional_epochs * per_epoch_churn
# Consume the balance and update state variables.
state.exit_balance_to_consume = exit_balance_to_consume - exit_balance
state.earliest_exit_epoch = earliest_exit_epoch
return state.earliest_exit_epoch
```
#### New `compute_consolidation_epoch_and_update_churn`
```python
def compute_consolidation_epoch_and_update_churn(state: BeaconState, consolidation_balance: Gwei) -> Epoch:
earliest_consolidation_epoch = max(
state.earliest_consolidation_epoch, compute_activation_exit_epoch(get_current_epoch(state)))
per_epoch_consolidation_churn = get_consolidation_churn_limit(state)
# New epoch for consolidations.
if state.earliest_consolidation_epoch < earliest_consolidation_epoch:
consolidation_balance_to_consume = per_epoch_consolidation_churn
else:
consolidation_balance_to_consume = state.consolidation_balance_to_consume
# Consolidation doesn't fit in the current earliest epoch.
if consolidation_balance > consolidation_balance_to_consume:
balance_to_process = consolidation_balance - consolidation_balance_to_consume
additional_epochs = (balance_to_process - 1) // per_epoch_consolidation_churn + 1
earliest_consolidation_epoch += additional_epochs
consolidation_balance_to_consume += additional_epochs * per_epoch_consolidation_churn
# Consume the balance and update state variables.
state.consolidation_balance_to_consume = consolidation_balance_to_consume - consolidation_balance
state.earliest_consolidation_epoch = earliest_consolidation_epoch
return state.earliest_consolidation_epoch
```
#### Updated `slash_validator`
```python
def slash_validator(state: BeaconState,
slashed_index: ValidatorIndex,
whistleblower_index: ValidatorIndex=None) -> None:
"""
Slash the validator with index ``slashed_index``.
"""
epoch = get_current_epoch(state)
initiate_validator_exit(state, slashed_index)
validator = state.validators[slashed_index]
validator.slashed = True
validator.withdrawable_epoch = max(validator.withdrawable_epoch, Epoch(epoch + EPOCHS_PER_SLASHINGS_VECTOR))
state.slashings[epoch % EPOCHS_PER_SLASHINGS_VECTOR] += validator.effective_balance
# [Modified in Electra:EIP7251]
slashing_penalty = validator.effective_balance // MIN_SLASHING_PENALTY_QUOTIENT_ELECTRA
decrease_balance(state, slashed_index, slashing_penalty)
# Apply proposer and whistleblower rewards
proposer_index = get_beacon_proposer_index(state)
if whistleblower_index is None:
whistleblower_index = proposer_index
whistleblower_reward = Gwei(
validator.effective_balance // WHISTLEBLOWER_REWARD_QUOTIENT_ELECTRA) # [Modified in Electra:EIP7251]
proposer_reward = Gwei(whistleblower_reward * PROPOSER_WEIGHT // WEIGHT_DENOMINATOR)
increase_balance(state, proposer_index, proposer_reward)
increase_balance(state, whistleblower_index, Gwei(whistleblower_reward - proposer_reward))
```
## Beacon chain state transition function
### Epoch processing
#### Updated `process_epoch`
```python
def process_epoch(state: BeaconState) -> None:
process_justification_and_finalization(state)
process_inactivity_updates(state)
process_rewards_and_penalties(state)
process_registry_updates(state) # [Modified in Electra:EIP7251]
process_slashings(state)
process_eth1_data_reset(state)
process_pending_balance_deposits(state) # [New in Electra:EIP7251]
process_pending_consolidations(state) # [New in Electra:EIP7251]
process_effective_balance_updates(state) # [Modified in Electra:EIP7251]
process_slashings_reset(state)
process_randao_mixes_reset(state)
process_historical_summaries_update(state)
process_participation_flag_updates(state)
process_sync_committee_updates(state)
```
#### Updated `process_registry_updates`
`process_registry_updates` uses the updated definition of `initiate_validator_exit`
and changes how the activation epochs are computed for eligible validators.
