test_sstore_restoration_ancestor_revert()

Documentation for tests/amsterdam/eip8037_state_creation_gas_cost_increase/test_state_gas_sstore.py::test_sstore_restoration_ancestor_revert@2119b382.

Generate fixtures for these test cases for Amsterdam with:

fill -v tests/amsterdam/eip8037_state_creation_gas_cost_increase/test_state_gas_sstore.py::test_sstore_restoration_ancestor_revert --fork Amsterdam

Verify an ancestor REVERT does not inflate the caller's reservoir under source-based (LIFO) refills.

Inner's set spills its state gas from gas_left. The refill at x to 0 returns it to gas_left, and inner's state_gas_spilled propagates to middle on success. Middle then REVERTs, refilling the spilled state gas to the caller's gas_left, not the reservoir. The reservoir stays at 0, so a probe sized to OOG by 1 fails, since its fixed forwarded gas cannot reach the gas_left refund.

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

@pytest.mark.with_all_call_opcodes(
    selector=lambda call_opcode: call_opcode != Op.STATICCALL
)
@pytest.mark.valid_from("EIP8037")
def test_sstore_restoration_ancestor_revert(
    state_test: StateTestFiller,
    pre: Alloc,
    fork: Fork,
    call_opcode: Op,
) -> None:
    """
    Verify an ancestor REVERT does not inflate the caller's reservoir
    under source-based (LIFO) refills.

    Inner's set spills its state gas from `gas_left`. The refill at
    x to 0 returns it to `gas_left`, and inner's
    `state_gas_spilled` propagates to middle on success. Middle
    then REVERTs, refilling the spilled state gas to the caller's
    `gas_left`, not the reservoir. The reservoir stays at 0, so a probe
    sized to OOG by 1 fails, since its fixed forwarded gas cannot reach
    the `gas_left` refund.
    """
    gas_costs = fork.gas_costs()
    intrinsic_cost = fork.transaction_intrinsic_cost_calculator()()
    # Probe SSTORE(0, 1): 2 pushes + cold write + state gas - 1. OOGs by
    # 1 when the reservoir is 0, as forwarded gas misses gas_left.
    probe_gas = (
        2 * gas_costs.VERY_LOW
        + gas_costs.COLD_STORAGE_WRITE
        + Op.SSTORE(new_value=1).state_cost(fork)
        - 1
    )

    set_op = Op.SSTORE.with_metadata(
        key_warm=False,
        original_value=0,
        current_value=0,
        new_value=1,
    )(0, 1)
    clear_op = Op.SSTORE.with_metadata(
        key_warm=True,
        original_value=0,
        current_value=1,
        new_value=0,
    )(0, 0)
    inner_code = set_op + clear_op + Op.STOP
    inner = pre.deploy_contract(code=inner_code)

    middle_code = Op.POP(Op.CALL(gas=Op.GAS, address=inner)) + Op.REVERT(0, 0)
    middle = pre.deploy_contract(code=middle_code)

    probe_code = Op.SSTORE(0, 1)
    probe = pre.deploy_contract(code=probe_code)

    caller_storage = Storage()
    # The probe OOGs and returns 0, so the caller's outer SSTORE is a
    # cold no-op (0 to 0) on a fresh slot, charging only
    # COLD_STORAGE_ACCESS rather than the cold set `regular_cost`
    # assumes by default.
    caller_code = Op.POP(
        call_opcode(gas=Op.GAS, address=middle)
    ) + Op.SSTORE.with_metadata(
        key_warm=False,
        original_value=0,
        current_value=0,
        new_value=0,
    )(
        caller_storage.store_next(0, "probe_must_fail"),
        Op.CALL(gas=probe_gas, address=probe),
    )
    caller = pre.deploy_contract(code=caller_code)

    # No SSTORE-set persists (inner's set+clear cancel, middle reverts,
    # the probe OOGs and reverts, and the caller's outer SSTORE is a
    # no-op), so block state gas is zero and header gas_used (the max of
    # regular and state) is just the regular total. The probe burns its
    # full forwarded budget on the OOG; its CALL's cold-access surcharge
    # is already counted in the caller's regular cost.
    expected_gas_used = (
        intrinsic_cost
        + caller_code.regular_cost(fork)
        + middle_code.regular_cost(fork)
        + inner_code.regular_cost(fork)
        + probe_gas
    )

    # gas_limit at the cap means the caller's reservoir starts at 0.
    tx = Transaction(
        sender=pre.fund_eoa(),
        to=caller,
        state_gas_reservoir=0,
    )

    state_test(
        pre=pre,
        tx=tx,
        post={caller: Account(storage=caller_storage)},
        blockchain_test_header_verify=Header(gas_used=expected_gas_used),
    )

Parametrized Test Cases

This test generates 3 parametrized test cases across 1 fork.