test_child_failure_refunds_state_gas_to_reservoir_not_gas_left()

Documentation for tests/amsterdam/eip8037_state_creation_gas_cost_increase/test_state_gas_call.py::test_child_failure_refunds_state_gas_to_reservoir_not_gas_left@622620d8.

Generate fixtures for these test cases for Amsterdam with:

fill -v tests/amsterdam/eip8037_state_creation_gas_cost_increase/test_state_gas_call.py::test_child_failure_refunds_state_gas_to_reservoir_not_gas_left --fork Amsterdam

Verify state gas from a failing child is restored to the reservoir, so a sibling probe SSTORE can draw from it under a tight execution stipend. Covers SSTORE and CALL-value (new account) state-gas charge paths.

Source code in tests/amsterdam/eip8037_state_creation_gas_cost_increase/test_state_gas_call.py

@pytest.mark.parametrize(
    "call_opcode,charge_via",
    [
        pytest.param(Op.CALL, "sstore", id="call_sstore_charge"),
        pytest.param(
            Op.DELEGATECALL, "sstore", id="delegatecall_sstore_charge"
        ),
        pytest.param(
            Op.CALL,
            "call_value_new_account",
            id="call_call_value_new_account_charge",
        ),
        pytest.param(
            Op.DELEGATECALL,
            "call_value_new_account",
            id="delegatecall_call_value_new_account_charge",
        ),
    ],
)
@pytest.mark.valid_from("EIP8037")
def test_child_failure_refunds_state_gas_to_reservoir_not_gas_left(
    state_test: StateTestFiller,
    pre: Alloc,
    fork: Fork,
    call_opcode: Op,
    charge_via: str,
) -> None:
    """
    Verify state gas from a failing child is restored to the
    reservoir, so a sibling probe SSTORE can draw from it under a
    tight execution stipend. Covers SSTORE and CALL-value (new
    account) state-gas charge paths.
    """
    sstore_state_gas = Op.SSTORE(new_value=1).state_cost(fork)

    probe_storage = Storage()
    probe_code = Op.SSTORE(probe_storage.store_next(1, "probe_ran"), 1)

    if charge_via == "sstore":
        child_code: Bytecode = Op.SSTORE(0, 1) + Op.REVERT(0, 0)
        child_balance = 0
    else:
        fresh_target = pre.fund_eoa(amount=0)
        child_code = Op.POP(
            Op.CALL(
                gas=Op.GAS,
                address=fresh_target,
                value=1,
                value_transfer=True,
                account_new=True,
            )
        ) + Op.REVERT(0, 0)
        child_balance = 1
    child_state_charge = child_code.state_cost(fork)

    delegated = call_opcode == Op.DELEGATECALL
    child = pre.deploy_contract(
        code=child_code, balance=0 if delegated else child_balance
    )
    probe = pre.deploy_contract(probe_code)
    probe_stipend = probe_code.execution_cost(fork)

    parent = pre.deploy_contract(
        code=(
            Op.POP(call_opcode(gas=Op.GAS, address=child))
            + Op.POP(call_opcode(gas=probe_stipend, address=probe))
        ),
        balance=child_balance if delegated else 0,
    )

    # Reservoir must cover the child's state charge (refunded on
    # REVERT) so the probe SSTORE can draw from it afterwards.
    reservoir = max(child_state_charge, sstore_state_gas)

    tx = Transaction(
        to=parent,
        state_gas_reservoir=reservoir,
        sender=pre.fund_eoa(),
    )

    # DELEGATECALL executes the callee in the caller's storage
    # context, so the probe's SSTORE lands on `parent` instead of
    # `probe`.
    if delegated:
        post: dict = {parent: Account(storage=probe_storage)}
    else:
        post = {probe: Account(storage=probe_storage)}

    state_test(
        pre=pre,
        post=post,
        tx=tx,
        blockchain_test_header_verify=Header(gas_used=sstore_state_gas),
    )

Parametrized Test Cases

This test generates 4 parametrized test cases across 1 fork.