Trio 0.16.0 (2020-06-10)

Headline features

- If you want to use Trio, but are stuck with some other event loop like

Qt or PyGame, then good news: now you can have both. For details, see:

:ref:`guest-mode`. (`#399 <https://github.com/python-trio/trio/issues/399>`__)

Features

- To speed up `trio.to_thread.run_sync`, Trio now caches and re-uses

worker threads.

And in case you have some exotic use case where you need to spawn

threads manually, but want to take advantage of Trio's cache, you can

do that using the new `trio.lowlevel.start_thread_soon`. (`#6 <https://github.com/python-trio/trio/issues/6>`__)

- Tasks spawned with `nursery.start() <trio.Nursery.start>` aren't treated as

direct children of their nursery until they call ``task_status.started()``.

This is visible through the task tree introspection attributes such as

`Task.parent_nursery <trio.lowlevel.Task.parent_nursery>`. Sometimes, though,

you want to know where the task is going to wind up, even if it hasn't finished

initializing yet. To support this, we added a new attribute

`Task.eventual_parent_nursery <trio.lowlevel.Task.eventual_parent_nursery>`.

For a task spawned with :meth:`~trio.Nursery.start` that hasn't yet called

``started()``, this is the nursery that the task was nominally started in,

where it will be running once it finishes starting up. In all other cases,

it is ``None``. (`#1558 <https://github.com/python-trio/trio/issues/1558>`__)

Bugfixes

- Added a helpful error message if an async function is passed to `trio.to_thread.run_sync`. (`#1573 <https://github.com/python-trio/trio/issues/1573>`__)

Deprecations and removals

- Remove ``BlockingTrioPortal``: it was deprecated in 0.12.0. (`#1574 <https://github.com/python-trio/trio/issues/1574>`__)

- The ``tiebreaker`` argument to `trio.testing.wait_all_tasks_blocked`

has been deprecated. This is a highly obscure feature that was

probably never used by anyone except `trio.testing.MockClock`, and

`~trio.testing.MockClock` doesn't need it anymore. (`#1587 <https://github.com/python-trio/trio/issues/1587>`__)

- Remove the deprecated ``trio.ssl`` and ``trio.subprocess`` modules. (`#1594 <https://github.com/python-trio/trio/issues/1594>`__)

Miscellaneous internal changes

- We refactored `trio.testing.MockClock` so that it no longer needs to

run an internal task to manage autojumping. This should be mostly

invisible to users, but there is one semantic change: the interaction

between `trio.testing.wait_all_tasks_blocked` and the autojump clock

was fixed. Now, the autojump will always wait until after all

`~trio.testing.wait_all_tasks_blocked` calls have finished before

firing, instead of it depending on which threshold values you passed. (`#1587 <https://github.com/python-trio/trio/issues/1587>`__)

__version__ = "0.16.0"