I noticed this while checking bpo-35961. test_venv is always failing on GCC which is marked as optional in Travis.

Log : https://travis-ci.org/python/cpython/jobs/492123436#L1909

0:39:35 load avg: 1.00 [390/416] test_venv
test test_venv failed -- Traceback (most recent call last):
  File "/home/travis/build/python/cpython/Lib/test/test_venv.py", line 309, in test_multiprocessing
    out, err = check_output([envpy, '-c',
  File "/home/travis/build/python/cpython/Lib/test/test_venv.py", line 37, in check_output
    raise subprocess.CalledProcessError(
subprocess.CalledProcessError: Command '['/tmp/tmpg8ubeyfn/bin/python', '-c', 'from multiprocessing import Pool; print(Pool(1).apply_async("Python".lower).get(3))']' died with <Signals.SIGABRT: 6>.

Also GCC test have been timing out for at least past 4 months : https://python.zulipchat.com/#narrow/stream/116742-core.2Fhelp/topic/GCC.20build.20in.20Travis.20always.20times.20out

Pablo: Can this issue be related bpo-35378?

commit 3766f18
Author: Pablo Galindo <Pablogsal@gmail.com>
Date: Mon Feb 11 17:29:00 2019 +0000

bpo-35378: Fix multiprocessing.Pool references (GH-11627)

That looks like a similar example of the problem that bpo-35378 solves. But the PR is merged and the test keeps failing:

test test_venv failed -- Traceback (most recent call last):
  File "/home/travis/build/python/cpython/Lib/test/test_venv.py", line 309, in test_multiprocessing
    out, err = check_output([envpy, '-c',
  File "/home/travis/build/python/cpython/Lib/test/test_venv.py", line 37, in check_output
    raise subprocess.CalledProcessError(
subprocess.CalledProcessError: Command '['/tmp/tmplplx90pf/bin/python', '-c', 'from multiprocessing import Pool; print(Pool(1).apply_async("Python".lower).get(3))']' died with <Signals.SIGABRT: 6>.

https://travis-ci.org/python/cpython/jobs/492305033

Running that command locally on master does not die with SIGABRT:

❯ ./python -c 'from multiprocessing import Pool; print(Pool(1).apply_async("Python".lower).get(3))'; echo $?
python
/home/pablogsal/github/cpython/Lib/multiprocessing/pool.py:234: ResourceWarning: unclosed running multiprocessing pool <multiprocessing.pool.Pool state=RUN pool_size=1>
_warn(f"unclosed running multiprocessing pool {self!r}",
ResourceWarning: Enable tracemalloc to get the object allocation traceback
0

I can reproduce the crash using the same command than the job.

Simplified commands to reproduce the bug:

./configure && make
./python -m venv venv
./venv/bin/python -m test test_venv -m test.test_venv.BasicTest.test_multiprocessing

The Python of the virtual environment created by the test doesn't work:

$ /tmp/tmp0vybyos2/bin/python -c pass
Could not find platform independent libraries <prefix>
Could not find platform dependent libraries <exec_prefix>
Consider setting $PYTHONHOME to <prefix>[:<exec_prefix>]
Fatal Python error: initfsencoding: failed to get the Python codec of the filesystem encoding
ModuleNotFoundError: No module named 'encodings'

Current thread 0x00007f2956ab8740 (most recent call first):
Aborted

Hum, test_executable() of test_venv is skipped if run in a venv, but not test_multiprocessing():

# If a venv is created from a source build and that venv is used to
# run the test, the pyvenv.cfg in the venv created in the test will
# point to the venv being used to run the test, and we lose the link
# to the source build - so Python can't initialise properly.
@skipInVenv
    ...
    self.run_with_capture(venv.create, self.env_dir)
    envpy = os.path.join(os.path.realpath(self.env_dir),
                         self.bindir, self.exe)
    ...

    def test_multiprocessing(self):
        ...
        self.run_with_capture(venv.create, self.env_dir)
        envpy = os.path.join(os.path.realpath(self.env_dir),
                             self.bindir, self.exe)
        ...

The test has been added by:

commit 4e02f8f
Author: Steve Dower <steve.dower@microsoft.com>
Date: Fri Jan 25 14:59:12 2019 -0800

I guess we need a "skipInLinuxVenv", since it works fine on Windows :)

I'm on this. I'll make a new (or possibly complete replacement) for @skipInVenv that is @requireVenvCreate, since that's the common piece that doesn't work in a venv (except on Windows).

New changeset 8bba81f by Steve Dower in branch 'master':
bpo-35978: Correctly skips venv tests in venvs (GH-12220)
8bba81f

New changeset b0967fe by Miss Islington (bot) in branch '3.7':
bpo-35978: Correctly skips venv tests in venvs (GH-12220)
b0967fe