test_repeated_create_same_code_charges_each_account()

Documentation for tests/amsterdam/eip8037_state_creation_gas_cost_increase/test_state_gas_create.py::test_repeated_create_same_code_charges_each_account@622620d8.

Generate fixtures for these test cases for Amsterdam with:

fill -v tests/amsterdam/eip8037_state_creation_gas_cost_increase/test_state_gas_create.py::test_repeated_create_same_code_charges_each_account --fork Amsterdam

Test code deposit is charged per-account, not per code hash.

Two CREATEs with identical init code deploy identical bytecode and so share a single code_hash. The factory snapshots gas_left around each CREATE via Op.GAS and stores (g0 - g1) - (g1 - g2) in slot 0. Identical work must cost the same — so the difference must be zero.

Runtime measurement is required: the bug manifests as a child-frame state-gas spillover into gas_left (a runtime quantity), which static helpers like bytecode.gas_cost() do not model.

A non-zero result indicates compute_state_byte_diff is keying code-deposit accounting by hash via code_writes, silently dropping the second CREATE's len(code) × CPSB charge.

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

@pytest.mark.valid_from("EIP8037")
def test_repeated_create_same_code_charges_each_account(
    state_test: StateTestFiller,
    pre: Alloc,
) -> None:
    """
    Test code deposit is charged per-account, not per code hash.

    Two CREATEs with identical init code deploy identical bytecode
    and so share a single ``code_hash``. The factory snapshots
    ``gas_left`` around each CREATE via ``Op.GAS`` and stores
    ``(g0 - g1) - (g1 - g2)`` in slot 0. Identical work must cost
    the same — so the difference must be zero.

    Runtime measurement is required: the bug manifests as a
    child-frame state-gas spillover into ``gas_left`` (a runtime
    quantity), which static helpers like ``bytecode.gas_cost()``
    do not model.

    A non-zero result indicates ``compute_state_byte_diff`` is
    keying code-deposit accounting by hash via ``code_writes``,
    silently dropping the second CREATE's ``len(code) × CPSB``
    charge.
    """
    # Y init code returns memory[0:1] = 0x00 to deploy a 1-byte STOP.
    y_init = Op.PUSH1(1) + Op.PUSH1(0) + Op.RETURN
    y_size = len(bytes(y_init))

    # Memory layout:
    #   [ 0: 32) — Y init code (right-aligned PUSH32 padding)
    #   [32: 64) — g0 (gas before first CREATE)
    #   [64: 96) — g1 (gas between the two CREATEs)
    #   [96:128) — g2 (gas after second CREATE)
    factory_code = (
        Op.MSTORE(0, Op.PUSH32(bytes(y_init)))
        + Op.MSTORE(32, Op.GAS)
        + Op.POP(Op.CREATE(value=0, offset=32 - y_size, size=y_size))
        + Op.MSTORE(64, Op.GAS)
        + Op.POP(Op.CREATE(value=0, offset=32 - y_size, size=y_size))
        + Op.MSTORE(96, Op.GAS)
        + Op.SSTORE(
            0,
            Op.SUB(
                Op.SUB(Op.MLOAD(32), Op.MLOAD(64)),  # cost of CREATE 1
                Op.SUB(Op.MLOAD(64), Op.MLOAD(96)),  # cost of CREATE 2
            ),
        )
        + Op.STOP
    )

    factory_storage = Storage()
    factory_storage[0] = 0
    factory = pre.deploy_contract(code=factory_code, storage=factory_storage)

    tx = Transaction(
        to=factory,
        sender=pre.fund_eoa(),
        gas_limit=2_000_000,
    )

    state_test(
        pre=pre,
        post={factory: Account(storage=factory_storage)},
        tx=tx,
    )

Parametrized Test Cases

This test generates 1 parametrized test case across 1 fork.