test_call_frame_credit_repays_spill_before_fixed_gas_probe()

Documentation for tests/amsterdam/eip8037_state_creation_gas_cost_increase/test_state_gas_cross_frame_refund.py::test_call_frame_credit_repays_spill_before_fixed_gas_probe@622620d8.

Generate fixtures for these test cases for Amsterdam with:

fill -v tests/amsterdam/eip8037_state_creation_gas_cost_increase/test_state_gas_cross_frame_refund.py::test_call_frame_credit_repays_spill_before_fixed_gas_probe --fork Amsterdam

Test a plain CALL credit repays the spill before a fixed-gas probe.

The transaction starts with no reservoir. The spilling frame merges its claim into the parent. A sibling or grandchild clears the slot, and its credit repays that claim when it reaches the parent. The probe receives only its execution cost, so it cannot fund its state charge from the repaid gas. It fails with or without the clear.

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

@pytest.mark.parametrize(
    "raises_credit",
    [
        pytest.param(True, id="credit_repaid_probe_oogs"),
        pytest.param(False, id="no_credit_probe_oogs"),
    ],
)
@pytest.mark.parametrize("depth", ["sibling", "grandchild"])
@pytest.mark.valid_from("EIP8037")
def test_call_frame_credit_repays_spill_before_fixed_gas_probe(
    state_test: StateTestFiller,
    pre: Alloc,
    fork: Fork,
    depth: str,
    raises_credit: bool,
) -> None:
    """
    Test a plain CALL credit repays the spill before a fixed-gas probe.

    The transaction starts with no reservoir. The spilling frame merges
    its claim into the parent. A sibling or grandchild clears the slot,
    and its credit repays that claim when it reaches the parent. The
    probe receives only its execution cost, so it cannot fund its state
    charge from the repaid gas. It fails with or without the clear.
    """
    # A CALL callee owns its storage, so splitting the charge from the
    # credit needs one contract entered twice rather than two contracts.
    toggler = pre.deploy_contract(
        code=Op.SSTORE(SLOT_X, Op.ISZERO(Op.SLOAD(SLOT_X)))
    )
    clearing_target = toggler
    if depth == "grandchild":
        clearing_target = pre.deploy_contract(
            code=Op.POP(Op.CALL(gas=Op.GAS, address=toggler))
        )

    # Without the second entry no credit is raised. Both cases leave
    # the reservoir empty when the fixed-gas probe runs.
    if not raises_credit:
        clearing_target = pre.deploy_contract(code=Op.STOP)

    probe_storage = Storage()
    probe_code = Op.SSTORE(probe_storage.store_next(0, "probe_ran"), 1)
    probe = pre.deploy_contract(probe_code)
    probe_stipend = probe_code.execution_cost(fork)

    entry = pre.deploy_contract(
        code=(
            Op.POP(Op.CALL(gas=Op.GAS, address=toggler))
            + Op.POP(Op.CALL(gas=Op.GAS, address=clearing_target))
            + Op.POP(Op.CALL(gas=probe_stipend, address=probe))
        )
    )

    tx = Transaction(
        to=entry,
        state_gas_reservoir=0,
        sender=pre.fund_eoa(),
    )

    post = {
        toggler: Account(storage={SLOT_X: 0 if raises_credit else 1}),
        probe: Account(storage=probe_storage),
    }
    state_test(pre=pre, post=post, tx=tx)

Parametrized Test Cases

This test generates 4 parametrized test cases across 1 fork.