test_sstore_restoration_sub_frame_revert()

Documentation for tests/amsterdam/eip8037_state_creation_gas_cost_increase/test_state_gas_sstore.py::test_sstore_restoration_sub_frame_revert@87aba1a3.

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_sub_frame_revert --fork Amsterdam

Verify a sub-frame REVERT does not inflate the caller's reservoir under source-based (LIFO) refills.

The sub-call does 0 to x to 0 then REVERTs. The set spilled its state gas from gas_left, so the refill at x to 0 returns it to gas_left, not the reservoir. On REVERT the state gas refills to the parent's gas_left, so the reservoir stays at 0. A probe sized to OOG by 1 then 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_sub_frame_revert(
    state_test: StateTestFiller,
    pre: Alloc,
    fork: Fork,
    call_opcode: Op,
) -> None:
    """
    Verify a sub-frame REVERT does not inflate the caller's reservoir
    under source-based (LIFO) refills.

    The sub-call does 0 to x to 0 then REVERTs. The set spilled its
    state gas from `gas_left`, so the refill at x to 0 returns it to
    `gas_left`, not the reservoir. On REVERT the state gas refills to
    the parent's `gas_left`, so the reservoir stays at 0. A probe sized
    to OOG by 1 then fails, since its fixed forwarded gas cannot reach
    the `gas_left` refund.
    """
    gas_costs = fork.gas_costs()
    # 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
    )

    child_code = Op.SSTORE(0, 1) + Op.SSTORE(0, 0) + Op.REVERT(0, 0)
    child = pre.deploy_contract(code=child_code)
    probe = pre.deploy_contract(code=Op.SSTORE(0, 1))

    # Forward all gas so the child does both SSTOREs and REVERT.
    caller_storage = Storage()
    caller_code = Op.POP(call_opcode(gas=Op.GAS, address=child)) + Op.SSTORE(
        caller_storage.store_next(0, "probe_must_fail"),
        Op.CALL(gas=probe_gas, address=probe),
    )
    caller = pre.deploy_contract(code=caller_code)

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

    post = {caller: Account(storage=caller_storage)}
    state_test(pre=pre, tx=tx, post=post)

Parametrized Test Cases

This test generates 3 parametrized test cases across 1 fork.