ethereum.forks.paris.state_tracker

State Tracking for Block Execution.

Track state changes on top of a read-only PreState. At block end, accumulated diffs feed into PreState.compute_state_root_and_trie_changes().

.. contents:: Table of Contents :backlinks: none :local:

Introduction

Replace the mutable State class with lightweight state trackers that record diffs. BlockState accumulates committed transaction changes across a block. TransactionState tracks in-flight changes within a single transaction and supports copy-on-write rollback.

BlockState

Accumulate committed transaction-level changes across a block.

Read chain: block writes -> pre_state.

storage_clears records addresses whose storage was wiped by a pre-EIP-6780 SELFDESTRUCT earlier in the block, so later reads must not fall back to pre_state storage.

39
@dataclass
class BlockState:

pre_state

51
    pre_state: PreState

account_writes

52
    account_writes: Dict[Address, Optional[Account]] = field(
53
        default_factory=dict
54
    )

storage_writes

55
    storage_writes: Dict[Address, Dict[Bytes32, U256]] = field(
56
        default_factory=dict
57
    )

code_writes

58
    code_writes: Dict[Hash32, Bytes] = field(default_factory=dict)

storage_clears

59
    storage_clears: Set[Address] = field(default_factory=set)

TransactionState

Track in-flight state changes within a single transaction.

Read chain: tx writes -> block writes -> pre_state.

62
@dataclass
class TransactionState:

parent

70
    parent: BlockState

account_writes

71
    account_writes: Dict[Address, Optional[Account]] = field(
72
        default_factory=dict
73
    )

storage_writes

74
    storage_writes: Dict[Address, Dict[Bytes32, U256]] = field(
75
        default_factory=dict
76
    )

code_writes

77
    code_writes: Dict[Hash32, Bytes] = field(default_factory=dict)

created_accounts

78
    created_accounts: Set[Address] = field(default_factory=set)

storage_clears

79
    storage_clears: Set[Address] = field(default_factory=set)

transient_storage

80
    transient_storage: Dict[Tuple[Address, Bytes32], U256] = field(
81
        default_factory=dict
82
    )

get_account_optional

Get the Account object at an address. Return None (rather than EMPTY_ACCOUNT) if there is no account at the address.

Parameters

tx_state : The transaction state. address : Address to look up.

Returns

account : Optional[Account] Account at address.

def get_account_optional(tx_state: TransactionState, ​​address: Address) -> Optional[Account]:
88
    """
89
    Get the ``Account`` object at an address. Return ``None`` (rather than
90
    ``EMPTY_ACCOUNT``) if there is no account at the address.
91
92
    Parameters
93
    ----------
94
    tx_state :
95
        The transaction state.
96
    address :
97
        Address to look up.
98
99
    Returns
100
    -------
101
    account : ``Optional[Account]``
102
        Account at address.
103
104
    """
105
    if address in tx_state.account_writes:
106
        return tx_state.account_writes[address]
107
    if address in tx_state.parent.account_writes:
108
        return tx_state.parent.account_writes[address]
109
    return tx_state.parent.pre_state.get_account_optional(address)

get_account

Get the Account object at an address. Return EMPTY_ACCOUNT if there is no account at the address.

Use get_account_optional() if you care about the difference between a non-existent account and EMPTY_ACCOUNT.

Parameters

tx_state : The transaction state. address : Address to look up.

Returns

account : Account Account at address.

def get_account(tx_state: TransactionState, ​​address: Address) -> Account:
113
    """
114
    Get the ``Account`` object at an address. Return ``EMPTY_ACCOUNT``
115
    if there is no account at the address.
116
117
    Use ``get_account_optional()`` if you care about the difference
118
    between a non-existent account and ``EMPTY_ACCOUNT``.
119
120
    Parameters
121
    ----------
122
    tx_state :
123
        The transaction state.
124
    address :
125
        Address to look up.
126
127
    Returns
128
    -------
129
    account : ``Account``
130
        Account at address.
131
132
    """
133
    account = get_account_optional(tx_state, address)
134
    if account is None:
135
        return EMPTY_ACCOUNT
136
    else:
137
        return account

get_code

Get the bytecode for a given code hash.

Read chain: tx code_writes -> block code_writes -> pre_state.

Parameters

tx_state : The transaction state. code_hash : Hash of the code to look up.

