test_nested_calls_reservoir_passing()

Documentation for tests/amsterdam/eip8037_state_creation_gas_cost_increase/test_state_gas_call.py::test_nested_calls_reservoir_passing@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_nested_calls_reservoir_passing --fork Amsterdam

Test reservoir passes through nested calls.

The reservoir is passed from A to B to C. C performs an SSTORE using the reservoir gas. After all calls return, A verifies success. C is handed only its execution cost, so one gas less halts it before the SSTORE and leaves the reservoir untouched.

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

@pytest.mark.parametrize(
    "sufficient_gas",
    [
        pytest.param(False, id="insufficient_gas"),
        pytest.param(True, id="sufficient_gas"),
    ],
)
@pytest.mark.valid_from("EIP8037")
def test_nested_calls_reservoir_passing(
    state_test: StateTestFiller,
    pre: Alloc,
    fork: Fork,
    sufficient_gas: bool,
) -> None:
    """
    Test reservoir passes through nested calls.

    The reservoir is passed from A to B to C. C performs an SSTORE
    using the reservoir gas. After all calls return, A verifies
    success. C is handed only its execution cost, so one gas less
    halts it before the SSTORE and leaves the reservoir untouched.
    """
    sstore_state_gas = Op.SSTORE(new_value=1).state_cost(fork)

    c_storage = Storage()
    c_code = Op.SSTORE(c_storage.store_next(1 if sufficient_gas else 0), 1)
    c = pre.deploy_contract(code=c_code)
    c_gas = c_code.execution_cost(fork)
    if not sufficient_gas:
        c_gas -= 1

    # Each hop forwards only execution gas; the reservoir rides along in
    # full, so C's SSTORE lands only if it reached the bottom frame. B
    # gets 64/63 of C's need because a frame may forward at most 63/64
    # of the gas it holds.
    b_code = Op.CALL(gas=c_gas, address=c)
    b = pre.deploy_contract(code=b_code)

    a_storage = Storage()
    call_slot = a_storage.store_next(1, "nested_call_succeeds")
    a_code = Op.SSTORE(
        call_slot,
        Op.CALL(address=b),
        # gas accounting
        original_value=1,
        current_value=1,
        new_value=1,
        key_warm=False,
    )
    a = pre.deploy_contract(code=a_code, storage={call_slot: 1})

    execution_gas = (
        fork.transaction_intrinsic_cost_calculator()()
        + a_code.execution_cost(fork)
        + b_code.execution_cost(fork)
        + c_gas
    )
    expected_gas_used = max(
        execution_gas, sstore_state_gas if sufficient_gas else 0
    )

    tx = Transaction(
        to=a,
        state_gas_reservoir=sstore_state_gas,
        sender=pre.fund_eoa(),
    )

    post = {
        a: Account(storage=a_storage),
        c: Account(storage=c_storage),
    }
    state_test(
        pre=pre,
        post=post,
        tx=tx,
        blockchain_test_header_verify=Header(gas_used=expected_gas_used),
    )

Parametrized Test Cases

This test generates 2 parametrized test cases across 1 fork.