test_bal_cross_tx_balance_dependency()

Documentation for tests/amsterdam/eip7928_block_level_access_lists/test_block_access_lists.py::test_bal_cross_tx_balance_dependency@622620d8.

Generate fixtures for these test cases for Amsterdam with:

fill -v tests/amsterdam/eip7928_block_level_access_lists/test_block_access_lists.py::test_bal_cross_tx_balance_dependency --fork Amsterdam

Verify clients apply Tx1's balance change before executing Tx2 in the same block. Tx1 routes value into a contract; Tx2 invokes the contract which records its SELFBALANCE to storage. A client that parallelizes Tx2 without applying Tx1's balance_changes would record the pre-block balance, yielding a different state root. The selfdestruct variant routes the funds via SELFDESTRUCT from a pre-funded killer contract so the recipient's bytecode never runs in Tx1 — catching any client optimization that ties balance tracking to code execution.

Source code in tests/amsterdam/eip7928_block_level_access_lists/test_block_access_lists.py

@pytest.mark.parametrize(
    "funding_method",
    ["direct_call", "selfdestruct"],
)
def test_bal_cross_tx_balance_dependency(
    pre: Alloc,
    blockchain_test: BlockchainTestFiller,
    funding_method: str,
) -> None:
    """
    Verify clients apply Tx1's balance change before executing Tx2 in
    the same block. Tx1 routes value into a contract; Tx2 invokes the
    contract which records its `SELFBALANCE` to storage. A client that
    parallelizes Tx2 without applying Tx1's `balance_changes` would
    record the pre-block balance, yielding a different state root. The
    `selfdestruct` variant routes the funds via SELFDESTRUCT from a
    pre-funded killer contract so the recipient's bytecode never runs
    in Tx1 — catching any client optimization that ties balance
    tracking to code execution.
    """
    transferred = 1
    alice = pre.fund_eoa()
    bob = pre.fund_eoa()

    # Any non-empty calldata triggers the SELFBALANCE record path;
    # empty calldata is the value-receiver path.
    contract = pre.deploy_contract(
        code=Conditional(
            condition=Op.ISZERO(Op.CALLDATASIZE),
            if_true=Op.STOP,
            if_false=Op.SSTORE(0, Op.SELFBALANCE),
        ),
    )

    if funding_method == "direct_call":
        tx_send = Transaction(sender=alice, to=contract, value=transferred)
        send_expectations: dict = {}
    elif funding_method == "selfdestruct":
        killer = pre.deploy_contract(
            code=Op.SELFDESTRUCT(contract),
            balance=transferred,
        )
        tx_send = Transaction(sender=alice, to=killer)
        send_expectations = {
            killer: BalAccountExpectation(
                balance_changes=[
                    BalBalanceChange(block_access_index=1, post_balance=0),
                ],
            ),
        }
    else:
        raise ValueError(f"unknown funding_method: {funding_method}")

    tx_read = Transaction(sender=bob, to=contract, data=b"\x01")

    account_expectations = {
        contract: BalAccountExpectation(
            balance_changes=[
                BalBalanceChange(
                    block_access_index=1, post_balance=transferred
                ),
            ],
            storage_changes=[
                BalStorageSlot(
                    slot=0,
                    slot_changes=[
                        BalStorageChange(
                            block_access_index=2, post_value=transferred
                        ),
                    ],
                ),
            ],
        ),
        **send_expectations,
    }

    blockchain_test(
        pre=pre,
        blocks=[
            Block(
                txs=[tx_send, tx_read],
                expected_block_access_list=BlockAccessListExpectation(
                    account_expectations=account_expectations
                ),
            )
        ],
        post={
            contract: Account(balance=transferred, storage={0: transferred}),
        },
    )

Parametrized Test Cases

This test generates 2 parametrized test cases across 1 fork.