test_delegatecall_reservoir_passing()

Documentation for tests/amsterdam/eip8037_state_creation_gas_cost_increase/test_state_gas_call.py::test_delegatecall_reservoir_passing@622620d8.

Generate fixtures for these test cases for Amsterdam with:

fill -v tests/amsterdam/eip8037_state_creation_gas_cost_increase/test_state_gas_call.py::test_delegatecall_reservoir_passing --fork Amsterdam

Test DELEGATECALL passes full reservoir to child.

DELEGATECALL runs child code in the caller's storage context. The child's SSTORE writes to the parent's storage using state gas from the reservoir, emptying it. A probe handed only its SSTORE's execution cost then fails, proving the draw was real.

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

@pytest.mark.valid_from("EIP8037")
def test_delegatecall_reservoir_passing(
    state_test: StateTestFiller,
    pre: Alloc,
    fork: Fork,
) -> None:
    """
    Test DELEGATECALL passes full reservoir to child.

    DELEGATECALL runs child code in the caller's storage context.
    The child's SSTORE writes to the parent's storage using state gas
    from the reservoir, emptying it. A probe handed only its SSTORE's
    execution cost then fails, proving the draw was real.
    """
    sstore_state_gas = Op.SSTORE(new_value=1).state_cost(fork)

    parent_storage = Storage()
    # Library code runs in parent's context — slot is reserved on
    # parent_storage so the post check uses the same source of truth.
    library_code = Op.SSTORE(parent_storage.store_next(1), 1)
    library = pre.deploy_contract(code=library_code)

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

    probe_slot = parent_storage.store_next(0, "probe_fails")
    parent_code = Op.POP(
        Op.DELEGATECALL(gas=library_code.execution_cost(fork), address=library)
    ) + Op.SSTORE(
        probe_slot,
        Op.CALL(gas=probe_gas, address=probe),
        # gas accounting
        original_value=1,
        current_value=1,
        new_value=0,
        key_warm=False,
    )
    parent = pre.deploy_contract(code=parent_code, storage={probe_slot: 1})

    tx = Transaction(
        to=parent,
        state_gas_reservoir=sstore_state_gas,
        sender=pre.fund_eoa(),
    )

    post = {
        parent: Account(storage=parent_storage),
        probe: Account(storage={0: 0}),
    }
    state_test(pre=pre, post=post, tx=tx)

Parametrized Test Cases

This test generates 1 parametrized test case across 1 fork.