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

68
BLOCK_REWARD = U256(2 * 10**18)

BASE_FEE_MAX_CHANGE_DENOMINATOR

65
BASE_FEE_MAX_CHANGE_DENOMINATOR = Uint(8)

ELASTICITY_MULTIPLIER

66
ELASTICITY_MULTIPLIER = Uint(2)

MINIMUM_DIFFICULTY

71
MINIMUM_DIFFICULTY = Uint(131072)

MAX_OMMER_DEPTH

72
MAX_OMMER_DEPTH = Uint(6)

BOMB_DELAY_BLOCKS

73
BOMB_DELAY_BLOCKS = 11400000

EMPTY_OMMER_HASH

67
EMPTY_OMMER_HASH = keccak256(rlp.encode([]))

BlockChain

History and current state of the block chain.

70
@final
71
@dataclass
class BlockChain:

blocks

77
    blocks: List[Block]

state

78
    state: State

chain_id

79
    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:
83
    <snip>
102
    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]:
106
    <snip>
126
    recent_blocks = chain.blocks[-255:]
127
    if len(recent_blocks) == 0:
128
        return []
129
130
    recent_block_hashes = []
131
132
    for block in recent_blocks:
133
        prev_block_hash = block.header.parent_hash
134
        recent_block_hashes.append(prev_block_hash)
135
136
    # We are computing the hash only for the most recent block and not for
137
    # the rest of the blocks as they have successors which have the hash of
138
    # the current block as parent hash.
139
    most_recent_block_hash = keccak256(rlp.encode(recent_blocks[-1].header))
140
    recent_block_hashes.append(most_recent_block_hash)
141
142
    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:
146
    <snip>
168
    validate_header(chain, block.header)
176
    validate_ommers(block.ommers, block.header, chain)
169
    if block.ommers != ():
170
        raise InvalidBlock
171
172
    block_state = BlockState(pre_state=chain.state)
173
174
    block_env = vm.BlockEnvironment(
175
        chain_id=chain.chain_id,
176
        state=block_state,
177
        block_gas_limit=block.header.gas_limit,
178
        block_hashes=get_last_256_block_hashes(chain),
179
        coinbase=block.header.coinbase,
180
        number=block.header.number,
181
        base_fee_per_gas=block.header.base_fee_per_gas,
182
        time=block.header.timestamp,
189
        difficulty=block.header.difficulty,
183
        prev_randao=block.header.prev_randao,
184
    )
185
186
    block_output = apply_body(
187
        block_env=block_env,
188
        transactions=block.transactions,
195
        ommers=block.ommers,
189
    )
190
    block_diff = extract_block_diff(block_state)
191
    block_state_root = chain.state.compute_state_root(block_diff)
192
    transactions_root = root(block_output.transactions_trie)
193
    receipt_root = root(block_output.receipts_trie)
194
    block_logs_bloom = logs_bloom(block_output.block_logs)
195
196
    if block_output.block_gas_used != block.header.gas_used:
197
        raise InvalidBlock(
198
            f"{block_output.block_gas_used} != {block.header.gas_used}"
199
        )
200
    if transactions_root != block.header.transactions_root:
201
        raise InvalidBlock
202
    if block_state_root != block.header.state_root:
203
        raise InvalidBlock
204
    if receipt_root != block.header.receipt_root:
205
        raise InvalidBlock
206
    if block_logs_bloom != block.header.bloom:
207
        raise InvalidBlock
208
209
    apply_changes_to_state(chain.state, block_diff)
210
    chain.blocks.append(block)
211
    if len(chain.blocks) > 255:
212
        # Real clients have to store more blocks to deal with reorgs, but the
213
        # protocol only requires the last 255
214
        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:
223
    <snip>
243
    parent_gas_target = parent_gas_limit // ELASTICITY_MULTIPLIER
244
    if not check_gas_limit(block_gas_limit, parent_gas_limit):
245
        raise InvalidBlock
246
