ethereum.forks.gray_glacier.forkethereum.forks.paris.fork

Ethereum Specification.

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

Introduction

Entry point for the Ethereum specification.

BLOCK_REWARD

71
BLOCK_REWARD = U256(2 * 10**18)

BASE_FEE_MAX_CHANGE_DENOMINATOR

68
BASE_FEE_MAX_CHANGE_DENOMINATOR = Uint(8)

ELASTICITY_MULTIPLIER

69
ELASTICITY_MULTIPLIER = Uint(2)

MINIMUM_DIFFICULTY

74
MINIMUM_DIFFICULTY = Uint(131072)

MAX_OMMER_DEPTH

75
MAX_OMMER_DEPTH = Uint(6)

BOMB_DELAY_BLOCKS

76
BOMB_DELAY_BLOCKS = 11400000

EMPTY_OMMER_HASH

70
EMPTY_OMMER_HASH = keccak256(rlp.encode([]))

BlockChain

History and current state of the block chain.

73
@final
74
@dataclass
class BlockChain:

blocks

80
    blocks: List[Block]

state

81
    state: State

chain_id

82
    chain_id: U64

apply_fork

Transforms the state from the previous hard fork (old) into the block chain object for this hard fork and returns it.

When forks need to implement an irregular state transition, this function is used to handle the irregularity. See the :ref:DAO Fork <dao-fork> for an example.

Parameters

old : Previous block chain object.

Returns

new : BlockChain Upgraded block chain object for this hard fork.

def apply_fork(old: BlockChain) -> BlockChain:
86
    <snip>
105
    return old

get_last_256_block_hashes

Obtain the list of hashes of the previous 256 blocks in order of increasing block number.

This function will return less hashes for the first 256 blocks.

The BLOCKHASH opcode needs to access the latest hashes on the chain, therefore this function retrieves them.

Parameters

chain : History and current state.

Returns

recent_block_hashes : List[Hash32] Hashes of the recent 256 blocks in order of increasing block number.

def get_last_256_block_hashes(chain: BlockChain) -> List[Hash32]:
109
    <snip>
129
    recent_blocks = chain.blocks[-255:]
130
    # TODO: This function has not been tested rigorously
131
    if len(recent_blocks) == 0:
132
        return []
133
134
    recent_block_hashes = []
135
136
    for block in recent_blocks:
137
        prev_block_hash = block.header.parent_hash
138
        recent_block_hashes.append(prev_block_hash)
139
140
    # We are computing the hash only for the most recent block and not for
141
    # the rest of the blocks as they have successors which have the hash of
142
    # the current block as parent hash.
143
    most_recent_block_hash = keccak256(rlp.encode(recent_blocks[-1].header))
144
    recent_block_hashes.append(most_recent_block_hash)
145
146
    return recent_block_hashes

state_transition

Attempts to apply a block to an existing block chain.

All parts of the block's contents need to be verified before being added to the chain. Blocks are verified by ensuring that the contents of the block make logical sense with the contents of the parent block. The information in the block's header must also match the corresponding information in the block.

To implement Ethereum, in theory clients are only required to store the most recent 255 blocks of the chain since as far as execution is concerned, only those blocks are accessed. Practically, however, clients should store more blocks to handle reorgs.

Parameters

chain : History and current state. block : Block to apply to chain.

def state_transition(chain: BlockChain, ​​block: Block) -> None:
150
    <snip>
172
    validate_header(chain, block.header)
180
    validate_ommers(block.ommers, block.header, chain)
173
    if block.ommers != ():
174
        raise InvalidBlock
175
176
    block_state = BlockState(pre_state=chain.state)
177
178
    block_env = vm.BlockEnvironment(
179
        chain_id=chain.chain_id,
180
        state=block_state,
181
        block_gas_limit=block.header.gas_limit,
182
        block_hashes=get_last_256_block_hashes(chain),
183
        coinbase=block.header.coinbase,
184
        number=block.header.number,
185
        base_fee_per_gas=block.header.base_fee_per_gas,
186
        time=block.header.timestamp,
193
        difficulty=block.header.difficulty,
187
        prev_randao=block.header.prev_randao,
188
    )
189
190
    block_output = apply_body(
191
        block_env=block_env,
192
        transactions=block.transactions,
199
        ommers=block.ommers,
193
    )
194
    block_diff = extract_block_diff(block_state)
195
    block_state_root = chain.state.compute_state_root(block_diff)
196
    transactions_root = root(block_output.transactions_trie)
197
    receipt_root = root(block_output.receipts_trie)
198
    block_logs_bloom = logs_bloom(block_output.block_logs)
199
200
    if block_output.block_gas_used != block.header.gas_used:
201
        raise InvalidBlock(
202
            f"{block_output.block_gas_used} != {block.header.gas_used}"
203
        )
204
    if transactions_root != block.header.transactions_root:
205
        raise InvalidBlock
206
    if block_state_root != block.header.state_root:
207
        raise InvalidBlock
208
    if receipt_root != block.header.receipt_root:
209
        raise InvalidBlock
210
    if block_logs_bloom != block.header.bloom:
211
        raise InvalidBlock
212
213
    apply_changes_to_state(chain.state, block_diff)
214
    chain.blocks.append(block)
215
    if len(chain.blocks) > 255:
216
        # Real clients have to store more blocks to deal with reorgs, but the
217
        # protocol only requires the last 255
218
        chain.blocks = chain.blocks[-255:]

