test_bal_storage_write_read_cross_frame()

Documentation for tests/amsterdam/eip7928_block_level_access_lists/test_block_access_lists_opcodes.py::test_bal_storage_write_read_cross_frame@892e6d1e.

Generate fixtures for these test cases for Amsterdam with:

fill -v tests/amsterdam/eip7928_block_level_access_lists/test_block_access_lists_opcodes.py::test_bal_storage_write_read_cross_frame --fork Amsterdam

Ensure BAL captures write precedence over read across call frames.

Frame 1: Read slot 0x01 (0x99), write 0x42, then call itself. Frame 2: Read slot 0x01 (0x42), see it's 0x42 and return. Both reads are shadowed by the write - only write appears in BAL.

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

@pytest.mark.parametrize(
    "call_opcode",
    [
        pytest.param(
            lambda target: Op.CALL(100_000, target, 0, 0, 0, 0, 0), id="call"
        ),
        pytest.param(
            lambda target: Op.DELEGATECALL(100_000, target, 0, 0, 0, 0),
            id="delegatecall",
        ),
        pytest.param(
            lambda target: Op.CALLCODE(100_000, target, 0, 0, 0, 0, 0),
            id="callcode",
        ),
    ],
)
def test_bal_storage_write_read_cross_frame(
    pre: Alloc,
    blockchain_test: BlockchainTestFiller,
    call_opcode: Callable[[Bytecode], Bytecode],
) -> None:
    """
    Ensure BAL captures write precedence over read across call frames.

    Frame 1: Read slot 0x01 (0x99), write 0x42, then call itself.
    Frame 2: Read slot 0x01 (0x42), see it's 0x42 and return.
    Both reads are shadowed by the write - only write appears in BAL.
    """
    alice = pre.fund_eoa()

    # Oracle code:
    # 1. Read slot 0x01 (initial: 0x99, recursive: 0x42)
    # 2. If value == 0x42, return (exit recursion)
    # 3. Write 0x42 to slot 0x01
    # 4. Call itself recursively
    oracle_code = (
        Op.SLOAD(0x01)  # Load value from slot 0x01
        + Op.PUSH1(0x42)  # Push 0x42 for comparison
        + Op.EQ  # Check if loaded value == 0x42
        + Op.PUSH1(0x1D)  # Jump destination (after SSTORE + CALL)
        + Op.JUMPI  # If equal, jump to end (exit recursion)
        + Op.PUSH1(0x42)  # Value to write
        + Op.PUSH1(0x01)  # Slot 0x01
        + Op.SSTORE  # Write 0x42 to slot 0x01
        + call_opcode(Op.ADDRESS)  # Call itself
        + Op.JUMPDEST  # Jump destination for exit
        + Op.STOP
    )

    oracle = pre.deploy_contract(code=oracle_code, storage={0x01: 0x99})

    tx = Transaction(
        sender=alice,
        to=oracle,
        gas_limit=1_000_000,
    )

    block = Block(
        txs=[tx],
        expected_block_access_list=BlockAccessListExpectation(
            account_expectations={
                alice: BalAccountExpectation(
                    nonce_changes=[
                        BalNonceChange(block_access_index=1, post_nonce=1)
                    ],
                ),
                oracle: BalAccountExpectation(
                    storage_changes=[
                        BalStorageSlot(
                            slot=0x01,
                            slot_changes=[
                                BalStorageChange(
                                    block_access_index=1, post_value=0x42
                                )
                            ],
                        )
                    ],
                    storage_reads=[],  # Empty! Write shadows both reads
                ),
            }
        ),
    )

    blockchain_test(
        pre=pre,
        blocks=[block],
        post={
            alice: Account(nonce=1),
            oracle: Account(storage={0x01: 0x42}),
        },
    )

Parametrized Test Cases

This test generates 3 parametrized test cases across 1 fork.