247
    if parent_gas_used == parent_gas_target:
248
        expected_base_fee_per_gas = parent_base_fee_per_gas
249
    elif parent_gas_used > parent_gas_target:
250
        gas_used_delta = parent_gas_used - parent_gas_target
251
252
        parent_fee_gas_delta = parent_base_fee_per_gas * gas_used_delta
253
        target_fee_gas_delta = parent_fee_gas_delta // parent_gas_target
254
255
        base_fee_per_gas_delta = max(
256
            target_fee_gas_delta // BASE_FEE_MAX_CHANGE_DENOMINATOR,
257
            Uint(1),
258
        )
259
260
        expected_base_fee_per_gas = (
261
            parent_base_fee_per_gas + base_fee_per_gas_delta
262
        )
263
    else:
264
        gas_used_delta = parent_gas_target - parent_gas_used
265
266
        parent_fee_gas_delta = parent_base_fee_per_gas * gas_used_delta
267
        target_fee_gas_delta = parent_fee_gas_delta // parent_gas_target
268
269
        base_fee_per_gas_delta = (
270
            target_fee_gas_delta // BASE_FEE_MAX_CHANGE_DENOMINATOR
271
        )
272
273
        expected_base_fee_per_gas = (
274
            parent_base_fee_per_gas - base_fee_per_gas_delta
275
        )
276
277
    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:
281
    <snip>
299
    if header.number < Uint(1):
300
        raise InvalidBlock
308
    parent_header_number = header.number - Uint(1)
309
    first_block_number = chain.blocks[0].header.number
310
    last_block_number = chain.blocks[-1].header.number
301
312
    if (
313
        parent_header_number < first_block_number
314
        or parent_header_number > last_block_number
315
    ):
316
        raise InvalidBlock
317
318
    parent_header = chain.blocks[
319
        parent_header_number - first_block_number
320
    ].header
302
    parent_header = chain.blocks[-1].header
303
304
    if header.gas_used > header.gas_limit:
305
        raise InvalidBlock
306
307
    expected_base_fee_per_gas = calculate_base_fee_per_gas(
308
        header.gas_limit,
309
        parent_header.gas_limit,
310
        parent_header.gas_used,
311
        parent_header.base_fee_per_gas,
312
    )
313
    if expected_base_fee_per_gas != header.base_fee_per_gas:
314
        raise InvalidBlock
333
334
    parent_has_ommers = parent_header.ommers_hash != EMPTY_OMMER_HASH
315
    if header.timestamp <= parent_header.timestamp:
316
        raise InvalidBlock
317
    if header.number != parent_header.number + Uint(1):
318
        raise InvalidBlock
319
    if len(header.extra_data) > 32:
320
        raise InvalidBlock
341
342
    block_difficulty = calculate_block_difficulty(
343
        header.number,
344
        header.timestamp,
345
        parent_header.timestamp,
346
        parent_header.difficulty,
347
        parent_has_ommers,
348
    )
349
    if header.difficulty != block_difficulty:
321
    if header.difficulty != 0:
322
        raise InvalidBlock
323
    if header.nonce != b"\x00\x00\x00\x00\x00\x00\x00\x00":
324
        raise InvalidBlock
325
    if header.ommers_hash != EMPTY_OMMER_HASH:
326
        raise InvalidBlock
327
328
    block_parent_hash = keccak256(rlp.encode(parent_header))
329
    if header.parent_hash != block_parent_hash:
354
        raise InvalidBlock
355
356
    validate_proof_of_work(header)
330
        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:
360
    <snip>
383
    header_data_without_pow_artefacts = (
384
        header.parent_hash,
385
        header.ommers_hash,
386
        header.coinbase,
387
        header.state_root,
388
        header.transactions_root,
389
        header.receipt_root,
390
        header.bloom,
391
        header.difficulty,
392
        header.number,
393
        header.gas_limit,
394
        header.gas_used,
395
        header.timestamp,
396
