Stop allowing subclassing public classes

It was deprecated in Trio 0.15.0.

Author: pquentin

newsfragments/1726.deprecated.rst

@@ -0,0 +1 @@
+Stop allowing subclassing public classes. This behavior was deprecated in 0.15.0.

trio/_core/_local.py

@@ -1,7 +1,7 @@
 # Runvar implementations
 from . import _run
 
-from .._util import SubclassingDeprecatedIn_v0_15_0
+from .._util import Final
 
 
 class _RunVarToken:
@@ -19,7 +19,7 @@ def __init__(self, var, value):
         self.redeemed = False
 
 
-class RunVar(metaclass=SubclassingDeprecatedIn_v0_15_0):
+class RunVar(metaclass=Final):
     """The run-local variant of a context variable.
 
     :class:`RunVar` objects are similar to context variable objects,

trio/_core/_mock_clock.py

@@ -4,7 +4,7 @@
 from .. import _core
 from ._run import GLOBAL_RUN_CONTEXT
 from .._abc import Clock
-from .._util import SubclassingDeprecatedIn_v0_15_0
+from .._util import Final
 
 ################################################################
 # The glorious MockClock
@@ -14,7 +14,7 @@
 # Prior art:
 #   https://twistedmatrix.com/documents/current/api/twisted.internet.task.Clock.html
 #   https://github.com/ztellman/manifold/issues/57
-class MockClock(Clock, metaclass=SubclassingDeprecatedIn_v0_15_0):
+class MockClock(Clock, metaclass=Final):
     """A user-controllable clock suitable for writing tests.
 
     Args:

trio/_core/_parking_lot.py

@@ -75,7 +75,7 @@
 from collections import OrderedDict
 
 from .. import _core
-from .._util import SubclassingDeprecatedIn_v0_15_0
+from .._util import Final
 
 _counter = count()
 
@@ -86,7 +86,7 @@ class _ParkingLotStatistics:
 
 
 @attr.s(eq=False, hash=False)
-class ParkingLot(metaclass=SubclassingDeprecatedIn_v0_15_0):
+class ParkingLot(metaclass=Final):
     """A fair wait queue with cancellation and requeueing.
 
     This class encapsulates the tricky parts of implementing a wait

trio/_core/_unbounded_queue.py

@@ -2,7 +2,7 @@
 
 from .. import _core
 from .._deprecate import deprecated
-from .._util import SubclassingDeprecatedIn_v0_15_0
+from .._util import Final
 
 
 @attr.s(frozen=True)
@@ -11,7 +11,7 @@ class _UnboundedQueueStats:
     tasks_waiting = attr.ib()
 
 
-class UnboundedQueue(metaclass=SubclassingDeprecatedIn_v0_15_0):
+class UnboundedQueue(metaclass=Final):
     """An unbounded queue suitable for certain unusual forms of inter-task
     communication.
 

trio/_highlevel_generic.py

@@ -3,7 +3,7 @@
 import trio
 from .abc import HalfCloseableStream
 
-from trio._util import SubclassingDeprecatedIn_v0_15_0
+from trio._util import Final
 
 
 async def aclose_forcefully(resource):
@@ -37,7 +37,7 @@ async def aclose_forcefully(resource):
 
 
 @attr.s(eq=False, hash=False)
-class StapledStream(HalfCloseableStream, metaclass=SubclassingDeprecatedIn_v0_15_0):
+class StapledStream(HalfCloseableStream, metaclass=Final):
     """This class `staples <https://en.wikipedia.org/wiki/Staple_(fastener)>`__
     together two unidirectional streams to make single bidirectional stream.
 

trio/_highlevel_socket.py

@@ -5,7 +5,7 @@
 
 import trio
 from . import socket as tsocket
-from ._util import ConflictDetector, SubclassingDeprecatedIn_v0_15_0
+from ._util import ConflictDetector, Final
 from .abc import HalfCloseableStream, Listener
 
 # XX TODO: this number was picked arbitrarily. We should do experiments to
@@ -35,7 +35,7 @@ def _translate_socket_errors_to_stream_errors():
             ) from exc
 
 
-class SocketStream(HalfCloseableStream, metaclass=SubclassingDeprecatedIn_v0_15_0):
+class SocketStream(HalfCloseableStream, metaclass=Final):
     """An implementation of the :class:`trio.abc.HalfCloseableStream`
     interface based on a raw network socket.
 
