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
    if len(recent_blocks) == 0:
131
        return []
132
133
    recent_block_hashes = []
134
135
    for block in recent_blocks:
136
        prev_block_hash = block.header.parent_hash
137
        recent_block_hashes.append(prev_block_hash)
138
139
    # We are computing the hash only for the most recent block and not for
140
    # the rest of the blocks as they have successors which have the hash of
141
    # the current block as parent hash.
142
    most_recent_block_hash = keccak256(rlp.encode(recent_blocks[-1].header))
143
    recent_block_hashes.append(most_recent_block_hash)
144
145
    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:
149
    <snip>
171
    validate_header(chain, block.header)
179
    validate_ommers(block.ommers, block.header, chain)
172
    if block.ommers != ():
173
        raise InvalidBlock
174
175
    block_state = BlockState(pre_state=chain.state)
176
177
    block_env = vm.BlockEnvironment(
178
        chain_id=chain.chain_id,
179
        state=block_state,
180
        block_gas_limit=block.header.gas_limit,
181
        block_hashes=get_last_256_block_hashes(chain),
182
        coinbase=block.header.coinbase,
183
        number=block.header.number,
184
        base_fee_per_gas=block.header.base_fee_per_gas,
185
        time=block.header.timestamp,
192
        difficulty=block.header.difficulty,
186
        prev_randao=block.header.prev_randao,
187
    )
188
189
    block_output = apply_body(
190
        block_env=block_env,
191
        transactions=block.transactions,
198
        ommers=block.ommers,
192
    )
193
    block_diff = extract_block_diff(block_state)
194
    block_state_root = chain.state.compute_state_root(block_diff)
195
    transactions_root = root(block_output.transactions_trie)
196
    receipt_root = root(block_output.receipts_trie)
197
    block_logs_bloom = logs_bloom(block_output.block_logs)
198
199
    if block_output.block_gas_used != block.header.gas_used:
200
        raise InvalidBlock(
201
            f"{block_output.block_gas_used} != {block.header.gas_used}"
202
        )
203
    if transactions_root != block.header.transactions_root:
204
        raise InvalidBlock
205
    if block_state_root != block.header.state_root:
206
        raise InvalidBlock
207
    if receipt_root != block.header.receipt_root:
208
        raise InvalidBlock
209
    if block_logs_bloom != block.header.bloom:
210
        raise InvalidBlock
211
212
    apply_changes_to_state(chain.state, block_diff)
213
    chain.blocks.append(block)
214
    if len(chain.blocks) > 255:
215
        # Real clients have to store more blocks to deal with reorgs, but the
216
        # protocol only requires the last 255
217
        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:
226
    <snip>
246
    parent_gas_target = parent_gas_limit // ELASTICITY_MULTIPLIER
247
    if not check_gas_limit(block_gas_limit, parent_gas_limit):
248
        raise InvalidBlock
249
250
    if parent_gas_used == parent_gas_target:
251
        expected_base_fee_per_gas = parent_base_fee_per_gas
252
    elif parent_gas_used > parent_gas_target:
253
        gas_used_delta = parent_gas_used - parent_gas_target
254
255
        parent_fee_gas_delta = parent_base_fee_per_gas * gas_used_delta
256
        target_fee_gas_delta = parent_fee_gas_delta // parent_gas_target
257
258
        base_fee_per_gas_delta = max(
259
            target_fee_gas_delta // BASE_FEE_MAX_CHANGE_DENOMINATOR,
260
            Uint(1),
261
        )
262
263
        expected_base_fee_per_gas = (
264
            parent_base_fee_per_gas + base_fee_per_gas_delta
265
        )
266
    else:
267
        gas_used_delta = parent_gas_target - parent_gas_used
268
269
        parent_fee_gas_delta = parent_base_fee_per_gas * gas_used_delta
270
        target_fee_gas_delta = parent_fee_gas_delta // parent_gas_target
271
272
        base_fee_per_gas_delta = (
273
            target_fee_gas_delta // BASE_FEE_MAX_CHANGE_DENOMINATOR
274
        )
275
276
        expected_base_fee_per_gas = (
277
            parent_base_fee_per_gas - base_fee_per_gas_delta
