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bpo-29617: Remove Python 3.3 support from asyncio (GH-232)

This commit is contained in:
INADA Naoki 2017-04-25 10:57:18 +09:00 committed by GitHub
parent f6448e5d65
commit 3e2ad8ec61
12 changed files with 65 additions and 223 deletions
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17
Lib/asyncio/base_events.py
View File

@ -29,7 +29,6 @@ import sys
import warnings
import weakref
from . import compat
from . import coroutines
from . import events
from . import futures
@ -499,16 +498,12 @@ class BaseEventLoop(events.AbstractEventLoop):
"""Returns True if the event loop was closed."""
return self._closed
# On Python 3.3 and older, objects with a destructor part of a reference
# cycle are never destroyed. It's not more the case on Python 3.4 thanks
# to the PEP 442.
if compat.PY34:
def __del__(self):
if not self.is_closed():
warnings.warn("unclosed event loop %r" % self, ResourceWarning,
source=self)
if not self.is_running():
self.close()
def __del__(self):
if not self.is_closed():
warnings.warn("unclosed event loop %r" % self, ResourceWarning,
source=self)
if not self.is_running():
self.close()
def is_running(self):
"""Returns True if the event loop is running."""

15
Lib/asyncio/base_subprocess.py
View File

@ -2,7 +2,6 @@ import collections
import subprocess
import warnings
from . import compat
from . import protocols
from . import transports
from .coroutines import coroutine
@ -121,15 +120,11 @@ class BaseSubprocessTransport(transports.SubprocessTransport):
# Don't clear the _proc reference yet: _post_init() may still run
# On Python 3.3 and older, objects with a destructor part of a reference
# cycle are never destroyed. It's not more the case on Python 3.4 thanks
# to the PEP 442.
if compat.PY34:
def __del__(self):
if not self._closed:
warnings.warn("unclosed transport %r" % self, ResourceWarning,
source=self)
self.close()
def __del__(self):
if not self._closed:
warnings.warn("unclosed transport %r" % self, ResourceWarning,
source=self)
self.close()
def get_pid(self):
return self._pid

12
Lib/asyncio/compat.py
View File

@ -2,17 +2,5 @@
import sys
PY34 = sys.version_info >= (3, 4)
PY35 = sys.version_info >= (3, 5)
PY352 = sys.version_info >= (3, 5, 2)
def flatten_list_bytes(list_of_data):
"""Concatenate a sequence of bytes-like objects."""
if not PY34:
# On Python 3.3 and older, bytes.join() doesn't handle
# memoryview.
list_of_data = (
bytes(data) if isinstance(data, memoryview) else data
for data in list_of_data)
return b''.join(list_of_data)

9
Lib/asyncio/events.py
View File

@ -19,20 +19,15 @@ import sys
import threading
import traceback
from asyncio import compat
def _get_function_source(func):
if compat.PY34:
func = inspect.unwrap(func)
elif hasattr(func, '__wrapped__'):
func = func.__wrapped__
func = inspect.unwrap(func)
if inspect.isfunction(func):
code = func.__code__
return (code.co_filename, code.co_firstlineno)
if isinstance(func, functools.partial):
return _get_function_source(func.func)
if compat.PY34 and isinstance(func, functools.partialmethod):
if isinstance(func, functools.partialmethod):
return _get_function_source(func.func)
return None

