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

74
BLOCK_REWARD = U256(2 * 10**18)

BASE_FEE_MAX_CHANGE_DENOMINATOR

70
BASE_FEE_MAX_CHANGE_DENOMINATOR = Uint(8)

ELASTICITY_MULTIPLIER

71
ELASTICITY_MULTIPLIER = Uint(2)

MINIMUM_DIFFICULTY

77
MINIMUM_DIFFICULTY = Uint(131072)

MAX_OMMER_DEPTH

78
MAX_OMMER_DEPTH = Uint(6)

BOMB_DELAY_BLOCKS

79
BOMB_DELAY_BLOCKS = 11400000

EMPTY_OMMER_HASH

72
EMPTY_OMMER_HASH = keccak256(rlp.encode([]))

BlockChain

History and current state of the block chain.

75
@dataclass
class BlockChain:

blocks

81
    blocks: List[Block]

state

82
    state: State

chain_id

83
    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:
87
    <snip>
106
    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]:
110
    <snip>
130
    recent_blocks = chain.blocks[-255:]
131
    # TODO: This function has not been tested rigorously
132
    if len(recent_blocks) == 0:
133
        return []
134
135
    recent_block_hashes = []
136
137
    for block in recent_blocks:
138
        prev_block_hash = block.header.parent_hash
139
        recent_block_hashes.append(prev_block_hash)
140
141
    # We are computing the hash only for the most recent block and not for
142
    # the rest of the blocks as they have successors which have the hash of
143
    # the current block as parent hash.
144
    most_recent_block_hash = keccak256(rlp.encode(recent_blocks[-1].header))
145
    recent_block_hashes.append(most_recent_block_hash)
146
147
    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:
151
    <snip>
173
    validate_header(chain, block.header)
182
    validate_ommers(block.ommers, block.header, chain)
174
    if block.ommers != ():
175
        raise InvalidBlock
176
177
    block_state = BlockState(pre_state=chain.state)
178
179
    block_env = vm.BlockEnvironment(
180
        chain_id=chain.chain_id,
181
        state=block_state,
182
        block_gas_limit=block.header.gas_limit,
183
        block_hashes=get_last_256_block_hashes(chain),
184
        coinbase=block.header.coinbase,
185
        number=block.header.number,
186
        base_fee_per_gas=block.header.base_fee_per_gas,
187
        time=block.header.timestamp,
195
        difficulty=block.header.difficulty,
188
        prev_randao=block.header.prev_randao,
189
    )
190
191
    block_output = apply_body(
192
        block_env=block_env,
193
        transactions=block.transactions,
201
        ommers=block.ommers,
194
    )
195
    block_diff = extract_block_diff(block_state)
196
    block_state_root, _ = chain.state.compute_state_root_and_trie_changes(
197
        block_diff.account_changes,
198
        block_diff.storage_changes,
199
        block_diff.storage_clears,
200
    )
201
    transactions_root = root(block_output.transactions_trie)
202
    receipt_root = root(block_output.receipts_trie)
203
    block_logs_bloom = logs_bloom(block_output.block_logs)
204
205
    if block_output.block_gas_used != block.header.gas_used:
206
        raise InvalidBlock(
207
            f"{block_output.block_gas_used} != {block.header.gas_used}"
208
        )
209
    if transactions_root != block.header.transactions_root:
210
        raise InvalidBlock
211
    if block_state_root != block.header.state_root:
212
        raise InvalidBlock
213
    if receipt_root != block.header.receipt_root:
214
        raise InvalidBlock
215
    if block_logs_bloom != block.header.bloom:
216
        raise InvalidBlock
217
218
    apply_changes_to_state(chain.state, block_diff)
219
    chain.blocks.append(block)
220
    if len(chain.blocks) > 255:
221
        # Real clients have to store more blocks to deal with reorgs, but the
222
        # protocol only requires the last 255
223
        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:
232
    <snip>
252
    parent_gas_target = parent_gas_limit // ELASTICITY_MULTIPLIER
253