calculate_base_fee_per_gas

Calculates the base fee per gas for the block.

Parameters

block_gas_limit : Gas limit of the block for which the base fee is being calculated. parent_gas_limit : Gas limit of the parent block. parent_gas_used : Gas used in the parent block. parent_base_fee_per_gas : Base fee per gas of the parent block.

Returns

base_fee_per_gas : Uint Base fee per gas for the block.

def calculate_base_fee_per_gas(block_gas_limit: Uint, ​​parent_gas_limit: Uint, ​​parent_gas_used: Uint, ​​parent_base_fee_per_gas: Uint) -> Uint:
227
    <snip>
247
    parent_gas_target = parent_gas_limit // ELASTICITY_MULTIPLIER
248
    if not check_gas_limit(block_gas_limit, parent_gas_limit):
249
        raise InvalidBlock
250
251
    if parent_gas_used == parent_gas_target:
252
        expected_base_fee_per_gas = parent_base_fee_per_gas
253
    elif parent_gas_used > parent_gas_target:
254
        gas_used_delta = parent_gas_used - parent_gas_target
255
256
        parent_fee_gas_delta = parent_base_fee_per_gas * gas_used_delta
257
        target_fee_gas_delta = parent_fee_gas_delta // parent_gas_target
258
259
        base_fee_per_gas_delta = max(
260
            target_fee_gas_delta // BASE_FEE_MAX_CHANGE_DENOMINATOR,
261
            Uint(1),
262
        )
263
264
        expected_base_fee_per_gas = (
265
            parent_base_fee_per_gas + base_fee_per_gas_delta
266
        )
267
    else:
268
        gas_used_delta = parent_gas_target - parent_gas_used
269
270
        parent_fee_gas_delta = parent_base_fee_per_gas * gas_used_delta
271
        target_fee_gas_delta = parent_fee_gas_delta // parent_gas_target
272
273
        base_fee_per_gas_delta = (
274
            target_fee_gas_delta // BASE_FEE_MAX_CHANGE_DENOMINATOR
275
        )
276
277
        expected_base_fee_per_gas = (
278
            parent_base_fee_per_gas - base_fee_per_gas_delta
279
        )
280
281
    return Uint(expected_base_fee_per_gas)

validate_header

Verifies a block header.

In order to consider a block's header valid, the logic for the quantities in the header should match the logic for the block itself. For example the header timestamp should be greater than the block's parent timestamp because the block was created after the parent block. Additionally, the block's number should be directly following the parent block's number since it is the next block in the sequence.

Parameters

chain : History and current state. header : Header to check for correctness.