@@ -315,7 +315,7 @@ def getsockopt(self, level, option, buffersize=0):
         pass
 
 
-class SocketListener(Listener[SocketStream], metaclass=SubclassingDeprecatedIn_v0_15_0):
+class SocketListener(Listener[SocketStream], metaclass=Final):
     """A :class:`~trio.abc.Listener` that uses a listening socket to accept
     incoming connections as :class:`SocketStream` objects.
 

trio/_path.py

@@ -6,7 +6,7 @@
 import pathlib
 
 import trio
-from trio._util import async_wraps, SubclassingDeprecatedIn_v0_15_0
+from trio._util import async_wraps, Final
 
 
 # re-wrap return value from methods that return new instances of pathlib.Path
@@ -77,7 +77,7 @@ async def wrapper(cls, *args, **kwargs):
     return wrapper
 
 
-class AsyncAutoWrapperType(SubclassingDeprecatedIn_v0_15_0):
+class AsyncAutoWrapperType(Final):
     def __init__(cls, name, bases, attrs):
         super().__init__(name, bases, attrs)
 

trio/_ssl.py

@@ -158,7 +158,7 @@
 from .abc import Stream, Listener
 from ._highlevel_generic import aclose_forcefully
 from . import _sync
-from ._util import ConflictDetector, SubclassingDeprecatedIn_v0_15_0
+from ._util import ConflictDetector, Final
 from ._deprecate import warn_deprecated
 
 ################################################################
@@ -224,7 +224,7 @@ def done(self):
 _State = _Enum("_State", ["OK", "BROKEN", "CLOSED"])
 
 
-class SSLStream(Stream, metaclass=SubclassingDeprecatedIn_v0_15_0):
+class SSLStream(Stream, metaclass=Final):
     r"""Encrypted communication using SSL/TLS.
 
     :class:`SSLStream` wraps an arbitrary :class:`~trio.abc.Stream`, and
@@ -870,7 +870,7 @@ async def wait_send_all_might_not_block(self):
                 await self.transport_stream.wait_send_all_might_not_block()
 
 
-class SSLListener(Listener[SSLStream], metaclass=SubclassingDeprecatedIn_v0_15_0):
+class SSLListener(Listener[SSLStream], metaclass=Final):
     """A :class:`~trio.abc.Listener` for SSL/TLS-encrypted servers.
 
     :class:`SSLListener` wraps around another Listener, and converts

trio/_sync.py

@@ -7,11 +7,11 @@
 
 from ._core import enable_ki_protection, ParkingLot
 from ._deprecate import deprecated
-from ._util import SubclassingDeprecatedIn_v0_15_0
+from ._util import Final
 
 
 @attr.s(repr=False, eq=False, hash=False)
-class Event(metaclass=SubclassingDeprecatedIn_v0_15_0):
+class Event(metaclass=Final):
     """A waitable boolean value useful for inter-task synchronization,
     inspired by :class:`threading.Event`.
 
@@ -99,7 +99,7 @@ class _CapacityLimiterStatistics:
 
 
 @async_cm
-class CapacityLimiter(metaclass=SubclassingDeprecatedIn_v0_15_0):
+class CapacityLimiter(metaclass=Final):
     """An object for controlling access to a resource with limited capacity.
 
     Sometimes you need to put a limit on how many tasks can do something at
@@ -342,7 +342,7 @@ def statistics(self):
 
 
 @async_cm
-class Semaphore(metaclass=SubclassingDeprecatedIn_v0_15_0):
+class Semaphore(metaclass=Final):
     """A `semaphore <https://en.wikipedia.org/wiki/Semaphore_(programming)>`__.
 
     A semaphore holds an integer value, which can be incremented by
@@ -562,7 +562,7 @@ def statistics(self):
         )
 
 
-class Lock(_LockImpl, metaclass=SubclassingDeprecatedIn_v0_15_0):
+class Lock(_LockImpl, metaclass=Final):
     """A classic `mutex
     <https://en.wikipedia.org/wiki/Lock_(computer_science)>`__.
 
@@ -576,7 +576,7 @@ class Lock(_LockImpl, metaclass=SubclassingDeprecatedIn_v0_15_0):
     """
 
 
-class StrictFIFOLock(_LockImpl, metaclass=SubclassingDeprecatedIn_v0_15_0):
+class StrictFIFOLock(_LockImpl, metaclass=Final):
     r"""A variant of :class:`Lock` where tasks are guaranteed to acquire the
     lock in strict first-come-first-served order.
 
@@ -646,7 +646,7 @@ class _ConditionStatistics:
 
 
 @async_cm
-class Condition(metaclass=SubclassingDeprecatedIn_v0_15_0):
+class Condition(metaclass=Final):
     """A classic `condition variable
     <https://en.wikipedia.org/wiki/Monitor_(synchronization)>`__, similar to
     :class:`threading.Condition`.