    if not check_gas_limit(block_gas_limit, parent_gas_limit):
254
        raise InvalidBlock
255
256
    if parent_gas_used == parent_gas_target:
257
        expected_base_fee_per_gas = parent_base_fee_per_gas
258
    elif parent_gas_used > parent_gas_target:
259
        gas_used_delta = parent_gas_used - parent_gas_target
260
261
        parent_fee_gas_delta = parent_base_fee_per_gas * gas_used_delta
262
        target_fee_gas_delta = parent_fee_gas_delta // parent_gas_target
263
264
        base_fee_per_gas_delta = max(
265
            target_fee_gas_delta // BASE_FEE_MAX_CHANGE_DENOMINATOR,
266
            Uint(1),
267
        )
268
269
        expected_base_fee_per_gas = (
270
            parent_base_fee_per_gas + base_fee_per_gas_delta
271
        )
272
    else:
273
        gas_used_delta = parent_gas_target - parent_gas_used
274
275
        parent_fee_gas_delta = parent_base_fee_per_gas * gas_used_delta
276
        target_fee_gas_delta = parent_fee_gas_delta // parent_gas_target
277
278
        base_fee_per_gas_delta = (
279
            target_fee_gas_delta // BASE_FEE_MAX_CHANGE_DENOMINATOR
280
        )
281
282
        expected_base_fee_per_gas = (
283
            parent_base_fee_per_gas - base_fee_per_gas_delta
284
        )
285
286
    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:
290
    <snip>
308
    if header.number < Uint(1):
309
        raise InvalidBlock
318
    parent_header_number = header.number - Uint(1)
319
    first_block_number = chain.blocks[0].header.number
320
    last_block_number = chain.blocks[-1].header.number
310
322
    if (
323
        parent_header_number < first_block_number
324
        or parent_header_number > last_block_number
325
    ):
326
        raise InvalidBlock
327
328
    parent_header = chain.blocks[
329
        parent_header_number - first_block_number
330
    ].header
311
    parent_header = chain.blocks[-1].header
312
313
    if header.gas_used > header.gas_limit:
314
        raise InvalidBlock
315
316
    expected_base_fee_per_gas = calculate_base_fee_per_gas(
317
        header.gas_limit,
318
        parent_header.gas_limit,
319
        parent_header.gas_used,
320
        parent_header.base_fee_per_gas,
321
    )
322
    if expected_base_fee_per_gas != header.base_fee_per_gas:
323
        raise InvalidBlock
343
344
    parent_has_ommers = parent_header.ommers_hash != EMPTY_OMMER_HASH
324
    if header.timestamp <= parent_header.timestamp:
325
        raise InvalidBlock
326
    if header.number != parent_header.number + Uint(1):
327
        raise InvalidBlock
328
    if len(header.extra_data) > 32:
329
        raise InvalidBlock
351
352
    block_difficulty = calculate_block_difficulty(
353
        header.number,
354
        header.timestamp,
355
        parent_header.timestamp,
356
        parent_header.difficulty,
357
        parent_has_ommers,
358
    )
359
    if header.difficulty != block_difficulty:
330
    if header.difficulty != 0:
331
        raise InvalidBlock
332
    if header.nonce != b"\x00\x00\x00\x00\x00\x00\x00\x00":
333
        raise InvalidBlock
334
    if header.ommers_hash != EMPTY_OMMER_HASH:
335
        raise InvalidBlock
336
337
    block_parent_hash = keccak256(rlp.encode(parent_header))
338
    if header.parent_hash != block_parent_hash:
364
        raise InvalidBlock
365
366
    validate_proof_of_work(header)
339
        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:
370
    <snip>
393
    header_data_without_pow_artefacts = (
394
        header.parent_hash,
395
        header.ommers_hash,
396
        header.coinbase,
397
        header.state_root,
398
        header.transactions_root,
399
        header.receipt_root,
400
        header.bloom,
401
        header.difficulty,
402
        header.number,
403
        header.gas_limit,
404
        header.gas_used,
405
        header.timestamp,
406
        header.extra_data,