122
Lib/asyncio/futures.py
View File

@ -27,86 +27,6 @@ _FINISHED = base_futures._FINISHED
STACK_DEBUG = logging.DEBUG - 1 # heavy-duty debugging
class _TracebackLogger:
"""Helper to log a traceback upon destruction if not cleared.
This solves a nasty problem with Futures and Tasks that have an
exception set: if nobody asks for the exception, the exception is
never logged. This violates the Zen of Python: 'Errors should
never pass silently. Unless explicitly silenced.'
However, we don't want to log the exception as soon as
set_exception() is called: if the calling code is written
properly, it will get the exception and handle it properly. But
we *do* want to log it if result() or exception() was never called
-- otherwise developers waste a lot of time wondering why their
buggy code fails silently.
An earlier attempt added a __del__() method to the Future class
itself, but this backfired because the presence of __del__()
prevents garbage collection from breaking cycles. A way out of
this catch-22 is to avoid having a __del__() method on the Future
class itself, but instead to have a reference to a helper object
with a __del__() method that logs the traceback, where we ensure
that the helper object doesn't participate in cycles, and only the
Future has a reference to it.
The helper object is added when set_exception() is called. When
the Future is collected, and the helper is present, the helper
object is also collected, and its __del__() method will log the
traceback. When the Future's result() or exception() method is
called (and a helper object is present), it removes the helper
object, after calling its clear() method to prevent it from
logging.
One downside is that we do a fair amount of work to extract the
traceback from the exception, even when it is never logged. It
would seem cheaper to just store the exception object, but that
references the traceback, which references stack frames, which may
reference the Future, which references the _TracebackLogger, and
then the _TracebackLogger would be included in a cycle, which is
what we're trying to avoid! As an optimization, we don't
immediately format the exception; we only do the work when
activate() is called, which call is delayed until after all the
Future's callbacks have run. Since usually a Future has at least
one callback (typically set by 'yield from') and usually that
callback extracts the callback, thereby removing the need to
format the exception.
PS. I don't claim credit for this solution. I first heard of it
in a discussion about closing files when they are collected.
"""
__slots__ = ('loop', 'source_traceback', 'exc', 'tb')
def __init__(self, future, exc):
self.loop = future._loop
self.source_traceback = future._source_traceback
self.exc = exc
self.tb = None
def activate(self):
exc = self.exc
if exc is not None:
self.exc = None
self.tb = traceback.format_exception(exc.__class__, exc,
exc.__traceback__)
def clear(self):
self.exc = None
self.tb = None
def __del__(self):
if self.tb:
msg = 'Future/Task exception was never retrieved\n'
if self.source_traceback:
src = ''.join(traceback.format_list(self.source_traceback))
msg += 'Future/Task created at (most recent call last):\n'
msg += '%s\n' % src.rstrip()
msg += ''.join(self.tb).rstrip()
self.loop.call_exception_handler({'message': msg})
class Future:
"""This class is *almost* compatible with concurrent.futures.Future.
@ -164,25 +84,21 @@ class Future:
def __repr__(self):
return '<%s %s>' % (self.__class__.__name__, ' '.join(self._repr_info()))
# On Python 3.3 and older, objects with a destructor part of a reference
# cycle are never destroyed. It's not more the case on Python 3.4 thanks
# to the PEP 442.
if compat.PY34:
def __del__(self):
if not self._log_traceback:
# set_exception() was not called, or result() or exception()
# has consumed the exception
return
exc = self._exception
context = {
'message': ('%s exception was never retrieved'
% self.__class__.__name__),
'exception': exc,
'future': self,
}
if self._source_traceback:
context['source_traceback'] = self._source_traceback
self._loop.call_exception_handler(context)
def __del__(self):
if not self._log_traceback:
# set_exception() was not called, or result() or exception()
# has consumed the exception
return
exc = self._exception
context = {
'message': ('%s exception was never retrieved'
% self.__class__.__name__),
'exception': exc,
'future': self,
}
if self._source_traceback:
context['source_traceback'] = self._source_traceback
self._loop.call_exception_handler(context)
def cancel(self):
"""Cancel the future and schedule callbacks.
@ -317,13 +233,7 @@ class Future:
self._exception = exception
self._state = _FINISHED
self._schedule_callbacks()
if compat.PY34:
self._log_traceback = True
else:
self._tb_logger = _TracebackLogger(self, exception)
# Arrange for the logger to be activated after all callbacks
# have had a chance to call result() or exception().
self._loop.call_soon(self._tb_logger.activate)
self._log_traceback = True
def __iter__(self):
if not self.done():

15
Lib/asyncio/proactor_events.py
View File

@ -10,7 +10,6 @@ import socket
import warnings
from . import base_events
from . import compat
from . import constants
from . import futures
from . import sslproto
@ -86,15 +85,11 @@ class _ProactorBasePipeTransport(transports._FlowControlMixin,
self._read_fut.cancel()
self._read_fut = None
# On Python 3.3 and older, objects with a destructor part of a reference
# cycle are never destroyed. It's not more the case on Python 3.4 thanks
# to the PEP 442.
if compat.PY34:
def __del__(self):
if self._sock is not None:
warnings.warn("unclosed transport %r" % self, ResourceWarning,
source=self)
self.close()
def __del__(self):
if self._sock is not None:
warnings.warn("unclosed transport %r" % self, ResourceWarning,
source=self)
self.close()
def _fatal_error(self, exc, message='Fatal error on pipe transport'):
if isinstance(exc, base_events._FATAL_ERROR_IGNORE):

15
Lib/asyncio/selector_events.py
View File

@ -18,7 +18,6 @@ except ImportError: # pragma: no cover
ssl = None
from . import base_events
from . import compat
from . import constants
from . import events
from . import futures
@ -621,15 +620,11 @@ class _SelectorTransport(transports._FlowControlMixin,
self._loop._remove_writer(self._sock_fd)
self._loop.call_soon(self._call_connection_lost, None)
# On Python 3.3 and older, objects with a destructor part of a reference
# cycle are never destroyed. It's not more the case on Python 3.4 thanks
# to the PEP 442.
if compat.PY34:
def __del__(self):
if self._sock is not None:
warnings.warn("unclosed transport %r" % self, ResourceWarning,
source=self)
self._sock.close()
def __del__(self):
if self._sock is not None:
warnings.warn("unclosed transport %r" % self, ResourceWarning,
source=self)
self._sock.close()
def _fatal_error(self, exc, message='Fatal error on transport'):
# Should be called from exception handler only.