Returns

code : Bytes The bytecode.

def get_code(tx_state: TransactionState, ​​code_hash: Hash32) -> Bytes:
141
    """
142
    Get the bytecode for a given code hash.
143
144
    Read chain: tx code_writes -> block code_writes -> pre_state.
145
146
    Parameters
147
    ----------
148
    tx_state :
149
        The transaction state.
150
    code_hash :
151
        Hash of the code to look up.
152
153
    Returns
154
    -------
155
    code : ``Bytes``
156
        The bytecode.
157
158
    """
159
    if code_hash == EMPTY_CODE_HASH:
160
        return b""
161
    if code_hash in tx_state.code_writes:
162
        return tx_state.code_writes[code_hash]
163
    if code_hash in tx_state.parent.code_writes:
164
        return tx_state.parent.code_writes[code_hash]
165
    return tx_state.parent.pre_state.get_code(code_hash)

get_storage

Get a value at a storage key on an account. Return U256(0) if the storage key has not been set previously.

Parameters

tx_state : The transaction state. address : Address of the account. key : Key to look up.

Returns

value : U256 Value at the key.

def get_storage(tx_state: TransactionState, ​​address: Address, ​​key: Bytes32) -> U256:
171
    """
172
    Get a value at a storage key on an account. Return ``U256(0)`` if
173
    the storage key has not been set previously.
174
175
    Parameters
176
    ----------
177
    tx_state :
178
        The transaction state.
179
    address :
180
        Address of the account.
181
    key :
182
        Key to look up.
183
184
    Returns
185
    -------
186
    value : ``U256``
187
        Value at the key.
188
189
    """
190
    if address in tx_state.storage_writes:
191
        if key in tx_state.storage_writes[address]:
192
            return tx_state.storage_writes[address][key]
193
    if address in tx_state.storage_clears:
194
        return U256(0)
195
    if address in tx_state.parent.storage_writes:
196
        if key in tx_state.parent.storage_writes[address]:
197
            return tx_state.parent.storage_writes[address][key]
198
    if address in tx_state.parent.storage_clears:
199
        return U256(0)
200
    return tx_state.parent.pre_state.get_storage(address, key)

get_storage_original

Get the original value in a storage slot i.e. the value before the current transaction began. Read from block-level writes, then pre_state. Return U256(0) for accounts created in the current transaction.

Parameters

tx_state : The transaction state. address : Address of the account to read the value from. key : Key of the storage slot.

def get_storage_original(tx_state: TransactionState, ​​address: Address, ​​key: Bytes32) -> U256:
206
    """
207
    Get the original value in a storage slot i.e. the value before the
208
    current transaction began. Read from block-level writes, then
209
    pre_state. Return ``U256(0)`` for accounts created in the current
210
    transaction.
211
212
    Parameters
213
    ----------
214
    tx_state :
215
        The transaction state.
216
    address :
217
        Address of the account to read the value from.
218
    key :
219
        Key of the storage slot.
220
221
    """
222
    if address in tx_state.created_accounts:
223
        return U256(0)
224
    if address in tx_state.parent.storage_writes:
225
        if key in tx_state.parent.storage_writes[address]:
226
            return tx_state.parent.storage_writes[address][key]
227
    if address in tx_state.parent.storage_clears:
228
        return U256(0)
229
    return tx_state.parent.pre_state.get_storage(address, key)

get_transient_storage

Get a value at a storage key on an account from transient storage. Return U256(0) if the storage key has not been set previously.

Parameters

tx_state : The transaction state. address : Address of the account. key : Key to look up.

Returns

value : U256 Value at the key.

def get_transient_storage(tx_state: TransactionState, ​​address: Address, ​​key: Bytes32) -> U256:
235
    """
236
    Get a value at a storage key on an account from transient storage.
237
    Return ``U256(0)`` if the storage key has not been set previously.
238
239
    Parameters
240
    ----------
241
    tx_state :
242
        The transaction state.
243
    address :
244
        Address of the account.
245
    key :
246
        Key to look up.
247
248
    Returns
249
    -------
250
    value : ``U256``
251
        Value at the key.
252
253
    """
254
    return tx_state.transient_storage.get((address, key), U256(0))

account_exists

Check if an account exists in the state trie.

Parameters

tx_state : The transaction state. address : Address of the account that needs to be checked.

