- update to 0.27.0:
* :func:`trio.move_on_after` and :func:`trio.fail_after`
previously set the deadline relative to initialization time,
instead of more intuitively upon entering the context
manager. This might change timeouts if a program relied on
this behavior. If you want to restore previous behavior you
should instead use trio.move_on_at(trio.current_time() +
...). flake8-async has a new rule to catch this, in case
you're supporting older trio versions. See :ref:`ASYNC122`.
* :meth:`CancelScope.relative_deadline` and
:meth:`CancelScope.is_relative` added, as well as a
relative_deadline parameter to __init__. This allows
initializing scopes ahead of time, but where the specified
relative deadline doesn't count down until the scope is
entered.
* :class:`trio.Lock` and :class:`trio.StrictFIFOLock` will now
raise :exc:`trio.BrokenResourceError` when
:meth:`trio.Lock.acquire` would previously stall due to the
owner of the lock exiting without releasing the lock.
* trio.move_on_at, trio.move_on_after, trio.fail_at and
trio.fail_after now accept shield as a keyword argument. If
specified, it provides an initial value for the
~trio.CancelScope.shield attribute of the trio.CancelScope
object created by the context manager.
* Added :func:`trio.lowlevel.add_parking_lot_breaker` and
:func:`trio.lowlevel.remove_parking_lot_breaker` to allow
creating custom lock/semaphore implementations that will
break their underlying parking lot if a task exits
unexpectedly. :meth:`trio.lowlevel.ParkingLot.break_lot` is
also added, to allow breaking a parking lot intentionally.