def validate_header(chain: BlockChain, ​​header: Header) -> None:
285
    <snip>
303
    if header.number < Uint(1):
304
        raise InvalidBlock
312
    parent_header_number = header.number - Uint(1)
313
    first_block_number = chain.blocks[0].header.number
314
    last_block_number = chain.blocks[-1].header.number
305
316
    if (
317
        parent_header_number < first_block_number
318
        or parent_header_number > last_block_number
319
    ):
320
        raise InvalidBlock
321
322
    parent_header = chain.blocks[
323
        parent_header_number - first_block_number
324
    ].header
306
    parent_header = chain.blocks[-1].header
307
308
    if header.gas_used > header.gas_limit:
309
        raise InvalidBlock
310
311
    expected_base_fee_per_gas = calculate_base_fee_per_gas(
312
        header.gas_limit,
313
        parent_header.gas_limit,
314
        parent_header.gas_used,
315
        parent_header.base_fee_per_gas,
316
    )
317
    if expected_base_fee_per_gas != header.base_fee_per_gas:
318
        raise InvalidBlock
337
338
    parent_has_ommers = parent_header.ommers_hash != EMPTY_OMMER_HASH
319
    if header.timestamp <= parent_header.timestamp:
320
        raise InvalidBlock
321
    if header.number != parent_header.number + Uint(1):
322
        raise InvalidBlock
323
    if len(header.extra_data) > 32:
324
        raise InvalidBlock
345
346
    block_difficulty = calculate_block_difficulty(
347
        header.number,
348
        header.timestamp,
349
        parent_header.timestamp,
350
        parent_header.difficulty,
351
        parent_has_ommers,
352
    )
353
    if header.difficulty != block_difficulty:
325
    if header.difficulty != 0:
326
        raise InvalidBlock
327
    if header.nonce != b"\x00\x00\x00\x00\x00\x00\x00\x00":
328
        raise InvalidBlock
329
    if header.ommers_hash != EMPTY_OMMER_HASH:
330
        raise InvalidBlock
331
332
    block_parent_hash = keccak256(rlp.encode(parent_header))
333
    if header.parent_hash != block_parent_hash:
358
        raise InvalidBlock
359
360
    validate_proof_of_work(header)
334
        raise InvalidBlock

generate_header_hash_for_pow

Generate rlp hash of the header which is to be used for Proof-of-Work verification.

In other words, the PoW artefacts mix_digest and nonce are ignored while calculating this hash.

A particular PoW is valid for a single hash, that hash is computed by this function. The nonce and mix_digest are omitted from this hash because they are being changed by miners in their search for a sufficient proof-of-work.

Parameters

header : The header object for which the hash is to be generated.

Returns

hash : Hash32 The PoW valid rlp hash of the passed in header.

def generate_header_hash_for_pow(header: Header) -> Hash32:
364
    <snip>
387
    header_data_without_pow_artefacts = (
388
        header.parent_hash,
389
        header.ommers_hash,
390
        header.coinbase,
391
        header.state_root,
392
        header.transactions_root,
393
        header.receipt_root,
394
        header.bloom,
395
        header.difficulty,
396
        header.number,
397
        header.gas_limit,
398
        header.gas_used,
399
        header.timestamp,
400
        header.extra_data,
401
        header.base_fee_per_gas,
402
    )
403
404
    return keccak256(rlp.encode(header_data_without_pow_artefacts))

validate_proof_of_work

Validates the Proof of Work constraints.

In order to verify that a miner's proof-of-work is valid for a block, a mix-digest and result are calculated using the hashimoto_light hash function. The mix digest is a hash of the header and the nonce that is passed through and it confirms whether or not proof-of-work was done on the correct block. The result is the actual hash value of the block.

Parameters

header : Header of interest.

def validate_proof_of_work(header: Header) -> None:
408
    <snip>
423
    header_hash = generate_header_hash_for_pow(header)
424
    # TODO: Memoize this somewhere and read from that data instead of
425
    # calculating cache for every block validation.
426
    cache = generate_cache(header.number)
427
    mix_digest, result = hashimoto_light(
428
        header_hash, header.nonce, cache, dataset_size(header.number)
429
    )
430
    if mix_digest != header.mix_digest:
431
        raise InvalidBlock
432
433
    limit = Uint(U256.MAX_VALUE) + Uint(1)
434
    if Uint.from_be_bytes(result) > (limit // header.difficulty):
435
        raise InvalidBlock

check_transaction

Check if the transaction is includable in the block.

Parameters

block_env : The block scoped environment. block_output : The block output for the current block. tx : The transaction. tx_state : The transaction state tracker.

Returns

sender_address : The sender of the transaction. effective_gas_price : The price to charge for gas when the transaction is executed.

