Merge pull request #13191 from Carreau/fix-loop

Try to fix some of current failures.

.github/workflows/python-package.yml

@@ -13,6 +13,7 b' jobs:'
   build:
 
     runs-on: ubuntu-latest
+    timeout-minutes: 10
     strategy:
       matrix:
         python-version: [3.8]

.github/workflows/test.yml

@@ -45,6 +45,6 b' jobs:'
         cp /tmp/.coverage ./
     - name: pytest
       run: |
-        pytest
+        pytest -v
     - name: Upload coverage to Codecov
       uses: codecov/codecov-action@v2

IPython/core/magics/script.py

@@ -3,24 +3,23 b''
 # Copyright (c) IPython Development Team.
 # Distributed under the terms of the Modified BSD License.
 
+import asyncio
+import atexit
 import errno
+import functools
 import os
-import sys
 import signal
+import sys
 import time
-import asyncio
-import atexit
-
+from contextlib import contextmanager
 from subprocess import CalledProcessError
 
+from traitlets import Dict, List, default
+
 from IPython.core import magic_arguments
-from IPython.core.magic import  (
-    Magics, magics_class, line_magic, cell_magic
-)
+from IPython.core.magic import Magics, cell_magic, line_magic, magics_class
 from IPython.lib.backgroundjobs import BackgroundJobManager
 from IPython.utils.process import arg_split
-from traitlets import List, Dict, default
-
 
 #-----------------------------------------------------------------------------
 # Magic implementation classes
@@ -67,6 +66,41 b' def script_args(f):'
         f = arg(f)
     return f
 
+
+@contextmanager
+def safe_watcher():
+    if sys.platform == "win32":
+        yield
+        return
+
+    from asyncio import SafeChildWatcher
+
+    policy = asyncio.get_event_loop_policy()
+    old_watcher = policy.get_child_watcher()
+    if isinstance(old_watcher, SafeChildWatcher):
+        yield
+        return
+
+    loop = asyncio.get_event_loop()
+    try:
+        watcher = asyncio.SafeChildWatcher()
+        watcher.attach_loop(loop)
+        policy.set_child_watcher(watcher)
+        yield
+    finally:
+        watcher.close()
+        policy.set_child_watcher(old_watcher)
+
+
+def dec_safe_watcher(fun):
+    @functools.wraps(fun)
+    def _inner(*args, **kwargs):
+        with safe_watcher():
+            return fun(*args, **kwargs)
+
+    return _inner
+
+
 @magics_class
 class ScriptMagics(Magics):
     """Magics for talking to scripts
@@ -157,6 +191,7 b' class ScriptMagics(Magics):'
     @magic_arguments.magic_arguments()
     @script_args
     @cell_magic("script")
+    @dec_safe_watcher
     def shebang(self, line, cell):
         """Run a cell via a shell command
         
@@ -204,7 +239,6 b' class ScriptMagics(Magics):'
         if sys.platform.startswith("win"):
             asyncio.set_event_loop_policy(asyncio.WindowsProactorEventLoopPolicy())
         loop = asyncio.get_event_loop()
-
         argv = arg_split(line, posix=not sys.platform.startswith("win"))
         args, cmd = self.shebang.parser.parse_known_args(argv)
         try:

IPython/core/tests/test_magic.py

@@ -4,38 +4,42 b''
 Needs to be run by nose (to make ipython session available).
 """
 
+import asyncio
 import io
 import os
 import re
+import shlex
 import sys
 import warnings
-from textwrap import dedent
-from unittest import TestCase
-from unittest import mock
 from importlib import invalidate_caches
 from io import StringIO
 from pathlib import Path
+from textwrap import dedent
+from unittest import TestCase, mock
 