        header.extra_data,
397
        header.base_fee_per_gas,
398
    )
399
400
    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:
404
    <snip>
419
    header_hash = generate_header_hash_for_pow(header)
420
    # TODO: Memoize this somewhere and read from that data instead of
421
    # calculating cache for every block validation.
422
    cache = generate_cache(header.number)
423
    mix_digest, result = hashimoto_light(
424
        header_hash, header.nonce, cache, dataset_size(header.number)
425
    )
426
    if mix_digest != header.mix_digest:
427
        raise InvalidBlock
428
429
    limit = Uint(U256.MAX_VALUE) + Uint(1)
430
    if Uint.from_be_bytes(result) > (limit // header.difficulty):
431
        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]:
339
    <snip>
376
    gas_available = block_env.block_gas_limit - block_output.block_gas_used
377
    if tx.gas > gas_available:
378
        raise GasUsedExceedsLimitError("gas used exceeds limit")
379
    tx_chain_id = chain_id(tx)
380
    if tx_chain_id is not None and tx_chain_id != block_env.chain_id:
381
        raise WrongChainIdError(
382
            expected=block_env.chain_id,
383
            actual=tx_chain_id,
384
        )
385
386
    sender_address = recover_sender(tx)
387
    sender_account = get_account(tx_state, sender_address)
388
389
    if isinstance(tx, FeeMarketTransaction):
390
        if tx.max_fee_per_gas < block_env.base_fee_per_gas:
391
            raise InsufficientMaxFeePerGasError(
392
                tx.max_fee_per_gas, block_env.base_fee_per_gas
393
            )
394
395
        priority_fee_per_gas = min(
396
            tx.max_priority_fee_per_gas,
397
            tx.max_fee_per_gas - block_env.base_fee_per_gas,
398
        )
399
        effective_gas_price = priority_fee_per_gas + block_env.base_fee_per_gas
400
        max_gas_fee = tx.gas * tx.max_fee_per_gas
401
    else:
402
        if tx.gas_price < block_env.base_fee_per_gas:
403
            raise InvalidBlock
404
        effective_gas_price = tx.gas_price
405
        max_gas_fee = tx.gas * tx.gas_price
406
407
    if sender_account.nonce > Uint(tx.nonce):
408
        raise NonceMismatchError("nonce too low")
409
    elif sender_account.nonce < Uint(tx.nonce):
410
        raise NonceMismatchError("nonce too high")
411
    if Uint(sender_account.balance) < max_gas_fee + Uint(tx.value):
412
        raise InsufficientBalanceError("insufficient sender balance")
413
    if sender_account.code_hash != EMPTY_CODE_HASH:
414
        raise InvalidSenderError("not EOA")
415
416
    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:
425
    <snip>
446
    receipt = Receipt(
447
        succeeded=error is None,
448
        cumulative_gas_used=cumulative_gas_used,
449
        bloom=logs_bloom(logs),
450
        logs=logs,
451
    )
452
453
    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:
460
    <snip>
483
    block_output = vm.BlockOutput()
484
485
    for i, tx in enumerate(map(decode_transaction, transactions)):
486
        process_transaction(block_env, block_output, tx, Uint(i))
487
593
    pay_rewards(block_env, ommers)
594
488
    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:
601
    <snip>
623
    block_hash = keccak256(rlp.encode(block_header))
624
    if keccak256(rlp.encode(ommers)) != block_header.ommers_hash:
625
        raise InvalidBlock
626
627
    if len(ommers) == 0:
628
        # Nothing to validate
629
        return
630
631
    # Check that each ommer satisfies the constraints of a header
632
    for ommer in ommers:
633
        if Uint(1) > ommer.number or ommer.number >= block_header.number:
634
            raise InvalidBlock
635
        validate_header(chain, ommer)
636
    if len(ommers) > 2:
637
        raise InvalidBlock