Raises

InvalidBlock : If the transaction is not includable. GasUsedExceedsLimitError : If the gas used by the transaction exceeds the block's gas limit. NonceMismatchError : If the nonce of the transaction is not equal to the sender's nonce. InsufficientBalanceError : If the sender's balance is not enough to pay for the transaction. InvalidSenderError : If the transaction is from an address that does not exist anymore. InsufficientMaxFeePerGasError : If the maximum fee per gas is insufficient for the transaction.

def check_transaction(block_env: ethereum.forks.gray_glacier.vm.BlockEnvironmentethereum.forks.paris.vm.BlockEnvironment, ​​block_output: ethereum.forks.gray_glacier.vm.BlockOutputethereum.forks.paris.vm.BlockOutput, ​​tx: Transaction, ​​tx_state: TransactionState) -> Tuple[Address, Uint]:
343
    <snip>
380
    gas_available = block_env.block_gas_limit - block_output.block_gas_used
381
    if tx.gas > gas_available:
382
        raise GasUsedExceedsLimitError("gas used exceeds limit")
383
    tx_chain_id = chain_id(tx)
384
    if tx_chain_id is not None and tx_chain_id != block_env.chain_id:
385
        raise WrongChainIdError(
386
            expected=block_env.chain_id,
387
            actual=tx_chain_id,
388
        )
389
390
    sender_address = recover_sender(tx)
391
    sender_account = get_account(tx_state, sender_address)
392
393
    if isinstance(tx, FeeMarketTransaction):
394
        if tx.max_fee_per_gas < block_env.base_fee_per_gas:
395
            raise InsufficientMaxFeePerGasError(
396
                tx.max_fee_per_gas, block_env.base_fee_per_gas
397
            )
398
399
        priority_fee_per_gas = min(
400
            tx.max_priority_fee_per_gas,
401
            tx.max_fee_per_gas - block_env.base_fee_per_gas,
402
        )
403
        effective_gas_price = priority_fee_per_gas + block_env.base_fee_per_gas
404
        max_gas_fee = tx.gas * tx.max_fee_per_gas
405
    else:
406
        if tx.gas_price < block_env.base_fee_per_gas:
407
            raise InvalidBlock
408
        effective_gas_price = tx.gas_price
409
        max_gas_fee = tx.gas * tx.gas_price
410
411
    if sender_account.nonce > Uint(tx.nonce):
412
        raise NonceMismatchError("nonce too low")
413
    elif sender_account.nonce < Uint(tx.nonce):
414
        raise NonceMismatchError("nonce too high")
415
    if Uint(sender_account.balance) < max_gas_fee + Uint(tx.value):
416
        raise InsufficientBalanceError("insufficient sender balance")
417
    if sender_account.code_hash != EMPTY_CODE_HASH:
418
        raise InvalidSenderError("not EOA")
419
420
    return sender_address, effective_gas_price

make_receipt

Make the receipt for a transaction that was executed.

Parameters

tx : The executed transaction. error : Error in the top level frame of the transaction, if any. cumulative_gas_used : The total gas used so far in the block after the transaction was executed. logs : The logs produced by the transaction.

Returns

receipt : The receipt for the transaction.

def make_receipt(tx: Transaction, ​​error: Optional[EthereumException], ​​cumulative_gas_used: Uint, ​​logs: Tuple[Log, ...]) -> Bytes | Receipt:
429
    <snip>
450
    receipt = Receipt(
451
        succeeded=error is None,
452
        cumulative_gas_used=cumulative_gas_used,
453
        bloom=logs_bloom(logs),
454
        logs=logs,
455
    )
456
457
    return encode_receipt(tx, receipt)

apply_body

Executes a block.

Many of the contents of a block are stored in data structures called tries. There is a transactions trie which is similar to a ledger of the transactions stored in the current block. There is also a receipts trie which stores the results of executing a transaction, like the post state and gas used. This function creates and executes the block that is to be added to the chain.

Parameters

block_env : The block scoped environment. transactions : Transactions included in the block. ommers : Headers of ancestor blocks which are not direct parents (formerly uncles.)

Returns

block_output : The block output for the current block.

def apply_body(block_env: ethereum.forks.gray_glacier.vm.BlockEnvironmentethereum.forks.paris.vm.BlockEnvironment, ​​transactions: Tuple[LegacyTransaction | Bytes, ...], ​​ommers: Tuple[Header, ...]) -> ethereum.forks.gray_glacier.vm.BlockOutputethereum.forks.paris.vm.BlockOutput:
464
    <snip>
487
    block_output = vm.BlockOutput()
488
489
    for i, tx in enumerate(map(decode_transaction, transactions)):
490
        process_transaction(block_env, block_output, tx, Uint(i))
491
597
    pay_rewards(block_env, ommers)
598
492
    return block_output

validate_ommers

Validates the ommers mentioned in the block.