407
        header.base_fee_per_gas,
408
    )
409
410
    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:
414
    <snip>
429
    header_hash = generate_header_hash_for_pow(header)
430
    # TODO: Memoize this somewhere and read from that data instead of
431
    # calculating cache for every block validation.
432
    cache = generate_cache(header.number)
433
    mix_digest, result = hashimoto_light(
434
        header_hash, header.nonce, cache, dataset_size(header.number)
435
    )
436
    if mix_digest != header.mix_digest:
437
        raise InvalidBlock
438
439
    limit = Uint(U256.MAX_VALUE) + Uint(1)
440
    if Uint.from_be_bytes(result) > (limit // header.difficulty):
441
        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. PriorityFeeGreaterThanMaxFeeError:PriorityFeeGreaterThanMaxFeeError : If the priority fee is greater than the maximum fee per gas. 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]:
348
    <snip>
387
    gas_available = block_env.block_gas_limit - block_output.block_gas_used
388
    if tx.gas > gas_available:
389
        raise GasUsedExceedsLimitError("gas used exceeds limit")
390
    sender_address = recover_sender(block_env.chain_id, tx)
391
    sender_account = get_account(tx_state, sender_address)
392
393
    if isinstance(tx, FeeMarketTransaction):
394
        if tx.max_fee_per_gas < tx.max_priority_fee_per_gas:
395
            raise PriorityFeeGreaterThanMaxFeeError(
396
                "priority fee greater than max fee"
397
            )
398
        if tx.max_fee_per_gas < block_env.base_fee_per_gas:
399
            raise InsufficientMaxFeePerGasError(
400
                tx.max_fee_per_gas, block_env.base_fee_per_gas
401
            )
402
403
        priority_fee_per_gas = min(
404
            tx.max_priority_fee_per_gas,
405
            tx.max_fee_per_gas - block_env.base_fee_per_gas,
406
        )
407
        effective_gas_price = priority_fee_per_gas + block_env.base_fee_per_gas
408
        max_gas_fee = tx.gas * tx.max_fee_per_gas
409
    else:
410
        if tx.gas_price < block_env.base_fee_per_gas:
411
            raise InvalidBlock
412
        effective_gas_price = tx.gas_price
413
        max_gas_fee = tx.gas * tx.gas_price
414
415
    if sender_account.nonce > Uint(tx.nonce):
416
        raise NonceMismatchError("nonce too low")
417
    elif sender_account.nonce < Uint(tx.nonce):
418
        raise NonceMismatchError("nonce too high")
419
    if Uint(sender_account.balance) < max_gas_fee + Uint(tx.value):
420
        raise InsufficientBalanceError("insufficient sender balance")
421
    if sender_account.code_hash != EMPTY_CODE_HASH:
422
        raise InvalidSenderError("not EOA")
423
424
    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:
433
    <snip>
454
    receipt = Receipt(
455
        succeeded=error is None,
456
        cumulative_gas_used=cumulative_gas_used,
457
        bloom=logs_bloom(logs),
458
        logs=logs,
459
    )
460
461
    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:
468
    <snip>
491
    block_output = vm.BlockOutput()
492
493
    for i, tx in enumerate(map(decode_transaction, transactions)):
494
        process_transaction(block_env, block_output, tx, Uint(i))
495
602
    pay_rewards(block_env, ommers)
603
496
    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:
610
    <snip>
632
    block_hash = keccak256(rlp.encode(block_header))
633
    if keccak256(rlp.encode(ommers)) != block_header.ommers_hash:
634
        raise InvalidBlock
635
636
    if len(ommers) == 0:
637
        # Nothing to validate
638
        return
639
640
    # Check that each ommer satisfies the constraints of a header
641
    for ommer in ommers:
642
        if Uint(1) > ommer.number or ommer.number >= block_header.number:
643
            raise InvalidBlock
644
        validate_header(chain, ommer)
645
    if len(ommers) > 2:
646
        raise InvalidBlock
647
648
    ommers_hashes = [keccak256(rlp.encode(ommer)) for ommer in ommers]
649
    if len(ommers_hashes) != len(set(ommers_hashes)):
650
        raise InvalidBlock
651
652
    recent_canonical_blocks = chain.blocks[-(MAX_OMMER_DEPTH + Uint(1)) :]
653
    recent_canonical_block_hashes = {
654
        keccak256(rlp.encode(block.header))
655
        for block in recent_canonical_blocks
656
    }
657
    recent_ommers_hashes: Set[Hash32] = set()
658
    for block in recent_canonical_blocks:
659
        recent_ommers_hashes = recent_ommers_hashes.union(
660
            {keccak256(rlp.encode(ommer)) for ommer in block.ommers}
661
        )
662
663
    for ommer_index, ommer in enumerate(ommers):
664
        ommer_hash = ommers_hashes[ommer_index]
665
        if ommer_hash == block_hash:
666
            raise InvalidBlock
667
        if ommer_hash in recent_canonical_block_hashes:
668
            raise InvalidBlock
669
        if ommer_hash in recent_ommers_hashes:
670
            raise InvalidBlock
671
672
        # Ommer age with respect to the current block. For example, an age of
673
        # 1 indicates that the ommer is a sibling of previous block.
674
        ommer_age = block_header.number - ommer.number
675
        if Uint(1) > ommer_age or ommer_age > MAX_OMMER_DEPTH:
676
            raise InvalidBlock
677
        if ommer.parent_hash not in recent_canonical_block_hashes:
678
            raise InvalidBlock
679
        if ommer.parent_hash == block_header.parent_hash:
680
            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:
687
    <snip>
709
    rewards_state = TransactionState(parent=block_env.state)
710
    ommer_count = U256(len(ommers))
711
    miner_reward = BLOCK_REWARD + (ommer_count * (BLOCK_REWARD // U256(32)))
712
    create_ether(rewards_state, block_env.coinbase, miner_reward)
713
714
    for ommer in ommers:
715
        # Ommer age with respect to the current block.
716
        ommer_age = U256(block_env.number - ommer.number)
717
        ommer_miner_reward = ((U256(8) - ommer_age) * BLOCK_REWARD) // U256(8)
718
        create_ether(rewards_state, ommer.coinbase, ommer_miner_reward)
719
720
    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:
505
    <snip>
529
    tx_state = TransactionState(parent=block_env.state)
530
531
    trie_set(
532
        block_output.transactions_trie,
533
        rlp.encode(index),
534
        encode_transaction(tx),
535
    )
536
537
    intrinsic_gas = validate_transaction(tx)
538
539
    (
540
        sender,
541
        effective_gas_price,
542
    ) = check_transaction(
543
        block_env=block_env,
544
        block_output=block_output,
545
        tx=tx,
546
        tx_state=tx_state,
547
    )
548
549
    sender_account = get_account(tx_state, sender)
550
551
    effective_gas_fee = tx.gas * effective_gas_price
552
553
    gas = tx.gas - intrinsic_gas
554
    increment_nonce(tx_state, sender)
555
556
    sender_balance_after_gas_fee = (
557
        Uint(sender_account.balance) - effective_gas_fee
558
    )
559
    set_account_balance(tx_state, sender, U256(sender_balance_after_gas_fee))
560
561
    access_list_addresses = set()
562
    access_list_storage_keys = set()
563
    if isinstance(tx, (AccessListTransaction, FeeMarketTransaction)):
564
        for access in tx.access_list:
565
            access_list_addresses.add(access.account)
566
            for slot in access.slots:
567
                access_list_storage_keys.add((access.account, slot))
568
569
    tx_env = vm.TransactionEnvironment(
570
        origin=sender,
571
        gas_price=effective_gas_price,
572
        gas=gas,
573
        access_list_addresses=access_list_addresses,
574
        access_list_storage_keys=access_list_storage_keys,
575
        state=tx_state,
576
        index_in_block=index,
577