638
639
    ommers_hashes = [keccak256(rlp.encode(ommer)) for ommer in ommers]
640
    if len(ommers_hashes) != len(set(ommers_hashes)):
641
        raise InvalidBlock
642
643
    recent_canonical_blocks = chain.blocks[-(MAX_OMMER_DEPTH + Uint(1)) :]
644
    recent_canonical_block_hashes = {
645
        keccak256(rlp.encode(block.header))
646
        for block in recent_canonical_blocks
647
    }
648
    recent_ommers_hashes: Set[Hash32] = set()
649
    for block in recent_canonical_blocks:
650
        recent_ommers_hashes = recent_ommers_hashes.union(
651
            {keccak256(rlp.encode(ommer)) for ommer in block.ommers}
652
        )
653
654
    for ommer_index, ommer in enumerate(ommers):
655
        ommer_hash = ommers_hashes[ommer_index]
656
        if ommer_hash == block_hash:
657
            raise InvalidBlock
658
        if ommer_hash in recent_canonical_block_hashes:
659
            raise InvalidBlock
660
        if ommer_hash in recent_ommers_hashes:
661
            raise InvalidBlock
662
663
        # Ommer age with respect to the current block. For example, an age of
664
        # 1 indicates that the ommer is a sibling of previous block.
665
        ommer_age = block_header.number - ommer.number
666
        if Uint(1) > ommer_age or ommer_age > MAX_OMMER_DEPTH:
667
            raise InvalidBlock
668
        if ommer.parent_hash not in recent_canonical_block_hashes:
669
            raise InvalidBlock
670
        if ommer.parent_hash == block_header.parent_hash:
671
            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:
678
    <snip>
700
    rewards_state = TransactionState(parent=block_env.state)
701
    ommer_count = U256(len(ommers))
702
    miner_reward = BLOCK_REWARD + (ommer_count * (BLOCK_REWARD // U256(32)))
703
    create_ether(rewards_state, block_env.coinbase, miner_reward)
704
705
    for ommer in ommers:
706
        # Ommer age with respect to the current block.
707
        ommer_age = U256(block_env.number - ommer.number)
708
        ommer_miner_reward = ((U256(8) - ommer_age) * BLOCK_REWARD) // U256(8)
709
        create_ether(rewards_state, ommer.coinbase, ommer_miner_reward)
710
711
    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:
497
    <snip>
521
    tx_state = TransactionState(parent=block_env.state)
522
523
    trie_set(
524
        block_output.transactions_trie,
525
        rlp.encode(index),
526
        encode_transaction(tx),
527
    )
528
529
    intrinsic_gas = validate_transaction(tx)
530
531
    (
532
        sender,
533
        effective_gas_price,
534
    ) = check_transaction(
535
        block_env=block_env,
536
        block_output=block_output,
537
        tx=tx,
538
        tx_state=tx_state,
539
    )
540
541
    sender_account = get_account(tx_state, sender)
542
543
    effective_gas_fee = tx.gas * effective_gas_price
544
545
    gas = tx.gas - intrinsic_gas
546
    increment_nonce(tx_state, sender)
547
548
    sender_balance_after_gas_fee = (
549
        Uint(sender_account.balance) - effective_gas_fee
550
    )
551
    set_account_balance(tx_state, sender, U256(sender_balance_after_gas_fee))
552
553
    access_list_addresses = set()
554
    access_list_storage_keys = set()
555
    if isinstance(tx, (AccessListTransaction, FeeMarketTransaction)):
556
        for access in tx.access_list:
557
            access_list_addresses.add(access.account)
558
            for slot in access.slots:
559
                access_list_storage_keys.add((access.account, slot))
560
561
    tx_env = vm.TransactionEnvironment(
562
        origin=sender,
563
        gas_price=effective_gas_price,
564
        gas=gas,
565
        access_list_addresses=access_list_addresses,
566
        access_list_storage_keys=access_list_storage_keys,
567