An ommer block is a block that wasn't canonically added to the blockchain because it wasn't validated as fast as the canonical block but was mined at the same time.

To be considered valid, the ommers must adhere to the rules defined in the Ethereum protocol. The maximum amount of ommers is 2 per block and there cannot be duplicate ommers in a block. Many of the other ommer constraints are listed in the in-line comments of this function.

Parameters

ommers : List of ommers mentioned in the current block. block_header: The header of current block. chain : History and current state.

def validate_ommers(ommers: Tuple[Header, ...], ​​block_header: Header, ​​chain: BlockChain) -> None:
605
    <snip>
627
    block_hash = keccak256(rlp.encode(block_header))
628
    if keccak256(rlp.encode(ommers)) != block_header.ommers_hash:
629
        raise InvalidBlock
630
631
    if len(ommers) == 0:
632
        # Nothing to validate
633
        return
634
635
    # Check that each ommer satisfies the constraints of a header
636
    for ommer in ommers:
637
        if Uint(1) > ommer.number or ommer.number >= block_header.number:
638
            raise InvalidBlock
639
        validate_header(chain, ommer)
640
    if len(ommers) > 2:
641
        raise InvalidBlock
642
643
    ommers_hashes = [keccak256(rlp.encode(ommer)) for ommer in ommers]
644
    if len(ommers_hashes) != len(set(ommers_hashes)):
645
        raise InvalidBlock
646
647
    recent_canonical_blocks = chain.blocks[-(MAX_OMMER_DEPTH + Uint(1)) :]
648
    recent_canonical_block_hashes = {
649
        keccak256(rlp.encode(block.header))
650
        for block in recent_canonical_blocks
651
    }
652
    recent_ommers_hashes: Set[Hash32] = set()
653
    for block in recent_canonical_blocks:
654
        recent_ommers_hashes = recent_ommers_hashes.union(
655
            {keccak256(rlp.encode(ommer)) for ommer in block.ommers}
656
        )
657
658
    for ommer_index, ommer in enumerate(ommers):
659
        ommer_hash = ommers_hashes[ommer_index]
660
        if ommer_hash == block_hash:
661
            raise InvalidBlock
662
        if ommer_hash in recent_canonical_block_hashes:
663
            raise InvalidBlock
664
        if ommer_hash in recent_ommers_hashes:
665
            raise InvalidBlock
666
667
        # Ommer age with respect to the current block. For example, an age of
668
        # 1 indicates that the ommer is a sibling of previous block.
669
        ommer_age = block_header.number - ommer.number
670
        if Uint(1) > ommer_age or ommer_age > MAX_OMMER_DEPTH:
671
            raise InvalidBlock
672
        if ommer.parent_hash not in recent_canonical_block_hashes:
673
            raise InvalidBlock
674
        if ommer.parent_hash == block_header.parent_hash:
675
            raise InvalidBlock

pay_rewards

Pay rewards to the block miner as well as the ommers miners.

The miner of the canonical block is rewarded with the predetermined block reward, BLOCK_REWARD, plus a variable award based off of the number of ommer blocks that were mined around the same time, and included in the canonical block's header. An ommer block is a block that wasn't added to the canonical blockchain because it wasn't validated as fast as the accepted block but was mined at the same time. Although not all blocks that are mined are added to the canonical chain, miners are still paid a reward for their efforts. This reward is called an ommer reward and is calculated based on the number associated with the ommer block that they mined.

Parameters

block_env : The block scoped environment. ommers : List of ommers mentioned in the current block.

def pay_rewards(block_env: ethereum.forks.gray_glacier.vm.BlockEnvironment, ​​ommers: Tuple[Header, ...]) -> None:
682
    <snip>
704
    rewards_state = TransactionState(parent=block_env.state)
705
    ommer_count = U256(len(ommers))
706
    miner_reward = BLOCK_REWARD + (ommer_count * (BLOCK_REWARD // U256(32)))
707
    create_ether(rewards_state, block_env.coinbase, miner_reward)
708
709
    for ommer in ommers:
710
        # Ommer age with respect to the current block.
711
        ommer_age = U256(block_env.number - ommer.number)
712
        ommer_miner_reward = ((U256(8) - ommer_age) * BLOCK_REWARD) // U256(8)
713
        create_ether(rewards_state, ommer.coinbase, ommer_miner_reward)
714
715
    incorporate_tx_into_block(rewards_state)

process_transaction

Execute a transaction against the provided environment.