15
Lib/asyncio/sslproto.py
View File

@ -6,7 +6,6 @@ except ImportError: # pragma: no cover
ssl = None
from . import base_events
from . import compat
from . import protocols
from . import transports
from .log import logger
@ -325,15 +324,11 @@ class _SSLProtocolTransport(transports._FlowControlMixin,
self._closed = True
self._ssl_protocol._start_shutdown()
# On Python 3.3 and older, objects with a destructor part of a reference
# cycle are never destroyed. It's not more the case on Python 3.4 thanks
# to the PEP 442.
if compat.PY34:
def __del__(self):
if not self._closed:
warnings.warn("unclosed transport %r" % self, ResourceWarning,
source=self)
self.close()
def __del__(self):
if not self._closed:
warnings.warn("unclosed transport %r" % self, ResourceWarning,
source=self)
self.close()
def pause_reading(self):
"""Pause the receiving end.

24
Lib/asyncio/tasks.py
View File

@ -76,20 +76,16 @@ class Task(futures.Future):
self._loop.call_soon(self._step)
self.__class__._all_tasks.add(self)
# On Python 3.3 or older, objects with a destructor that are part of a
# reference cycle are never destroyed. That's not the case any more on
# Python 3.4 thanks to the PEP 442.
if compat.PY34:
def __del__(self):
if self._state == futures._PENDING and self._log_destroy_pending:
context = {
'task': self,
'message': 'Task was destroyed but it is pending!',
}
if self._source_traceback:
context['source_traceback'] = self._source_traceback
self._loop.call_exception_handler(context)
futures.Future.__del__(self)
def __del__(self):
if self._state == futures._PENDING and self._log_destroy_pending:
context = {
'task': self,
'message': 'Task was destroyed but it is pending!',
}
if self._source_traceback:
context['source_traceback'] = self._source_traceback
self._loop.call_exception_handler(context)
futures.Future.__del__(self)
def _repr_info(self):
return base_tasks._task_repr_info(self)

11
Lib/asyncio/test_utils.py
View File

@ -26,7 +26,6 @@ except ImportError: # pragma: no cover
ssl = None
from . import base_events
from . import compat
from . import events
from . import futures
from . import selectors
@ -465,16 +464,6 @@ class TestCase(unittest.TestCase):
# in an except block of a generator
self.assertEqual(sys.exc_info(), (None, None, None))
if not compat.PY34:
# Python 3.3 compatibility
def subTest(self, *args, **kwargs):
class EmptyCM:
def __enter__(self):
pass
def __exit__(self, *exc):
pass
return EmptyCM()
@contextlib.contextmanager
def disable_logger():

4
Lib/asyncio/transports.py
View File

@ -1,7 +1,5 @@
"""Abstract Transport class."""
from asyncio import compat
__all__ = ['BaseTransport', 'ReadTransport', 'WriteTransport',
'Transport', 'DatagramTransport', 'SubprocessTransport',
]
@ -104,7 +102,7 @@ class WriteTransport(BaseTransport):
The default implementation concatenates the arguments and
calls write() on the result.
"""
data = compat.flatten_list_bytes(list_of_data)
data = b''.join(list_of_data)
self.write(data)
def write_eof(self):

29
Lib/asyncio/unix_events.py
View File

@ -13,7 +13,6 @@ import warnings
from . import base_events
from . import base_subprocess
from . import compat
from . import constants
from . import coroutines
from . import events
@ -413,15 +412,11 @@ class _UnixReadPipeTransport(transports.ReadTransport):
if not self._closing:
self._close(None)
# On Python 3.3 and older, objects with a destructor part of a reference
# cycle are never destroyed. It's not more the case on Python 3.4 thanks
# to the PEP 442.
if compat.PY34:
def __del__(self):
if self._pipe is not None:
warnings.warn("unclosed transport %r" % self, ResourceWarning,
source=self)
self._pipe.close()
def __del__(self):
if self._pipe is not None:
warnings.warn("unclosed transport %r" % self, ResourceWarning,
source=self)
self._pipe.close()
def _fatal_error(self, exc, message='Fatal error on pipe transport'):
# should be called by exception handler only
@ -614,15 +609,11 @@ class _UnixWritePipeTransport(transports._FlowControlMixin,
# write_eof is all what we needed to close the write pipe
self.write_eof()
# On Python 3.3 and older, objects with a destructor part of a reference
# cycle are never destroyed. It's not more the case on Python 3.4 thanks
# to the PEP 442.
if compat.PY34:
def __del__(self):
if self._pipe is not None:
warnings.warn("unclosed transport %r" % self, ResourceWarning,
source=self)
self._pipe.close()
def __del__(self):
if self._pipe is not None:
warnings.warn("unclosed transport %r" % self, ResourceWarning,
source=self)
self._pipe.close()
def abort(self):
self._close(None)