test_top_frame_charges_delegation_is_recipient()

Documentation for tests/amsterdam/eip2780_reduce_intrinsic_tx_gas/test_warmth_invariants.py::test_top_frame_charges_delegation_is_recipient@5c024cbb.

Generate fixtures for these test cases for Amsterdam with:

fill -v tests/amsterdam/eip2780_reduce_intrinsic_tx_gas/test_warmth_invariants.py::test_top_frame_charges_delegation_is_recipient --fork Amsterdam

Recipient holds a pre-existing EIP-7702 delegation pointing back at itself. The delegation target is the recipient, which is warm, so the top-frame charges WARM_ACCESS, and then the dispatched EVM frame runs the recipient's code -- which is the delegation prefix 0xef 01 00 <addr>. The leading 0xef decodes as the INVALID opcode, consuming the remaining EVM budget. The intrinsic and top-frame gas remain paid; the value transfer is rolled back.

Source code in tests/amsterdam/eip2780_reduce_intrinsic_tx_gas/test_warmth_invariants.py

@pytest.mark.parametrize(
    "value",
    [
        pytest.param(0, id="zero_value"),
        pytest.param(1, id="non-zero_value"),
    ],
)
def test_top_frame_charges_delegation_is_recipient(
    fork: Fork,
    pre: Alloc,
    state_test: StateTestFiller,
    value: int,
) -> None:
    """
    Recipient holds a pre-existing EIP-7702 delegation pointing back
    at itself. The delegation target is the recipient, which is warm,
    so the top-frame charges ``WARM_ACCESS``, and then the dispatched
    EVM frame runs the recipient's code -- which *is* the delegation
    prefix ``0xef 01 00 <addr>``. The leading ``0xef`` decodes as the
    ``INVALID`` opcode, consuming the remaining EVM budget. The
    intrinsic and top-frame gas remain paid; the value transfer is
    rolled back.
    """
    sender_initial_balance = 10**18
    sender = pre.fund_eoa(sender_initial_balance)

    # Pre-allocate an EOA that delegates to itself. The 1-wei balance
    # keeps the account alive at top-frame check time so the
    # ``NEW_ACCOUNT`` charge does not fire.
    target = pre.fund_eoa(amount=1, delegation="Self")
    target_code = Spec7702.delegation_designation(target)

    intrinsic_gas = fork.transaction_intrinsic_cost_calculator()(
        sends_value=bool(value),
        recipient_type=RecipientType.DELEGATION_7702,
        return_cost_deducted_prior_execution=True,
    )
    top_frame_gas = fork.transaction_top_frame_gas_calculator()(
        sends_value=bool(value),
        recipient_type=RecipientType.DELEGATION_7702,
        delegation_warm=True,
    )

    # The dispatched frame burns the entire EVM budget on the
    # ``INVALID`` opcode and the value transfer is rolled back, so the
    # sender pays the full ``gas_limit``.
    gas_price = 1_000_000_000
    gas_limit = intrinsic_gas + top_frame_gas + 50_000

    tx = Transaction(
        sender=sender,
        to=target,
        value=value,
        gas_limit=gas_limit,
        gas_price=gas_price,
    )

    sender_final_balance = sender_initial_balance - gas_limit * gas_price

    post = {
        sender: Account(nonce=1, balance=sender_final_balance),
        # Value transfer rolled back by the ``INVALID``; the pre-tx
        # 1-wei balance is preserved.
        target: Account(balance=1, code=target_code),
    }

    state_test(pre=pre, tx=tx, post=post)

Parametrized Test Cases

This test generates 2 parametrized test cases across 1 fork.