This function processes the actions needed to execute a transaction. It decrements the sender's account balance after calculating the gas fee and refunds them the proper amount after execution. Calling contracts, deploying code, and incrementing nonces are all examples of actions that happen within this function or from a call made within this function.

Accounts that are marked for deletion are processed and destroyed after execution.

Parameters

block_env : Environment for the Ethereum Virtual Machine. block_output : The block output for the current block. tx : Transaction to execute. index: Index of the transaction in the block.

def process_transaction(block_env: ethereum.forks.gray_glacier.vm.BlockEnvironmentethereum.forks.paris.vm.BlockEnvironment, ​​block_output: ethereum.forks.gray_glacier.vm.BlockOutputethereum.forks.paris.vm.BlockOutput, ​​tx: Transaction, ​​index: Uint) -> None:
501
    <snip>
525
    tx_state = TransactionState(parent=block_env.state)
526
527
    trie_set(
528
        block_output.transactions_trie,
529
        rlp.encode(index),
530
        encode_transaction(tx),
531
    )
532
533
    intrinsic_gas = validate_transaction(tx)
534
535
    (
536
        sender,
537
        effective_gas_price,
538
    ) = check_transaction(
539
        block_env=block_env,
540
        block_output=block_output,
541
        tx=tx,
542
        tx_state=tx_state,
543
    )
544
545
    sender_account = get_account(tx_state, sender)
546
547
    effective_gas_fee = tx.gas * effective_gas_price
548
549
    gas = tx.gas - intrinsic_gas
550
    increment_nonce(tx_state, sender)
551
552
    sender_balance_after_gas_fee = (
553
        Uint(sender_account.balance) - effective_gas_fee
554
    )
555
    set_account_balance(tx_state, sender, U256(sender_balance_after_gas_fee))
556
557
    access_list_addresses = set()
558
    access_list_storage_keys = set()
559
    if isinstance(tx, (AccessListTransaction, FeeMarketTransaction)):
560
        for access in tx.access_list:
561
            access_list_addresses.add(access.account)
562
            for slot in access.slots:
563
                access_list_storage_keys.add((access.account, slot))
564
565
    tx_env = vm.TransactionEnvironment(
566
        origin=sender,
567
        gas_price=effective_gas_price,
568
        gas=gas,
569
        access_list_addresses=access_list_addresses,
570
        access_list_storage_keys=access_list_storage_keys,
571
        state=tx_state,
572
        index_in_block=index,
573
        tx_hash=get_transaction_hash(encode_transaction(tx)),
574
    )
575
576
    message = prepare_message(block_env, tx_env, tx)
577
578
    tx_output = process_message_call(message)
579
580
    tx_gas_used_before_refund = tx.gas - tx_output.gas_left
581
    tx_gas_refund = min(
582
        tx_gas_used_before_refund // Uint(5), Uint(tx_output.refund_counter)
583
    )
584
    tx_gas_used_after_refund = tx_gas_used_before_refund - tx_gas_refund
585
    tx_gas_left = tx.gas - tx_gas_used_after_refund
586
    gas_refund_amount = tx_gas_left * effective_gas_price
587
588
    # For non-1559 transactions effective_gas_price == tx.gas_price
589
    priority_fee_per_gas = effective_gas_price - block_env.base_fee_per_gas
590
    transaction_fee = tx_gas_used_after_refund * priority_fee_per_gas
591
592
    # refund gas
593
    create_ether(tx_state, sender, U256(gas_refund_amount))
594
595
    # transfer miner fees
819
    coinbase_balance_after_mining_fee = get_account(
820
        tx_state, block_env.coinbase
821
    ).balance + U256(transaction_fee)
822
    if coinbase_balance_after_mining_fee != 0:
823
        set_account_balance(
824
            tx_state,
825
            block_env.coinbase,
826
            coinbase_balance_after_mining_fee,
827
        )
828
    elif account_exists_and_is_empty(tx_state, block_env.coinbase):
829
        destroy_account(tx_state, block_env.coinbase)
596
    create_ether(tx_state, block_env.coinbase, U256(transaction_fee))
597
598
    for address in tx_output.accounts_to_delete:
599
        destroy_account(tx_state, address)
833
834
    destroy_touched_empty_accounts(tx_state, tx_output.touched_accounts)
600
601
    block_output.block_gas_used += tx_gas_used_after_refund
602
603
    receipt = make_receipt(
604
        tx, tx_output.error, block_output.block_gas_used, tx_output.logs
605
    )
606
607
    receipt_key = rlp.encode(Uint(index))
608
    block_output.receipt_keys += (receipt_key,)
609
610
    trie_set(
611
        block_output.receipts_trie,
612
        receipt_key,
613
        receipt,
614
    )
615
616
    block_output.block_logs += tx_output.logs
617
618
    incorporate_tx_into_block(tx_state)

check_gas_limit

Validates the gas limit for a block.

