[Python-checkins] [3.6] bpo-32356: idempotent pause_/resume_reading (GH-4914) (GH-7629)

Wed Jun 13 06:05:19 EDT 2018

https://github.com/python/cpython/commit/142e3c08a40c75b5788474b0defe7d5c0671f675
commit: 142e3c08a40c75b5788474b0defe7d5c0671f675
branch: 3.6
author: Victor Stinner <vstinner at redhat.com>
committer: GitHub <noreply at github.com>
date: 2018年06月13日T12:05:15+02:00
summary:
[3.6] bpo-32356: idempotent pause_/resume_reading (GH-4914) (GH-7629)
Backport note: don't add new is_reading() method from master to 3.6.
(cherry picked from commit d757aaf9dd767d13205bf9917e520ebf43e7f6e5)
files:
A Misc/NEWS.d/next/Library/2017-12-17-22-50-51.bpo-32356.roZJpA.rst
M Doc/library/asyncio-protocol.rst
M Lib/asyncio/proactor_events.py
M Lib/asyncio/selector_events.py
M Lib/asyncio/test_utils.py
M Lib/test/test_asyncio/test_proactor_events.py
M Lib/test/test_asyncio/test_selector_events.py

diff --git a/Doc/library/asyncio-protocol.rst b/Doc/library/asyncio-protocol.rst
index cd84ae76b5d8..9605261c0a3f 100644
--- a/Doc/library/asyncio-protocol.rst
+++ b/Doc/library/asyncio-protocol.rst
@@ -124,11 +124,19 @@ ReadTransport
 the protocol's :meth:`data_received` method until :meth:`resume_reading`
 is called.
 
+ .. versionchanged:: 3.6.7
+ The method is idempotent, i.e. it can be called when the
+ transport is already paused or closed.
+
 .. method:: resume_reading()
 
 Resume the receiving end. The protocol's :meth:`data_received` method
 will be called once again if some data is available for reading.
 
+ .. versionchanged:: 3.6.7
+ The method is idempotent, i.e. it can be called when the
+ transport is already reading.
+
 
 WriteTransport
 --------------
diff --git a/Lib/asyncio/proactor_events.py b/Lib/asyncio/proactor_events.py
index 967a696961a6..6f621ef0cc4f 100644
--- a/Lib/asyncio/proactor_events.py
+++ b/Lib/asyncio/proactor_events.py
@@ -160,20 +160,16 @@ def __init__(self, loop, sock, protocol, waiter=None,
 self._loop.call_soon(self._loop_reading)
 
 def pause_reading(self):
- if self._closing:
- raise RuntimeError('Cannot pause_reading() when closing')
- if self._paused:
- raise RuntimeError('Already paused')
+ if self._closing or self._paused:
+ return
 self._paused = True
 if self._loop.get_debug():
 logger.debug("%r pauses reading", self)
 
 def resume_reading(self):
- if not self._paused:
- raise RuntimeError('Not paused')
- self._paused = False
- if self._closing:
+ if self._closing or not self._paused:
 return
+ self._paused = False
 if self._reschedule_on_resume:
 self._loop.call_soon(self._loop_reading, self._read_fut)
 self._reschedule_on_resume = False
diff --git a/Lib/asyncio/selector_events.py b/Lib/asyncio/selector_events.py
index 81dfd7651c5e..bc7c740cc2af 100644
--- a/Lib/asyncio/selector_events.py
+++ b/Lib/asyncio/selector_events.py
@@ -703,18 +703,16 @@ def __init__(self, loop, sock, protocol, waiter=None,
 waiter, None)
 
 def pause_reading(self):
- if self._closing:
- raise RuntimeError('Cannot pause_reading() when closing')
- if self._paused:
- raise RuntimeError('Already paused')
+ if self._closing or self._paused:
+ return
 self._paused = True
 self._loop._remove_reader(self._sock_fd)
 if self._loop.get_debug():
 logger.debug("%r pauses reading", self)
 
 def resume_reading(self):
- if not self._paused:
- raise RuntimeError('Not paused')
+ if self._closing or not self._paused:
+ return
 self._paused = False
 self._add_reader(self._sock_fd, self._read_ready)
 if self._loop.get_debug():
diff --git a/Lib/asyncio/test_utils.py b/Lib/asyncio/test_utils.py
index 8b8c22a74757..f41720428cec 100644
--- a/Lib/asyncio/test_utils.py
+++ b/Lib/asyncio/test_utils.py
@@ -335,12 +335,19 @@ def _remove_reader(self, fd):
 return False
 