278
        )
279
280
    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:
284
    <snip>
302
    if header.number < Uint(1):
303
        raise InvalidBlock
311
    parent_header_number = header.number - Uint(1)
312
    first_block_number = chain.blocks[0].header.number
313
    last_block_number = chain.blocks[-1].header.number
304
315
    if (
316
        parent_header_number < first_block_number
317
        or parent_header_number > last_block_number
318
    ):
319
        raise InvalidBlock
320
321
    parent_header = chain.blocks[
322
        parent_header_number - first_block_number
323
    ].header
305
    parent_header = chain.blocks[-1].header
306
307
    if header.gas_used > header.gas_limit:
308
        raise InvalidBlock
309
310
    expected_base_fee_per_gas = calculate_base_fee_per_gas(
311
        header.gas_limit,
312
        parent_header.gas_limit,
313
        parent_header.gas_used,
314
        parent_header.base_fee_per_gas,
315
    )
316
    if expected_base_fee_per_gas != header.base_fee_per_gas:
317
        raise InvalidBlock
336
337
    parent_has_ommers = parent_header.ommers_hash != EMPTY_OMMER_HASH
318
    if header.timestamp <= parent_header.timestamp:
319
        raise InvalidBlock
320
    if header.number != parent_header.number + Uint(1):
321
        raise InvalidBlock
322
    if len(header.extra_data) > 32:
323
        raise InvalidBlock
344
345
    block_difficulty = calculate_block_difficulty(
346
        header.number,
347
        header.timestamp,
348
        parent_header.timestamp,
349
        parent_header.difficulty,
350
        parent_has_ommers,
351
    )
352
    if header.difficulty != block_difficulty:
324
    if header.difficulty != 0:
325
        raise InvalidBlock
326
    if header.nonce != b"\x00\x00\x00\x00\x00\x00\x00\x00":
327
        raise InvalidBlock
328
    if header.ommers_hash != EMPTY_OMMER_HASH:
329
        raise InvalidBlock
330
331
    block_parent_hash = keccak256(rlp.encode(parent_header))
332
    if header.parent_hash != block_parent_hash:
357
        raise InvalidBlock
358
359
    validate_proof_of_work(header)
333
        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:
363
    <snip>
386
    header_data_without_pow_artefacts = (
387
        header.parent_hash,
388
        header.ommers_hash,
389
        header.coinbase,
390
        header.state_root,
391
        header.transactions_root,
392
        header.receipt_root,
393
        header.bloom,
394
        header.difficulty,
395
        header.number,
396
        header.gas_limit,
397
        header.gas_used,
398
        header.timestamp,
399
        header.extra_data,
400
        header.base_fee_per_gas,
401
    )
402
403
    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:
407
    <snip>
422
    header_hash = generate_header_hash_for_pow(header)
423
    # TODO: Memoize this somewhere and read from that data instead of
424
    # calculating cache for every block validation.
425
    cache = generate_cache(header.number)
426
    mix_digest, result = hashimoto_light(
427
        header_hash, header.nonce, cache, dataset_size(header.number)
428
    )
429
    if mix_digest != header.mix_digest:
430
        raise InvalidBlock
431
432
    limit = Uint(U256.MAX_VALUE) + Uint(1)
433
    if Uint.from_be_bytes(result) > (limit // header.difficulty):
434
        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]:
342
    <snip>
379
    gas_available = block_env.block_gas_limit - block_output.block_gas_used
380
    if tx.gas > gas_available:
381
        raise GasUsedExceedsLimitError("gas used exceeds limit")
382
    tx_chain_id = chain_id(tx)
383
    if tx_chain_id is not None and tx_chain_id != block_env.chain_id:
384
        raise WrongChainIdError(
385
            expected=block_env.chain_id,
386
            actual=tx_chain_id,
387
        )
388
389
    sender_address = recover_sender(tx)
390
    sender_account = get_account(tx_state, sender_address)
391
392
    if isinstance(tx, FeeMarketTransaction):
393
        if tx.max_fee_per_gas < block_env.base_fee_per_gas:
394
            raise InsufficientMaxFeePerGasError(
395