The bounds of the gas limit, max_adjustment_delta, is set as the quotient of the parent block's gas limit and the LIMIT_ADJUSTMENT_FACTOR. Therefore, if the gas limit that is passed through as a parameter is greater than or equal to the sum of the parent's gas and the adjustment delta then the limit for gas is too high and fails this function's check. Similarly, if the limit is less than or equal to the difference of the parent's gas and the adjustment delta or the predefined LIMIT_MINIMUM then this function's check fails because the gas limit doesn't allow for a sufficient or reasonable amount of gas to be used on a block.

Parameters

gas_limit : Gas limit to validate.

parent_gas_limit : Gas limit of the parent block.

Returns

check : bool True if gas limit constraints are satisfied, False otherwise.

def check_gas_limit(gas_limit: Uint, ​​parent_gas_limit: Uint) -> bool:
622
    <snip>
650
    max_adjustment_delta = parent_gas_limit // GasCosts.LIMIT_ADJUSTMENT_FACTOR
651
    if gas_limit >= parent_gas_limit + max_adjustment_delta:
652
        return False
653
    if gas_limit <= parent_gas_limit - max_adjustment_delta:
654
        return False
655
    if gas_limit < GasCosts.LIMIT_MINIMUM:
656
        return False
657
658
    return True

calculate_block_difficulty

Computes difficulty of a block using its header and parent header.

The difficulty is determined by the time the block was created after its parent. The offset is calculated using the parent block's difficulty, parent_difficulty, and the timestamp between blocks. This offset is then added to the parent difficulty and is stored as the difficulty variable. If the time between the block and its parent is too short, the offset will result in a positive number thus making the sum of parent_difficulty and offset to be a greater value in order to avoid mass forking. But, if the time is long enough, then the offset results in a negative value making the block less difficult than its parent.

The base standard for a block's difficulty is the predefined value set for the genesis block since it has no parent. So, a block can't be less difficult than the genesis block, therefore each block's difficulty is set to the maximum value between the calculated difficulty and the MINIMUM_DIFFICULTY.

Parameters

block_number : Block number of the block. block_timestamp : Timestamp of the block. parent_timestamp : Timestamp of the parent block. parent_difficulty : difficulty of the parent block. parent_has_ommers: does the parent have ommers.

Returns

difficulty : ethereum.base_types.Uint Computed difficulty for a block.

def calculate_block_difficulty(block_number: Uint, ​​block_timestamp: U256, ​​parent_timestamp: U256, ​​parent_difficulty: Uint, ​​parent_has_ommers: bool) -> Uint:
903
    <snip>
942
    offset = (
943
        int(parent_difficulty)
944
        // 2048
945
        * max(
946
            (2 if parent_has_ommers else 1)
947
            - int(block_timestamp - parent_timestamp) // 9,
948
            -99,
949
        )
950
    )
951
    difficulty = int(parent_difficulty) + offset
952
    # Historical Note: The difficulty bomb was not present in Ethereum at the
953
    # start of Frontier, but was added shortly after launch. However since the
954
    # bomb has no effect prior to block 200000 we pretend it existed from
955
    # genesis.
956
    # See https://github.com/ethereum/go-ethereum/pull/1588
957
    num_bomb_periods = ((int(block_number) - BOMB_DELAY_BLOCKS) // 100000) - 2
958
    if num_bomb_periods >= 0:
959
        difficulty += 2**num_bomb_periods
960
961
    # Some clients raise the difficulty to `MINIMUM_DIFFICULTY` prior to adding
962
    # the bomb. This bug does not matter because the difficulty is always much
963
    # greater than `MINIMUM_DIFFICULTY` on Mainnet.
964
    return Uint(max(difficulty, int(MINIMUM_DIFFICULTY)))