 import nose.tools as nt
 
-import shlex
+import pytest
 
 from IPython import get_ipython
 from IPython.core import magic
 from IPython.core.error import UsageError
-from IPython.core.magic import (Magics, magics_class, line_magic,
-                                cell_magic,
-                                register_line_magic, register_cell_magic)
-from IPython.core.magics import execution, script, code, logging, osm
+from IPython.core.magic import (
+    Magics,
+    cell_magic,
+    line_magic,
+    magics_class,
+    register_cell_magic,
+    register_line_magic,
+)
+from IPython.core.magics import code, execution, logging, osm, script
 from IPython.testing import decorators as dec
 from IPython.testing import tools as tt
 from IPython.utils.io import capture_output
-from IPython.utils.tempdir import (TemporaryDirectory,
-                                    TemporaryWorkingDirectory)
 from IPython.utils.process import find_cmd
-from .test_debugger import PdbTestInput
+from IPython.utils.tempdir import TemporaryDirectory, TemporaryWorkingDirectory
 
-import pytest
+from .test_debugger import PdbTestInput
 
 
 @magic.magics_class
@@ -947,33 +951,64 b' def test_script_config():'
     sm = script.ScriptMagics(shell=ip)
     nt.assert_in('whoda', sm.magics['cell'])
 
[e-mail]_iptest_but_not_pytest
 @dec.skip_win32
[e-mail](
+    sys.platform == "win32", reason="This test does not run under Windows"
+)
 def test_script_out():
+    assert asyncio.get_event_loop().is_running() is False
+
     ip = get_ipython()
     ip.run_cell_magic("script", "--out output sh", "echo 'hi'")
+    assert asyncio.get_event_loop().is_running() is False
     nt.assert_equal(ip.user_ns['output'], 'hi\n')
 
[e-mail]_iptest_but_not_pytest
 @dec.skip_win32
[e-mail](
+    sys.platform == "win32", reason="This test does not run under Windows"
+)
 def test_script_err():
     ip = get_ipython()
+    assert asyncio.get_event_loop().is_running() is False
     ip.run_cell_magic("script", "--err error sh", "echo 'hello' >&2")
+    assert asyncio.get_event_loop().is_running() is False
     nt.assert_equal(ip.user_ns['error'], 'hello\n')
 
+
[e-mail]_iptest_but_not_pytest
 @dec.skip_win32
[e-mail](
+    sys.platform == "win32", reason="This test does not run under Windows"
+)
 def test_script_out_err():
+
     ip = get_ipython()
-    ip.run_cell_magic("script", "--out output --err error sh", "echo 'hi'\necho 'hello' >&2")
-    nt.assert_equal(ip.user_ns['output'], 'hi\n')
-    nt.assert_equal(ip.user_ns['error'], 'hello\n')
+    ip.run_cell_magic(
+        "script", "--out output --err error sh", "echo 'hi'\necho 'hello' >&2"
+    )
+    nt.assert_equal(ip.user_ns["output"], "hi\n")
+    nt.assert_equal(ip.user_ns["error"], "hello\n")
 
+
[e-mail]_iptest_but_not_pytest
 @dec.skip_win32
[e-mail](
+    sys.platform == "win32", reason="This test does not run under Windows"
+)
 async def test_script_bg_out():
     ip = get_ipython()
     ip.run_cell_magic("script", "--bg --out output sh", "echo 'hi'")
     nt.assert_equal((await ip.user_ns["output"].read()), b"hi\n")
-    ip.user_ns['output'].close()
+    ip.user_ns["output"].close()
+    asyncio.get_event_loop().stop()
 
[e-mail]_iptest_but_not_pytest
 @dec.skip_win32
[e-mail](
+    sys.platform == "win32", reason="This test does not run under Windows"
+)
 async def test_script_bg_err():
     ip = get_ipython()
     ip.run_cell_magic("script", "--bg --err error sh", "echo 'hello' >&2")
@@ -981,7 +1016,11 b' async def test_script_bg_err():'
     ip.user_ns["error"].close()
 
 
[e-mail]_iptest_but_not_pytest
 @dec.skip_win32
[e-mail](
+    sys.platform == "win32", reason="This test does not run under Windows"
+)
 async def test_script_bg_out_err():
     ip = get_ipython()
     ip.run_cell_magic(