                tx.max_fee_per_gas, block_env.base_fee_per_gas
396
            )
397
398
        priority_fee_per_gas = min(
399
            tx.max_priority_fee_per_gas,
400
            tx.max_fee_per_gas - block_env.base_fee_per_gas,
401
        )
402
        effective_gas_price = priority_fee_per_gas + block_env.base_fee_per_gas
403
        max_gas_fee = tx.gas * tx.max_fee_per_gas
404
    else:
405
        if tx.gas_price < block_env.base_fee_per_gas:
406
            raise InvalidBlock
407
        effective_gas_price = tx.gas_price
408
        max_gas_fee = tx.gas * tx.gas_price
409
410
    if sender_account.nonce > Uint(tx.nonce):
411
        raise NonceMismatchError("nonce too low")
412
    elif sender_account.nonce < Uint(tx.nonce):
413
        raise NonceMismatchError("nonce too high")
414
    if Uint(sender_account.balance) < max_gas_fee + Uint(tx.value):
415
        raise InsufficientBalanceError("insufficient sender balance")
416
    if sender_account.code_hash != EMPTY_CODE_HASH:
417
        raise InvalidSenderError("not EOA")
418
419
    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:
428
    <snip>
449
    receipt = Receipt(
450
        succeeded=error is None,
451
        cumulative_gas_used=cumulative_gas_used,
452
        bloom=logs_bloom(logs),
453
        logs=logs,
454
    )
455
456
    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:
463
    <snip>
486
    block_output = vm.BlockOutput()
487
488
    for i, tx in enumerate(map(decode_transaction, transactions)):
489
        process_transaction(block_env, block_output, tx, Uint(i))
490
596
    pay_rewards(block_env, ommers)
597
491
    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:
604
    <snip>
626
    block_hash = keccak256(rlp.encode(block_header))
627
    if keccak256(rlp.encode(ommers)) != block_header.ommers_hash:
628
        raise InvalidBlock
629
630
    if len(ommers) == 0:
631
        # Nothing to validate
632
        return
633
634
    # Check that each ommer satisfies the constraints of a header
635
    for ommer in ommers:
636
        if Uint(1) > ommer.number or ommer.number >= block_header.number:
637
            raise InvalidBlock
638
        validate_header(chain, ommer)
639
    if len(ommers) > 2:
640
        raise InvalidBlock
641
642
    ommers_hashes = [keccak256(rlp.encode(ommer)) for ommer in ommers]
643
    if len(ommers_hashes) != len(set(ommers_hashes)):
644
        raise InvalidBlock
645
646
    recent_canonical_blocks = chain.blocks[-(MAX_OMMER_DEPTH + Uint(1)) :]
647
    recent_canonical_block_hashes = {
648
        keccak256(rlp.encode(block.header))
649
        for block in recent_canonical_blocks
650
    }
651
    recent_ommers_hashes: Set[Hash32] = set()
652
    for block in recent_canonical_blocks:
653
        recent_ommers_hashes = recent_ommers_hashes.union(
654
            {keccak256(rlp.encode(ommer)) for ommer in block.ommers}
655
        )
656
657
    for ommer_index, ommer in enumerate(ommers):
658
        ommer_hash = ommers_hashes[ommer_index]
659
        if ommer_hash == block_hash:
660
            raise InvalidBlock
661
        if ommer_hash in recent_canonical_block_hashes:
662
            raise InvalidBlock
663
        if ommer_hash in recent_ommers_hashes:
664
            raise InvalidBlock
665
666
        # Ommer age with respect to the current block. For example, an age of
667
        # 1 indicates that the ommer is a sibling of previous block.
668
        ommer_age = block_header.number - ommer.number
669
        if Uint(1) > ommer_age or ommer_age > MAX_OMMER_DEPTH:
670
            raise InvalidBlock
671
        if ommer.parent_hash not in recent_canonical_block_hashes:
672
            raise InvalidBlock
673
        if ommer.parent_hash == block_header.parent_hash:
674
            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:
681
    <snip>
703
    rewards_state = TransactionState(parent=block_env.state)
704
    ommer_count = U256(len(ommers))
705
    miner_reward = BLOCK_REWARD + (ommer_count * (BLOCK_REWARD // U256(32)))
706
    create_ether(rewards_state, block_env.coinbase, miner_reward)
707
708
    for ommer in ommers:
