test_sstore_restoration_charge_in_ancestor_intermediate_revert()

Documentation for tests/amsterdam/eip8037_state_creation_gas_cost_increase/test_state_gas_sstore.py::test_sstore_restoration_charge_in_ancestor_intermediate_revert@5c024cbb.

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_charge_in_ancestor_intermediate_revert --fork Amsterdam

Verify a deferred refund applied in an intermediate frame still flows back to the caller when that frame REVERTs.

Caller's SSTORE charges; the matching clear in inner is deferred through the chain and lands on middle's own SSTORE-set during incorporate_child_on_success. Middle REVERTs; the applied amount must reach the caller via incorporate_child_on_error. A probe SSTORE sized to OOG by 1 detects loss.

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 in (Op.DELEGATECALL, Op.CALLCODE)
)
@pytest.mark.valid_from("EIP8037")
def test_sstore_restoration_charge_in_ancestor_intermediate_revert(
    state_test: StateTestFiller,
    pre: Alloc,
    fork: Fork,
    call_opcode: Op,
) -> None:
    """
    Verify a deferred refund applied in an intermediate frame still
    flows back to the caller when that frame REVERTs.

    Caller's SSTORE charges; the matching clear in inner is deferred
    through the chain and lands on middle's own SSTORE-set during
    `incorporate_child_on_success`.  Middle REVERTs; the applied
    amount must reach the caller via `incorporate_child_on_error`.
    A probe SSTORE sized to OOG by 1 detects loss.
    """
    gas_costs = fork.gas_costs()
    sstore_state_gas = Op.SSTORE(new_value=1).state_cost(fork)
    intrinsic_cost = fork.transaction_intrinsic_cost_calculator()()
    # Probe SSTORE(0, 1): 2 pushes + cold storage write + state gas - 1,
    # so it OOGs by 1 when the reservoir is 0 and succeeds otherwise.
    probe_gas = (
        2 * gas_costs.VERY_LOW
        + gas_costs.COLD_STORAGE_WRITE
        + sstore_state_gas
        - 1
    )

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

    # Middle's own SSTORE on slot 1 supplies the `state_gas_used`
    # that inner's deferred credit lands on, then middle REVERTs.
    middle_code = (
        Op.SSTORE(1, 1)
        + Op.POP(call_opcode(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()
    caller_code = (
        Op.SSTORE(caller_storage.store_next(1, "caller_set_persists"), 1)
        + Op.POP(call_opcode(gas=Op.GAS, address=middle))
        + Op.SSTORE(
            caller_storage.store_next(1, "probe_must_succeed"),
            Op.CALL(gas=probe_gas, address=probe),
        )
    )
    caller = pre.deploy_contract(code=caller_code)

    # Block state gas commits: caller's slot-0 set + probe's
    # SSTORE-set + caller's outer SSTORE-set on slot 1.  Middle's
    # own slot-1 set is washed by inner's deferred credit before
    # middle reverts, so it does not propagate.  Header gas_used
    # is max(regular, state).
    expected_regular = (
        intrinsic_cost
        + caller_code.regular_cost(fork)
        + middle_code.regular_cost(fork)
        + inner_code.regular_cost(fork)
        + probe_code.regular_cost(fork)
    )
    expected_state = 3 * sstore_state_gas
    expected_gas_used = max(expected_regular, expected_state)

    # Reservoir = 2 * sstore_state_gas covers caller's and middle's
    # sets; the deferred credit refills middle by sstore_state_gas,
    # which flows to the caller on revert.
    tx = Transaction(
        sender=pre.fund_eoa(),
        to=caller,
        state_gas_reservoir=2 * sstore_state_gas,
    )

    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 2 parametrized test cases across 1 fork.