```python
def process_registry_updates(state: BeaconState) -> None:
# Process activation eligibility and ejections
for index, validator in enumerate(state.validators):
if is_eligible_for_activation_queue(validator):
validator.activation_eligibility_epoch = get_current_epoch(state) + 1
if (
is_active_validator(validator, get_current_epoch(state))
and validator.effective_balance <= EJECTION_BALANCE
):
initiate_validator_exit(state, ValidatorIndex(index))
# Activate all eligible validators
activation_epoch = compute_activation_exit_epoch(get_current_epoch(state))
for validator in state.validators:
if is_eligible_for_activation(state, validator):
validator.activation_epoch = activation_epoch
```
#### New `process_pending_balance_deposits`
```python
def process_pending_balance_deposits(state: BeaconState) -> None:
available_for_processing = state.deposit_balance_to_consume + get_activation_exit_churn_limit(state)
processed_amount = 0
next_deposit_index = 0
for deposit in state.pending_balance_deposits:
if processed_amount + deposit.amount > available_for_processing:
break
increase_balance(state, deposit.index, deposit.amount)
processed_amount += deposit.amount
next_deposit_index += 1
state.pending_balance_deposits = state.pending_balance_deposits[next_deposit_index:]
if len(state.pending_balance_deposits) == 0:
state.deposit_balance_to_consume = Gwei(0)
else:
state.deposit_balance_to_consume = available_for_processing - processed_amount
```
#### New `process_pending_consolidations`
```python
def process_pending_consolidations(state: BeaconState) -> None:
next_pending_consolidation = 0
for pending_consolidation in state.pending_consolidations:
source_validator = state.validators[pending_consolidation.source_index]
if source_validator.slashed:
next_pending_consolidation += 1
continue
if source_validator.withdrawable_epoch > get_current_epoch(state):
break
# Churn any target excess active balance of target and raise its max
switch_to_compounding_validator(state, pending_consolidation.target_index)
# Move active balance to target. Excess balance is withdrawable.
active_balance = get_active_balance(state, pending_consolidation.source_index)
decrease_balance(state, pending_consolidation.source_index, active_balance)
increase_balance(state, pending_consolidation.target_index, active_balance)
next_pending_consolidation += 1
state.pending_consolidations = state.pending_consolidations[next_pending_consolidation:]
```
#### Updated `process_effective_balance_updates`
`process_effective_balance_updates` is updated with a new limit for the maximum effective balance.
```python
def process_effective_balance_updates(state: BeaconState) -> None:
# Update effective balances with hysteresis
for index, validator in enumerate(state.validators):
balance = state.balances[index]
HYSTERESIS_INCREMENT = uint64(EFFECTIVE_BALANCE_INCREMENT // HYSTERESIS_QUOTIENT)
DOWNWARD_THRESHOLD = HYSTERESIS_INCREMENT * HYSTERESIS_DOWNWARD_MULTIPLIER
UPWARD_THRESHOLD = HYSTERESIS_INCREMENT * HYSTERESIS_UPWARD_MULTIPLIER
EFFECTIVE_BALANCE_LIMIT = (
MAX_EFFECTIVE_BALANCE_ELECTRA if has_compounding_withdrawal_credential(validator)
else MIN_ACTIVATION_BALANCE
)
if (
balance + DOWNWARD_THRESHOLD < validator.effective_balance
or validator.effective_balance + UPWARD_THRESHOLD < balance
):
validator.effective_balance = min(balance - balance % EFFECTIVE_BALANCE_INCREMENT, EFFECTIVE_BALANCE_LIMIT)
```
### Block processing
```python
def process_block(state: BeaconState, block: BeaconBlock) -> None:
process_block_header(state, block)
process_withdrawals(state, block.body.execution_payload) # [Modified in Electra:EIP7251]
process_execution_payload(state, block.body, EXECUTION_ENGINE) # [Modified in Electra:EIP6110]
process_randao(state, block.body)
process_eth1_data(state, block.body)
process_operations(state, block.body) # [Modified in Electra:EIP6110:EIP7002:EIP7549:EIP7251]
process_sync_aggregate(state, block.body.sync_aggregate)
```
#### Withdrawals
##### Updated `get_expected_withdrawals`
```python
def get_expected_withdrawals(state: BeaconState) -> Tuple[Sequence[Withdrawal], uint64]:
epoch = get_current_epoch(state)
withdrawal_index = state.next_withdrawal_index
validator_index = state.next_withdrawal_validator_index
withdrawals: List[Withdrawal] = []
# [New in Electra:EIP7251] Consume pending partial withdrawals
for withdrawal in state.pending_partial_withdrawals:
if withdrawal.withdrawable_epoch > epoch or len(withdrawals) == MAX_PENDING_PARTIALS_PER_WITHDRAWALS_SWEEP:
break
validator = state.validators[withdrawal.index]
has_sufficient_effective_balance = validator.effective_balance >= MIN_ACTIVATION_BALANCE
has_excess_balance = state.balances[withdrawal.index] > MIN_ACTIVATION_BALANCE
if validator.exit_epoch == FAR_FUTURE_EPOCH and has_sufficient_effective_balance and has_excess_balance:
withdrawable_balance = min(state.balances[withdrawal.index] - MIN_ACTIVATION_BALANCE, withdrawal.amount)
withdrawals.append(Withdrawal(
index=withdrawal_index,
validator_index=withdrawal.index,
address=ExecutionAddress(validator.withdrawal_credentials[12:]),
amount=withdrawable_balance,
))
withdrawal_index += WithdrawalIndex(1)
partial_withdrawals_count = len(withdrawals)