        state=tx_state,
568
        index_in_block=index,
569
        tx_hash=get_transaction_hash(encode_transaction(tx)),
570
    )
571
572
    message = prepare_message(block_env, tx_env, tx)
573
574
    tx_output = process_message_call(message)
575
576
    tx_gas_used_before_refund = tx.gas - tx_output.gas_left
577
    tx_gas_refund = min(
578
        tx_gas_used_before_refund // Uint(5), Uint(tx_output.refund_counter)
579
    )
580
    tx_gas_used_after_refund = tx_gas_used_before_refund - tx_gas_refund
581
    tx_gas_left = tx.gas - tx_gas_used_after_refund
582
    gas_refund_amount = tx_gas_left * effective_gas_price
583
584
    # For non-1559 transactions effective_gas_price == tx.gas_price
585
    priority_fee_per_gas = effective_gas_price - block_env.base_fee_per_gas
586
    transaction_fee = tx_gas_used_after_refund * priority_fee_per_gas
587
588
    # refund gas
589
    create_ether(tx_state, sender, U256(gas_refund_amount))
590
591
    # transfer miner fees
815
    coinbase_balance_after_mining_fee = get_account(
816
        tx_state, block_env.coinbase
817
    ).balance + U256(transaction_fee)
818
    if coinbase_balance_after_mining_fee != 0:
819
        set_account_balance(
820
            tx_state,
821
            block_env.coinbase,
822
            coinbase_balance_after_mining_fee,
823
        )
824
    elif account_exists_and_is_empty(tx_state, block_env.coinbase):
825
        destroy_account(tx_state, block_env.coinbase)
592
    create_ether(tx_state, block_env.coinbase, U256(transaction_fee))
593
594
    for address in tx_output.accounts_to_delete:
595
        destroy_account(tx_state, address)
829
830
    destroy_touched_empty_accounts(tx_state, tx_output.touched_accounts)
596
597
    block_output.block_gas_used += tx_gas_used_after_refund
598
599
    receipt = make_receipt(
600
        tx, tx_output.error, block_output.block_gas_used, tx_output.logs
601
    )
602
603
    receipt_key = rlp.encode(Uint(index))
604
    block_output.receipt_keys += (receipt_key,)
605
606
    trie_set(
607
        block_output.receipts_trie,
608
        receipt_key,
609
        receipt,
610
    )
611
612
    block_output.block_logs += tx_output.logs
613
614
    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:
618
    <snip>
646
    max_adjustment_delta = parent_gas_limit // GasCosts.LIMIT_ADJUSTMENT_FACTOR
647
    if gas_limit >= parent_gas_limit + max_adjustment_delta:
648
        return False
649
    if gas_limit <= parent_gas_limit - max_adjustment_delta:
650
        return False
651
    if gas_limit < GasCosts.LIMIT_MINIMUM:
652
        return False
653
654
    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:
899
    <snip>
938
    offset = (
939
        int(parent_difficulty)
940
        // 2048
941
        * max(
942
            (2 if parent_has_ommers else 1)
943
            - int(block_timestamp - parent_timestamp) // 9,
944
            -99,
945
        )
946
    )
947
    difficulty = int(parent_difficulty) + offset
948
    # Historical Note: The difficulty bomb was not present in Ethereum at the
949
    # start of Frontier, but was added shortly after launch. However since the
950
    # bomb has no effect prior to block 200000 we pretend it existed from
951
    # genesis.
952
    # See https://github.com/ethereum/go-ethereum/pull/1588
953
    num_bomb_periods = ((int(block_number) - BOMB_DELAY_BLOCKS) // 100000) - 2
954
    if num_bomb_periods >= 0:
955
        difficulty += 2**num_bomb_periods
956
957
    # Some clients raise the difficulty to `MINIMUM_DIFFICULTY` prior to adding
958
    # the bomb. This bug does not matter because the difficulty is always much
959
    # greater than `MINIMUM_DIFFICULTY` on Mainnet.
960
    return Uint(max(difficulty, int(MINIMUM_DIFFICULTY)))