Returns

account_exists : bool True if account exists in the state trie, False otherwise.

def account_exists(tx_state: TransactionState, ​​address: Address) -> bool:
258
    """
259
    Check if an account exists in the state trie.
260
261
    Parameters
262
    ----------
263
    tx_state :
264
        The transaction state.
265
    address :
266
        Address of the account that needs to be checked.
267
268
    Returns
269
    -------
270
    account_exists : ``bool``
271
        True if account exists in the state trie, False otherwise.
272
273
    """
274
    return get_account_optional(tx_state, address) is not None

account_has_code_or_nonce

Check if an account has non-zero nonce or non-empty code.

Parameters

tx_state : The transaction state. address : Address of the account that needs to be checked.

Returns

has_code_or_nonce : bool True if the account has non-zero nonce or non-empty code, False otherwise.

def account_has_code_or_nonce(tx_state: TransactionState, ​​address: Address) -> bool:
280
    """
281
    Check if an account has non-zero nonce or non-empty code.
282
283
    Parameters
284
    ----------
285
    tx_state :
286
        The transaction state.
287
    address :
288
        Address of the account that needs to be checked.
289
290
    Returns
291
    -------
292
    has_code_or_nonce : ``bool``
293
        True if the account has non-zero nonce or non-empty code,
294
        False otherwise.
295
296
    """
297
    account = get_account(tx_state, address)
298
    return account.nonce != Uint(0) or account.code_hash != EMPTY_CODE_HASH

account_has_storage

Check if an account has storage.

Parameters

tx_state : The transaction state. address : Address of the account that needs to be checked.

Returns

has_storage : bool True if the account has storage, False otherwise.

def account_has_storage(tx_state: TransactionState, ​​address: Address) -> bool:
302
    """
303
    Check if an account has storage.
304
305
    Parameters
306
    ----------
307
    tx_state :
308
        The transaction state.
309
    address :
310
        Address of the account that needs to be checked.
311
312
    Returns
313
    -------
314
    has_storage : ``bool``
315
        True if the account has storage, False otherwise.
316
317
    """
318
    if tx_state.storage_writes.get(address):
319
        return True
320
    if address in tx_state.storage_clears:
321
        return False
322
    if tx_state.parent.storage_writes.get(address):
323
        return True
324
    if address in tx_state.parent.storage_clears:
325
        return False
326
    return tx_state.parent.pre_state.account_has_storage(address)

account_exists_and_is_empty

Check if an account exists and has zero nonce, empty code and zero balance.

Parameters

tx_state : The transaction state. address : Address of the account that needs to be checked.

Returns

exists_and_is_empty : bool True if an account exists and has zero nonce, empty code and zero balance, False otherwise.

def account_exists_and_is_empty(tx_state: TransactionState, ​​address: Address) -> bool:
332
    """
333
    Check if an account exists and has zero nonce, empty code and zero
334
    balance.
335
336
    Parameters
337
    ----------
338
    tx_state :
339
        The transaction state.
340
    address :
341
        Address of the account that needs to be checked.
342
343
    Returns
344
    -------
345
    exists_and_is_empty : ``bool``
346
        True if an account exists and has zero nonce, empty code and
347
        zero balance, False otherwise.
348
349
    """
350
    account = get_account_optional(tx_state, address)
351
    return (
352
        account is not None
353
        and account.nonce == Uint(0)
354
        and account.code_hash == EMPTY_CODE_HASH
355
        and account.balance == 0
356
    )

is_account_alive

Check whether an account is both in the state and non-empty.

Parameters

tx_state : The transaction state. address : Address of the account that needs to be checked.

Returns

is_alive : bool True if the account is alive.

def is_account_alive(tx_state: TransactionState, ​​address: Address) -> bool:
360
    """
361
    Check whether an account is both in the state and non-empty.
362
363
    Parameters
364
    ----------
365
    tx_state :
366
        The transaction state.
367
    address :
368
        Address of the account that needs to be checked.
369
370
    Returns
371
    -------
372
    is_alive : ``bool``
373
        True if the account is alive.
374
375
    """
376
    account = get_account_optional(tx_state, address)
377
    return account is not None and account != EMPTY_ACCOUNT

set_account

Set the Account object at an address. Setting to None deletes the account (but not its storage, see destroy_account()).

