test_extra_tx_admission_uses_pre_refund_gas()

Documentation for tests/amsterdam/eip7778_block_gas_accounting_without_refunds/test_gas_accounting.py::test_extra_tx_admission_uses_pre_refund_gas@26332146.

Generate fixtures for these test cases for Amsterdam with:

fill -v tests/amsterdam/eip7778_block_gas_accounting_without_refunds/test_gas_accounting.py::test_extra_tx_admission_uses_pre_refund_gas --fork Amsterdam

Test that the admission gate uses the pre-refund accumulator when the trailing tx's gas_limit exceeds its actual usage.

Without this slack a post-refund gate is masked: the block is still rejected by the gas_used > gas_limit check. With it, a buggy implementation admits the extra tx yet stays within the block gas limit, diverging from the expected-invalid fixture.

Source code in tests/amsterdam/eip7778_block_gas_accounting_without_refunds/test_gas_accounting.py

@pytest.mark.inclusion_test
@pytest.mark.parametrize(
    "refund_tx_reverts",
    [
        pytest.param(True, id="refund_tx_reverts"),
        pytest.param(False, id=""),
    ],
)
@pytest.mark.with_all_refund_types()
@pytest.mark.filter_combinations(
    lambda refund_type, refund_tx_reverts, **_: not (
        refund_type == RefundTypes.STORAGE_CLEAR and refund_tx_reverts
    ),
    reason=(
        "STORAGE_CLEAR refund is zero on revert, so post_refund == "
        "pre_refund and the admission bypass cannot manifest"
    ),
)
@pytest.mark.exception_test
@pytest.mark.execute(pytest.mark.skip(reason="Requires specific gas price"))
@pytest.mark.valid_from("EIP7778")
def test_extra_tx_admission_uses_pre_refund_gas(
    blockchain_test: BlockchainTestFiller,
    pre: Alloc,
    fork: Fork,
    refund_type: RefundTypes,
    refund_tx_reverts: bool,
) -> None:
    """
    Test that the admission gate uses the pre-refund accumulator when
    the trailing tx's gas_limit exceeds its actual usage.

    Without this slack a post-refund gate is masked: the block is
    still rejected by the gas_used > gas_limit check. With it, a buggy
    implementation admits the extra tx yet stays within the block gas
    limit, diverging from the expected-invalid fixture.
    """
    intrinsic_cost_calc = fork.transaction_intrinsic_cost_calculator()

    refunds_count = 10
    stop_address = pre.deterministic_deploy_contract(deploy_code=Op.STOP)

    post = Alloc()
    (
        gas_used_post_refund,
        gas_used_pre_refund,
        _,
        call_data_floor_cost,
        refund_tx,
    ) = build_refund_tx(
        fork=fork,
        pre=pre,
        post=post,
        refund_types={refund_type},
        refunds_count=refunds_count,
        refund_tx_reverts=refund_tx_reverts,
        exceed_block_gas_limit=True,
    )

    assert gas_used_pre_refund > gas_used_post_refund, (
        "Parametrization must produce a refund; without one the admission "
        "bypass cannot occur"
    )

    refund_tx_block_gas_used = max(gas_used_pre_refund, call_data_floor_cost)

    extra_tx_sender = pre.fund_eoa()
    extra_tx_intrinsic = intrinsic_cost_calc(calldata=b"")

    # Slack so a buggy admit stays within the block gas limit.
    extra_tx_gas_limit = 2 * extra_tx_intrinsic
    extra_tx = Transaction(
        to=stop_address,
        gas_limit=extra_tx_gas_limit,
        sender=extra_tx_sender,
        error=TransactionException.GAS_ALLOWANCE_EXCEEDED,
    )

    environment_gas_limit = refund_tx_block_gas_used + extra_tx_gas_limit - 1

    blockchain_test(
        pre=pre,
        blocks=[
            Block(
                txs=[refund_tx, extra_tx],
                exception=[
                    BlockException.GAS_USED_OVERFLOW,
                    TransactionException.GAS_ALLOWANCE_EXCEEDED,
                ],
                gas_limit=environment_gas_limit,
            )
        ],
        post=post,
        genesis_environment=Environment(gas_limit=environment_gas_limit),
    )

Parametrized Test Cases

This test generates 1 parametrized test case across 1 fork.