 def assert_reader(self, fd, callback, *args):
- assert fd in self.readers, 'fd {} is not registered'.format(fd)
+ if fd not in self.readers:
+ raise AssertionError(f'fd {fd} is not registered')
 handle = self.readers[fd]
- assert handle._callback == callback, '{!r} != {!r}'.format(
- handle._callback, callback)
- assert handle._args == args, '{!r} != {!r}'.format(
- handle._args, args)
+ if handle._callback != callback:
+ raise AssertionError(
+ f'unexpected callback: {handle._callback} != {callback}')
+ if handle._args != args:
+ raise AssertionError(
+ f'unexpected callback args: {handle._args} != {args}')
+
+ def assert_no_reader(self, fd):
+ if fd in self.readers:
+ raise AssertionError(f'fd {fd} is registered')
 
 def _add_writer(self, fd, callback, *args):
 self.writers[fd] = events.Handle(callback, args, self)
diff --git a/Lib/test/test_asyncio/test_proactor_events.py b/Lib/test/test_asyncio/test_proactor_events.py
index edf0461957f8..ba187c97fed4 100644
--- a/Lib/test/test_asyncio/test_proactor_events.py
+++ b/Lib/test/test_asyncio/test_proactor_events.py
@@ -334,6 +334,7 @@ def test_pause_resume_reading(self):
 f = asyncio.Future(loop=self.loop)
 f.set_result(msg)
 futures.append(f)
+
 self.loop._proactor.recv.side_effect = futures
 self.loop._run_once()
 self.assertFalse(tr._paused)
@@ -341,11 +342,15 @@ def test_pause_resume_reading(self):
 self.protocol.data_received.assert_called_with(b'data1')
 self.loop._run_once()
 self.protocol.data_received.assert_called_with(b'data2')
+
+ tr.pause_reading()
 tr.pause_reading()
 self.assertTrue(tr._paused)
 for i in range(10):
 self.loop._run_once()
 self.protocol.data_received.assert_called_with(b'data2')
+
+ tr.resume_reading()
 tr.resume_reading()
 self.assertFalse(tr._paused)
 self.loop._run_once()
diff --git a/Lib/test/test_asyncio/test_selector_events.py b/Lib/test/test_asyncio/test_selector_events.py
index c359b458029d..533d2898e7fc 100644
--- a/Lib/test/test_asyncio/test_selector_events.py
+++ b/Lib/test/test_asyncio/test_selector_events.py
@@ -81,6 +81,7 @@ def test_make_ssl_transport(self):
 with test_utils.disable_logger():
 transport = self.loop._make_ssl_transport(
 m, asyncio.Protocol(), m, waiter)
+
 # execute the handshake while the logger is disabled
 # to ignore SSL handshake failure
 test_utils.run_briefly(self.loop)
@@ -884,14 +885,19 @@ def test_pause_resume_reading(self):
 test_utils.run_briefly(self.loop)
 self.assertFalse(tr._paused)
 self.loop.assert_reader(7, tr._read_ready)
+
+ tr.pause_reading()
 tr.pause_reading()
 self.assertTrue(tr._paused)
- self.assertFalse(7 in self.loop.readers)
+ self.loop.assert_no_reader(7)
+
+ tr.resume_reading()
 tr.resume_reading()
 self.assertFalse(tr._paused)
 self.loop.assert_reader(7, tr._read_ready)
- with self.assertRaises(RuntimeError):
- tr.resume_reading()
+
+ tr.close()
+ self.loop.assert_no_reader(7)
 
 def test_read_ready(self):
 transport = self.socket_transport()
diff --git a/Misc/NEWS.d/next/Library/2017-12-17-22-50-51.bpo-32356.roZJpA.rst b/Misc/NEWS.d/next/Library/2017-12-17-22-50-51.bpo-32356.roZJpA.rst
new file mode 100644
index 000000000000..95a71de4ce8e
--- /dev/null
+++ b/Misc/NEWS.d/next/Library/2017-12-17-22-50-51.bpo-32356.roZJpA.rst
@@ -0,0 +1 @@
+asyncio.transport.resume_reading() and pause_reading() are now idempotent.