Parameters

tx_state : The transaction state. address : Address to set. account : Account to set at address.

def set_account(tx_state: TransactionState, ​​address: Address, ​​account: Optional[Account]) -> None:
385
    """
386
    Set the ``Account`` object at an address. Setting to ``None``
387
    deletes the account (but not its storage, see
388
    ``destroy_account()``).
389
390
    Parameters
391
    ----------
392
    tx_state :
393
        The transaction state.
394
    address :
395
        Address to set.
396
    account :
397
        Account to set at address.
398
399
    """
400
    tx_state.account_writes[address] = account

set_storage

Set a value at a storage key on an account.

Parameters

tx_state : The transaction state. address : Address of the account. key : Key to set. value : Value to set at the key.

def set_storage(tx_state: TransactionState, ​​address: Address, ​​key: Bytes32, ​​value: U256) -> None:
409
    """
410
    Set a value at a storage key on an account.
411
412
    Parameters
413
    ----------
414
    tx_state :
415
        The transaction state.
416
    address :
417
        Address of the account.
418
    key :
419
        Key to set.
420
    value :
421
        Value to set at the key.
422
423
    """
424
    assert get_account_optional(tx_state, address) is not None
425
    if address not in tx_state.storage_writes:
426
        tx_state.storage_writes[address] = {}
427
    tx_state.storage_writes[address][key] = value

destroy_account

Completely remove the account at address and all of its storage.

This function is made available exclusively for the SELFDESTRUCT opcode. It is expected that SELFDESTRUCT will be disabled in a future hardfork and this function will be removed. Only supports same transaction destruction.

Parameters

tx_state : The transaction state. address : Address of account to destroy.

def destroy_account(tx_state: TransactionState, ​​address: Address) -> None:
431
    """
432
    Completely remove the account at ``address`` and all of its storage.
433
434
    This function is made available exclusively for the ``SELFDESTRUCT``
435
    opcode. It is expected that ``SELFDESTRUCT`` will be disabled in a
436
    future hardfork and this function will be removed. Only supports same
437
    transaction destruction.
438
439
    Parameters
440
    ----------
441
    tx_state :
442
        The transaction state.
443
    address :
444
        Address of account to destroy.
445
446
    """
447
    destroy_storage(tx_state, address)
448
    set_account(tx_state, address, None)

destroy_storage

Completely remove the storage at address.

Only supports same transaction destruction.

Parameters

tx_state : The transaction state. address : Address of account whose storage is to be deleted.

def destroy_storage(tx_state: TransactionState, ​​address: Address) -> None:
452
    """
453
    Completely remove the storage at ``address``.
454
455
    Only supports same transaction destruction.
456
457
    Parameters
458
    ----------
459
    tx_state :
460
        The transaction state.
461
    address :
462
        Address of account whose storage is to be deleted.
463
464
    """
465
    if address in tx_state.storage_writes:
466
        del tx_state.storage_writes[address]
467
    tx_state.storage_clears.add(address)

mark_account_created

Mark an account as having been created in the current transaction. This information is used by get_storage_original() to handle an obscure edgecase, and to respect the constraints added to SELFDESTRUCT by EIP-6780.

The marker is not removed even if the account creation reverts. Since the account cannot have had code prior to its creation and can't call get_storage_original(), this is harmless.

Parameters

tx_state : The transaction state. address : Address of the account that has been created.

def mark_account_created(tx_state: TransactionState, ​​address: Address) -> None:
471
    """
472
    Mark an account as having been created in the current transaction.
473
    This information is used by ``get_storage_original()`` to handle an
474
    obscure edgecase, and to respect the constraints added to
475
    SELFDESTRUCT by EIP-6780.
476
477
    The marker is not removed even if the account creation reverts.
478
    Since the account cannot have had code prior to its creation and
479
    can't call ``get_storage_original()``, this is harmless.
480
481
    Parameters
482
    ----------
483
    tx_state :
484
        The transaction state.
485
    address :
486
        Address of the account that has been created.
487
488
    """
489
    tx_state.created_accounts.add(address)

set_transient_storage

Set a value at a storage key on an account in transient storage.