709
        # Ommer age with respect to the current block.
710
        ommer_age = U256(block_env.number - ommer.number)
711
        ommer_miner_reward = ((U256(8) - ommer_age) * BLOCK_REWARD) // U256(8)
712
        create_ether(rewards_state, ommer.coinbase, ommer_miner_reward)
713
714
    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:
500
    <snip>
524
    tx_state = TransactionState(parent=block_env.state)
525
526
    trie_set(
527
        block_output.transactions_trie,
528
        rlp.encode(index),
529
        encode_transaction(tx),
530
    )
531
532
    intrinsic_gas = validate_transaction(tx)
533
534
    (
535
        sender,
536
        effective_gas_price,
537
    ) = check_transaction(
538
        block_env=block_env,
539
        block_output=block_output,
540
        tx=tx,
541
        tx_state=tx_state,
542
    )
543
544
    sender_account = get_account(tx_state, sender)
545
546
    effective_gas_fee = tx.gas * effective_gas_price
547
548
    gas = tx.gas - intrinsic_gas
549
    increment_nonce(tx_state, sender)
550
551
    sender_balance_after_gas_fee = (
552
        Uint(sender_account.balance) - effective_gas_fee
553
    )
554
    set_account_balance(tx_state, sender, U256(sender_balance_after_gas_fee))
555
556
    access_list_addresses = set()
557
    access_list_storage_keys = set()
558
    if isinstance(tx, (AccessListTransaction, FeeMarketTransaction)):
559
        for access in tx.access_list:
560
            access_list_addresses.add(access.account)
561
            for slot in access.slots:
562
                access_list_storage_keys.add((access.account, slot))
563
564
    tx_env = vm.TransactionEnvironment(
565
        origin=sender,
566
        gas_price=effective_gas_price,
567
        gas=gas,
568
        access_list_addresses=access_list_addresses,
569
        access_list_storage_keys=access_list_storage_keys,
570
        state=tx_state,
571
        index_in_block=index,
572
        tx_hash=get_transaction_hash(encode_transaction(tx)),
573
    )
574
575
    message = prepare_message(block_env, tx_env, tx)
576
577
    tx_output = process_message_call(message)
578
579
    tx_gas_used_before_refund = tx.gas - tx_output.gas_left
580
    tx_gas_refund = min(
581
        tx_gas_used_before_refund // Uint(5), Uint(tx_output.refund_counter)
582
    )
583
    tx_gas_used_after_refund = tx_gas_used_before_refund - tx_gas_refund
584
    tx_gas_left = tx.gas - tx_gas_used_after_refund
585
    gas_refund_amount = tx_gas_left * effective_gas_price
586
587
    # For non-1559 transactions effective_gas_price == tx.gas_price
588
    priority_fee_per_gas = effective_gas_price - block_env.base_fee_per_gas
589
    transaction_fee = tx_gas_used_after_refund * priority_fee_per_gas
590
591
    # refund gas
592
    create_ether(tx_state, sender, U256(gas_refund_amount))
593
594
    # transfer miner fees
818
    coinbase_balance_after_mining_fee = get_account(
819
        tx_state, block_env.coinbase
820
    ).balance + U256(transaction_fee)
821
    if coinbase_balance_after_mining_fee != 0:
822
        set_account_balance(
823
            tx_state,
824
            block_env.coinbase,
825
            coinbase_balance_after_mining_fee,
826
        )
827
    elif account_exists_and_is_empty(tx_state, block_env.coinbase):
828
        destroy_account(tx_state, block_env.coinbase)
595
    create_ether(tx_state, block_env.coinbase, U256(transaction_fee))
596
597
    for address in tx_output.accounts_to_delete:
598
        destroy_account(tx_state, address)
832
833
    destroy_touched_empty_accounts(tx_state, tx_output.touched_accounts)
599
600
    block_output.block_gas_used += tx_gas_used_after_refund
601
602
    receipt = make_receipt(
603
        tx, tx_output.error, block_output.block_gas_used, tx_output.logs
604
    )
605
606
    receipt_key = rlp.encode(Uint(index))
607
    block_output.receipt_keys += (receipt_key,)
608
609
    trie_set(
610
        block_output.receipts_trie,
611
        receipt_key,
612
        receipt,
613
    )
614
615
    block_output.block_logs += tx_output.logs
616
617
    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:
621
    <snip>
649
    max_adjustment_delta = parent_gas_limit // GasCosts.LIMIT_ADJUSTMENT_FACTOR
650
    if gas_limit >= parent_gas_limit + max_adjustment_delta:
651
        return False
652
    if gas_limit <= parent_gas_limit - max_adjustment_delta:
653
        return False
654
    if gas_limit < GasCosts.LIMIT_MINIMUM:
655
        return False
656
657
    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:
902
    <snip>
941
    offset = (
942
        int(parent_difficulty)
943
        // 2048
944
        * max(
945
            (2 if parent_has_ommers else 1)
946
            - int(block_timestamp - parent_timestamp) // 9,
947
            -99,
948
        )
949
    )
950
    difficulty = int(parent_difficulty) + offset
951
    # Historical Note: The difficulty bomb was not present in Ethereum at the
952
    # start of Frontier, but was added shortly after launch. However since the
953
    # bomb has no effect prior to block 200000 we pretend it existed from
954
    # genesis.
955
    # See https://github.com/ethereum/go-ethereum/pull/1588
956
    num_bomb_periods = ((int(block_number) - BOMB_DELAY_BLOCKS) // 100000) - 2
957
    if num_bomb_periods >= 0:
958
        difficulty += 2**num_bomb_periods
959
960
    # Some clients raise the difficulty to `MINIMUM_DIFFICULTY` prior to adding
961
    # the bomb. This bug does not matter because the difficulty is always much
962
    # greater than `MINIMUM_DIFFICULTY` on Mainnet.
963
    return Uint(max(difficulty, int(MINIMUM_DIFFICULTY)))