        tx_hash=get_transaction_hash(encode_transaction(tx)),
578
    )
579
580
    message = prepare_message(block_env, tx_env, tx)
581
582
    tx_output = process_message_call(message)
583
584
    tx_gas_used_before_refund = tx.gas - tx_output.gas_left
585
    tx_gas_refund = min(
586
        tx_gas_used_before_refund // Uint(5), Uint(tx_output.refund_counter)
587
    )
588
    tx_gas_used_after_refund = tx_gas_used_before_refund - tx_gas_refund
589
    tx_gas_left = tx.gas - tx_gas_used_after_refund
590
    gas_refund_amount = tx_gas_left * effective_gas_price
591
592
    # For non-1559 transactions effective_gas_price == tx.gas_price
593
    priority_fee_per_gas = effective_gas_price - block_env.base_fee_per_gas
594
    transaction_fee = tx_gas_used_after_refund * priority_fee_per_gas
595
596
    # refund gas
597
    sender_balance_after_refund = get_account(tx_state, sender).balance + U256(
598
        gas_refund_amount
599
    )
600
    set_account_balance(tx_state, sender, sender_balance_after_refund)
601
602
    # transfer miner fees
603
    coinbase_balance_after_mining_fee = get_account(
604
        tx_state, block_env.coinbase
605
    ).balance + U256(transaction_fee)
830
    if coinbase_balance_after_mining_fee != 0:
831
        set_account_balance(
832
            tx_state,
833
            block_env.coinbase,
834
            coinbase_balance_after_mining_fee,
835
        )
836
    elif account_exists_and_is_empty(tx_state, block_env.coinbase):
837
        destroy_account(tx_state, block_env.coinbase)
606
    set_account_balance(
607
        tx_state, block_env.coinbase, coinbase_balance_after_mining_fee
608
    )
609
610
    for address in tx_output.accounts_to_delete:
611
        destroy_account(tx_state, address)
841
842
    destroy_touched_empty_accounts(tx_state, tx_output.touched_accounts)
612
613
    block_output.block_gas_used += tx_gas_used_after_refund
614
615
    receipt = make_receipt(
616
        tx, tx_output.error, block_output.block_gas_used, tx_output.logs
617
    )
618
619
    receipt_key = rlp.encode(Uint(index))
620
    block_output.receipt_keys += (receipt_key,)
621
622
    trie_set(
623
        block_output.receipts_trie,
624
        receipt_key,
625
        receipt,
626
    )
627
628
    block_output.block_logs += tx_output.logs
629
630
    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:
634
    <snip>
662
    max_adjustment_delta = parent_gas_limit // GasCosts.LIMIT_ADJUSTMENT_FACTOR
663
    if gas_limit >= parent_gas_limit + max_adjustment_delta:
664
        return False
665
    if gas_limit <= parent_gas_limit - max_adjustment_delta:
666
        return False
667
    if gas_limit < GasCosts.LIMIT_MINIMUM:
668
        return False
669
670
    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:
911
    <snip>
950
    offset = (
951
        int(parent_difficulty)
952
        // 2048
953
        * max(
954
            (2 if parent_has_ommers else 1)
955
            - int(block_timestamp - parent_timestamp) // 9,
956
            -99,
957
        )
958
    )
959
    difficulty = int(parent_difficulty) + offset
960
    # Historical Note: The difficulty bomb was not present in Ethereum at the
961
    # start of Frontier, but was added shortly after launch. However since the
962
    # bomb has no effect prior to block 200000 we pretend it existed from
963
    # genesis.
964
    # See https://github.com/ethereum/go-ethereum/pull/1588
965
    num_bomb_periods = ((int(block_number) - BOMB_DELAY_BLOCKS) // 100000) - 2
966
    if num_bomb_periods >= 0:
967
        difficulty += 2**num_bomb_periods
968
969
    # Some clients raise the difficulty to `MINIMUM_DIFFICULTY` prior to adding
970
    # the bomb. This bug does not matter because the difficulty is always much
971
    # greater than `MINIMUM_DIFFICULTY` on Mainnet.
972
    return Uint(max(difficulty, int(MINIMUM_DIFFICULTY)))