Parameters

tx_state : The transaction state. address : Address of the account. key : Key to set. value : Value to set at the key.

def set_transient_storage(tx_state: TransactionState, ​​address: Address, ​​key: Bytes32, ​​value: U256) -> None:
498
    """
499
    Set a value at a storage key on an account in transient storage.
500
501
    Parameters
502
    ----------
503
    tx_state :
504
        The transaction state.
505
    address :
506
        Address of the account.
507
    key :
508
        Key to set.
509
    value :
510
        Value to set at the key.
511
512
    """
513
    if value == U256(0):
514
        tx_state.transient_storage.pop((address, key), None)
515
    else:
516
        tx_state.transient_storage[(address, key)] = value

modify_state

Modify an Account in the state. If, after modification, the account exists and has zero nonce, empty code, and zero balance, it is destroyed.

def modify_state(tx_state: TransactionState, ​​address: Address, ​​f: Callable[[Account], None]) -> None:
524
    """
525
    Modify an ``Account`` in the state. If, after modification, the
526
    account exists and has zero nonce, empty code, and zero balance, it
527
    is destroyed.
528
    """
529
    set_account(tx_state, address, modify(get_account(tx_state, address), f))
530
    if account_exists_and_is_empty(tx_state, address):
531
        destroy_account(tx_state, address)

move_ether

Move funds between accounts.

Parameters

tx_state : The transaction state. sender_address : Address of the sender. recipient_address : Address of the recipient. amount : The amount to transfer.

def move_ether(tx_state: TransactionState, ​​sender_address: Address, ​​recipient_address: Address, ​​amount: U256) -> None:
540
    """
541
    Move funds between accounts.
542
543
    Parameters
544
    ----------
545
    tx_state :
546
        The transaction state.
547
    sender_address :
548
        Address of the sender.
549
    recipient_address :
550
        Address of the recipient.
551
    amount :
552
        The amount to transfer.
553
554
    """
555
556
    def reduce_sender_balance(sender: Account) -> None:
557
        if sender.balance < amount:
558
            raise AssertionError
559
        sender.balance -= amount
560
561
    def increase_recipient_balance(recipient: Account) -> None:
562
        recipient.balance += amount
563
564
    modify_state(tx_state, sender_address, reduce_sender_balance)
565
    modify_state(tx_state, recipient_address, increase_recipient_balance)

create_ether

Add newly created ether to an account.

Parameters

tx_state : The transaction state. address : Address of the account to which ether is added. amount : The amount of ether to be added to the account of interest.

def create_ether(tx_state: TransactionState, ​​address: Address, ​​amount: U256) -> None:
571
    """
572
    Add newly created ether to an account.
573
574
    Parameters
575
    ----------
576
    tx_state :
577
        The transaction state.
578
    address :
579
        Address of the account to which ether is added.
580
    amount :
581
        The amount of ether to be added to the account of interest.
582
583
    """
584
585
    def increase_balance(account: Account) -> None:
586
        account.balance += amount
587
588
    modify_state(tx_state, address, increase_balance)

set_account_balance

Set the balance of an account.

Parameters

tx_state : The transaction state. address : Address of the account whose balance needs to be set. amount : The amount that needs to be set in the balance.

def set_account_balance(tx_state: TransactionState, ​​address: Address, ​​amount: U256) -> None:
594
    """
595
    Set the balance of an account.
596
597
    Parameters
598
    ----------
599
    tx_state :
600
        The transaction state.
601
    address :
602
        Address of the account whose balance needs to be set.
603
    amount :
604
        The amount that needs to be set in the balance.
605
606
    """
607
608
    def set_balance(account: Account) -> None:
609
        account.balance = amount
610
611
    modify_state(tx_state, address, set_balance)

increment_nonce

Increment the nonce of an account.

Parameters

tx_state : The transaction state. address : Address of the account whose nonce needs to be incremented.

def increment_nonce(tx_state: TransactionState, ​​address: Address) -> None:
615
    """
616
    Increment the nonce of an account.
617
618
    Parameters
619
    ----------
620
    tx_state :
621
        The transaction state.
622
    address :
623
        Address of the account whose nonce needs to be incremented.
624
625
    """
626
627
    def increase_nonce(sender: Account) -> None:
628
        sender.nonce += Uint(1)
629
630
    modify_state(tx_state, address, increase_nonce)

set_code

Set Account code.

Parameters

tx_state : The transaction state. address : Address of the account whose code needs to be updated. code : The bytecode that needs to be set.

def set_code(tx_state: TransactionState, ​​address: Address, ​​code: Bytes) -> None:
636
    """
637
    Set Account code.
638
639
    Parameters
640
    ----------
641
    tx_state :
642
        The transaction state.
643
    address :
644
        Address of the account whose code needs to be updated.
645
    code :
646
        The bytecode that needs to be set.
647
648
    """
649
    code_hash = keccak256(code)
650
    if code_hash != EMPTY_CODE_HASH:
651
        tx_state.code_writes[code_hash] = code
652
653
    def write_code_hash(sender: Account) -> None:
654
        sender.code_hash = code_hash
655
656
    modify_state(tx_state, address, write_code_hash)

copy_tx_state

Create a snapshot of the transaction state for rollback.