# Sweep for remaining.
bound = min(len(state.validators), MAX_VALIDATORS_PER_WITHDRAWALS_SWEEP)
for _ in range(bound):
validator = state.validators[validator_index]
balance = state.balances[validator_index]
if is_fully_withdrawable_validator(validator, balance, epoch):
withdrawals.append(Withdrawal(
index=withdrawal_index,
validator_index=validator_index,
address=ExecutionAddress(validator.withdrawal_credentials[12:]),
amount=balance,
))
withdrawal_index += WithdrawalIndex(1)
elif is_partially_withdrawable_validator(validator, balance):
withdrawals.append(Withdrawal(
index=withdrawal_index,
validator_index=validator_index,
address=ExecutionAddress(validator.withdrawal_credentials[12:]),
amount=balance - get_validator_max_effective_balance(validator), # [Modified in Electra:EIP7251]
))
withdrawal_index += WithdrawalIndex(1)
if len(withdrawals) == MAX_WITHDRAWALS_PER_PAYLOAD:
break
validator_index = ValidatorIndex((validator_index + 1) % len(state.validators))
return withdrawals, partial_withdrawals_count
```
##### Updated `process_withdrawals`
```python
def process_withdrawals(state: BeaconState, payload: ExecutionPayload) -> None:
expected_withdrawals, partial_withdrawals_count = get_expected_withdrawals(state) # [Modified in Electra:EIP7251]
assert len(payload.withdrawals) == len(expected_withdrawals)
for expected_withdrawal, withdrawal in zip(expected_withdrawals, payload.withdrawals):
assert withdrawal == expected_withdrawal
decrease_balance(state, withdrawal.validator_index, withdrawal.amount)
# Update pending partial withdrawals [New in Electra:EIP7251]
state.pending_partial_withdrawals = state.pending_partial_withdrawals[partial_withdrawals_count:]
# Update the next withdrawal index if this block contained withdrawals
if len(expected_withdrawals) != 0:
latest_withdrawal = expected_withdrawals[-1]
state.next_withdrawal_index = WithdrawalIndex(latest_withdrawal.index + 1)
# Update the next validator index to start the next withdrawal sweep
if len(expected_withdrawals) == MAX_WITHDRAWALS_PER_PAYLOAD:
# Next sweep starts after the latest withdrawal's validator index
next_validator_index = ValidatorIndex((expected_withdrawals[-1].validator_index + 1) % len(state.validators))
state.next_withdrawal_validator_index = next_validator_index
else:
# Advance sweep by the max length of the sweep if there was not a full set of withdrawals
next_index = state.next_withdrawal_validator_index + MAX_VALIDATORS_PER_WITHDRAWALS_SWEEP
next_validator_index = ValidatorIndex(next_index % len(state.validators))
state.next_withdrawal_validator_index = next_validator_index
```
#### Execution payload
##### Modified `process_execution_payload`
*Note*: The function `process_execution_payload` is modified to use the new `ExecutionPayloadHeader` type.
```python
def process_execution_payload(state: BeaconState, body: BeaconBlockBody, execution_engine: ExecutionEngine) -> None:
payload = body.execution_payload
# Verify consistency of the parent hash with respect to the previous execution payload header
assert payload.parent_hash == state.latest_execution_payload_header.block_hash
# Verify prev_randao
assert payload.prev_randao == get_randao_mix(state, get_current_epoch(state))
# Verify timestamp
assert payload.timestamp == compute_timestamp_at_slot(state, state.slot)
# Verify commitments are under limit
assert len(body.blob_kzg_commitments) <= MAX_BLOBS_PER_BLOCK
# Verify the execution payload is valid
versioned_hashes = [kzg_commitment_to_versioned_hash(commitment) for commitment in body.blob_kzg_commitments]
assert execution_engine.verify_and_notify_new_payload(
NewPayloadRequest(
execution_payload=payload,
versioned_hashes=versioned_hashes,
parent_beacon_block_root=state.latest_block_header.parent_root,
)
)
# Cache execution payload header
state.latest_execution_payload_header = ExecutionPayloadHeader(
parent_hash=payload.parent_hash,
fee_recipient=payload.fee_recipient,
state_root=payload.state_root,
receipts_root=payload.receipts_root,