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test_call_memory_expands_on_early_revert()

Documentation for tests/frontier/opcodes/test_call.py::test_call_memory_expands_on_early_revert@88e9fb8f.

Generate fixtures for these test cases for Osaka with:

fill -v tests/frontier/opcodes/test_call.py::test_call_memory_expands_on_early_revert --fork Osaka

When CALL reverts early (e.g. because of not enough balance by the sender), memory should be expanded anyway. We check this with an MSTORE.

This is for a bug in an EVM implementation where memory is expanded after executing a CALL, but not when an early revert happens.

Source code in tests/frontier/opcodes/test_call.py 
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@pytest.mark.valid_from("Berlin")
def test_call_memory_expands_on_early_revert(
    state_test: StateTestFiller,
    pre: Alloc,
    fork: Fork,
) -> None:
    """
    When CALL reverts early (e.g. because of not enough balance by the sender),
    memory should be expanded anyway. We check this with an MSTORE.

    This is for a bug in an EVM implementation where memory is expanded after
    executing a CALL, but not when an early revert happens.
    """
    sender = pre.fund_eoa()

    gsc = fork.gas_costs()
    # arbitrary number, greater than memory size to trigger an expansion
    ret_size = 128

    call_measure = CodeGasMeasure(
        # CALL with value
        code=Op.CALL(gas=0, value=100, ret_size=ret_size),
        # Cost of pushing CALL args
        overhead_cost=gsc.G_VERY_LOW * len(Op.CALL.kwargs),
        # Because CALL pushes 1 item to the stack
        extra_stack_items=1,
        sstore_key=0,
        # Because it's the first CodeGasMeasure
        stop=False,
    )
    mstore_measure = CodeGasMeasure(
        # Low offset for not expanding memory
        code=Op.MSTORE(offset=ret_size // 2, value=1),
        # Cost of pushing MSTORE args
        overhead_cost=gsc.G_VERY_LOW * len(Op.MSTORE.kwargs),
        extra_stack_items=0,
        sstore_key=1,
    )

    # Contract without enough balance to send value transfer
    contract = pre.deploy_contract(code=call_measure + mstore_measure, balance=0)

    tx = Transaction(
        gas_limit=500_000,
        to=contract,
        value=0,
        sender=sender,
    )

    memory_expansion_gas_calc = fork.memory_expansion_gas_calculator()
    # call cost:
    #   address_access_cost+new_acc_cost+memory_expansion_cost+value-stipend
    call_cost = (
        gsc.G_COLD_ACCOUNT_ACCESS
        + gsc.G_NEW_ACCOUNT
        + memory_expansion_gas_calc(new_bytes=ret_size)
        + gsc.G_CALL_VALUE
        - gsc.G_CALL_STIPEND
    )

    # mstore cost: base cost. No memory expansion cost needed, it was expanded
    # on CALL.
    mstore_cost = gsc.G_MEMORY
    state_test(
        env=Environment(),
        pre=pre,
        tx=tx,
        post={
            contract: Account(
                storage={
                    0: call_cost,
                    1: mstore_cost,
                },
            )
        },
    )

Parametrized Test Cases

This test case is only parametrized by fork and fixture format.

Test ID (Abbreviated)
...fork_Berlin-state_test
...fork_Berlin-blockchain_test_from_state_test
...fork_London-state_test
...fork_London-blockchain_test_from_state_test
...fork_Paris-state_test
...fork_Paris-blockchain_test_from_state_test
...fork_Shanghai-state_test
...fork_Shanghai-blockchain_test_from_state_test
...fork_Cancun-state_test
...fork_Cancun-blockchain_test_from_state_test
...fork_Prague-state_test
...fork_Prague-blockchain_test_from_state_test
...fork_Osaka-state_test
...fork_Osaka-blockchain_test_from_state_test