Deep-copy writes and transient storage. The parent reference and created_accounts are shared (not rolled back).

Parameters

tx_state : The transaction state to snapshot.

Returns

snapshot : TransactionState A copy of the transaction state.

def copy_tx_state(tx_state: TransactionState) -> TransactionState:
663
    """
664
    Create a snapshot of the transaction state for rollback.
665
666
    Deep-copy writes and transient storage.  The parent reference and
667
    ``created_accounts`` are shared (not rolled back).
668
669
    Parameters
670
    ----------
671
    tx_state :
672
        The transaction state to snapshot.
673
674
    Returns
675
    -------
676
    snapshot : ``TransactionState``
677
        A copy of the transaction state.
678
679
    """
680
    return TransactionState(
681
        parent=tx_state.parent,
682
        account_writes=dict(tx_state.account_writes),
683
        storage_writes={
684
            addr: dict(slots)
685
            for addr, slots in tx_state.storage_writes.items()
686
        },
687
        code_writes=dict(tx_state.code_writes),
688
        created_accounts=tx_state.created_accounts,
689
        storage_clears=set(tx_state.storage_clears),
690
        transient_storage=dict(tx_state.transient_storage),
691
    )

restore_tx_state

Restore transaction state from a snapshot (rollback on failure).

Parameters

tx_state : The transaction state to restore. snapshot : The snapshot to restore from.

def restore_tx_state(tx_state: TransactionState, ​​snapshot: TransactionState) -> None:
697
    """
698
    Restore transaction state from a snapshot (rollback on failure).
699
700
    Parameters
701
    ----------
702
    tx_state :
703
        The transaction state to restore.
704
    snapshot :
705
        The snapshot to restore from.
706
707
    """
708
    tx_state.account_writes = snapshot.account_writes
709
    tx_state.storage_writes = snapshot.storage_writes
710
    tx_state.code_writes = snapshot.code_writes
711
    tx_state.storage_clears = snapshot.storage_clears
712
    tx_state.transient_storage = snapshot.transient_storage

incorporate_tx_into_block

Merge transaction writes into the block state and clear for reuse.

Parameters

tx_state : The transaction state to commit.

def incorporate_tx_into_block(tx_state: TransactionState) -> None:
719
    """
720
    Merge transaction writes into the block state and clear for reuse.
721
722
    Parameters
723
    ----------
724
    tx_state :
725
        The transaction state to commit.
726
727
    """
728
    block = tx_state.parent
729
730
    for address, account in tx_state.account_writes.items():
731
        block.account_writes[address] = account
732
733
    for address in tx_state.storage_clears:
734
        block.storage_clears.add(address)
735
        block.storage_writes.pop(address, None)
736
737
    for address, slots in tx_state.storage_writes.items():
738
        if address not in block.storage_writes:
739
            block.storage_writes[address] = {}
740
        block.storage_writes[address].update(slots)
741
742
    block.code_writes.update(tx_state.code_writes)
743
744
    tx_state.account_writes.clear()
745
    tx_state.storage_writes.clear()
746
    tx_state.code_writes.clear()
747
    tx_state.created_accounts.clear()
748
    tx_state.storage_clears.clear()
749
    tx_state.transient_storage.clear()

extract_block_diff

Extract account, storage, and code diff from the block state.

Parameters

block_state : The block state.

Returns

diff : BlockDiff Account, storage, and code changes accumulated during block execution.

def extract_block_diff(block_state: BlockState) -> BlockDiff:
753
    """
754
    Extract account, storage, and code diff from the block state.
755
756
    Parameters
757
    ----------
758
    block_state :
759
        The block state.
760
761
    Returns
762
    -------
763
    diff : `BlockDiff`
764
        Account, storage, and code changes accumulated during block execution.
765
766
    """
767
    return BlockDiff(
768
        account_changes=block_state.account_writes,
769
        storage_changes=block_state.storage_writes,
770
        code_changes=block_state.code_writes,
771
        storage_clears=block_state.storage_clears,
772
    )