test_cross_frame_refund_repays_spill_at_a_create()

Documentation for tests/amsterdam/eip8037_state_creation_gas_cost_increase/test_state_gas_cross_frame_refund.py::test_cross_frame_refund_repays_spill_at_a_create@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_cross_frame_refund_repays_spill_at_a_create --fork Amsterdam

Test a create merging a refund repays the spill.

The initcode reaches a holder contract that clears its own slot. The refund repays the spill at the create merge and the next window's account creation spills afresh, so the clearing window costs one slot's state gas less than the no-op window.

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

@pytest.mark.with_all_create_opcodes
@pytest.mark.valid_from("EIP8037")
def test_cross_frame_refund_repays_spill_at_a_create(
    state_test: StateTestFiller,
    pre: Alloc,
    fork: Fork,
    create_opcode: Opcode,
) -> None:
    """
    Test a create merging a refund repays the spill.

    The initcode reaches a holder contract that clears its own slot.
    The refund repays the spill at the create merge and the next
    window's account creation spills afresh, so the clearing window
    costs one slot's state gas less than the no-op window.
    """
    holder = deploy_slot_holder(pre)
    set_slot = Op.POP(Op.CALL(address=holder, args_size=1))
    # Pushing the zero arguments with PUSH0 keeps the initcode inside a
    # single memory word.
    initcode = Op.CALL(
        Op.GAS, holder, Op.PUSH0, Op.PUSH0, Op.PUSH0, Op.PUSH0, Op.PUSH0
    )
    mstore_value, size = init_code_at_high_bytes(initcode)

    # The probe measures with memory below 96, so the initcode sits
    # above it.
    code_offset = 96

    def window(salt: int) -> Bytecode:
        # A repeated CREATE2 salt would collide with the account the
        # previous window created.
        if create_opcode == Op.CREATE2:
            return Op.POP(Op.CREATE2(0, code_offset, size, salt))
        return Op.POP(Op.CREATE(0, code_offset, size))

    contract = pre.deploy_contract(
        code=Op.MSTORE(code_offset, mstore_value)
        + clearing_probe_code(set_slot, [window(salt) for salt in range(3)])
    )

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

    cleared = Op.SSTORE.with_metadata(
        key_warm=True,
        original_value=0,
        current_value=1,
        new_value=0,
    )
    # The account creation still outweighs the repayment, so `gas_left`
    # falls across the clearing window.
    post = {
        holder: Account(storage={SLOT_X: 0}),
        contract: Account(
            storage={
                SLOT_MARKER: 1,
                SLOT_INCREASED: 0,
                SLOT_RESULT: -cleared.state_refund(fork),
            }
        ),
    }
    state_test(pre=pre, post=post, tx=tx)

Parametrized Test Cases

This test generates 2 parametrized test cases across 1 fork.