test_coinbase_fee_with_state_gas_refund()

Documentation for tests/amsterdam/eip8037_state_creation_gas_cost_increase/test_state_gas_multi_block.py::test_coinbase_fee_with_state_gas_refund@622620d8.

Generate fixtures for these test cases for Amsterdam with:

fill -v tests/amsterdam/eip8037_state_creation_gas_cost_increase/test_state_gas_multi_block.py::test_coinbase_fee_with_state_gas_refund --fork Amsterdam

Assert the coinbase is paid on the post-refund gas, not the charge.

A 0 to x to 0 cycle refunds its state charge to the reservoir, so the sender is billed execution gas alone and the miner is paid on that same figure. Paying the miner on the pre-refund total would hand it the whole storage set for free.

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

@pytest.mark.valid_from("EIP8037")
def test_coinbase_fee_with_state_gas_refund(
    blockchain_test: BlockchainTestFiller,
    pre: Alloc,
    fork: Fork,
) -> None:
    """
    Assert the coinbase is paid on the post-refund gas, not the charge.

    A 0 to x to 0 cycle refunds its state charge to the reservoir, so
    the sender is billed execution gas alone and the miner is paid on
    that same figure. Paying the miner on the pre-refund total would
    hand it the whole storage set for free.
    """
    cycle_code = Op.SSTORE(0, 1) + Op.SSTORE(
        0,
        0,
        # gas accounting
        key_warm=True,
        original_value=0,
        current_value=1,
        new_value=0,
    )
    sstore_state_gas = Op.SSTORE(new_value=1).state_cost(fork)
    cycle = pre.deploy_contract(code=cycle_code)

    # The cycle nets to no state growth, so only execution gas is billed,
    # less the write-cost refund the restoration earns (capped at the
    # usual fraction of the pre-refund total).
    pre_refund_gas = (
        fork.transaction_intrinsic_cost_calculator()()
        + cycle_code.execution_cost(fork)
    )
    execution_refund = cycle_code.refund(fork) - cycle_code.state_refund(fork)
    expected_coinbase = pre_refund_gas - min(
        pre_refund_gas // fork.max_refund_quotient(), execution_refund
    )

    reporter_storage = Storage()
    reporter = pre.deploy_contract(
        code=(
            Op.SSTORE(
                reporter_storage.store_next(expected_coinbase, "coinbase"),
                Op.BALANCE(Op.COINBASE),
            )
        ),
    )

    blockchain_test(
        pre=pre,
        blocks=[
            Block(
                txs=[
                    Transaction(
                        to=cycle,
                        state_gas_reservoir=sstore_state_gas,
                        max_priority_fee_per_gas=1,
                        max_fee_per_gas=8,
                        sender=pre.fund_eoa(),
                    ),
                    Transaction(
                        to=reporter,
                        state_gas_reservoir=0,
                        max_priority_fee_per_gas=1,
                        max_fee_per_gas=8,
                        sender=pre.fund_eoa(),
                    ),
                ],
            )
        ],
        post={
            cycle: Account(storage={0: 0}),
            reporter: Account(storage=reporter_storage),
        },
    )

Parametrized Test Cases

This test generates 1 parametrized test case across 1 fork.