Cannot run pylint with multiple processes (Termux)

[harshil21]

Bug description

I cannot run pylint with the argument -j 0 since my platform (Android - Termux) says that it cannot import SemLock.

Configuration

No response

Command used

pylint test.py -j 0

Pylint output

Traceback (most recent call last):
  File "/data/data/com.termux/files/usr/lib/python3.9/multiprocessing/synchronize.py", line 28, in <module>
    from _multiprocessing import SemLock, sem_unlink
ImportError: cannot import name 'SemLock' from '_multiprocessing' (/data/data/com.termux/files/usr/lib/python3.9/lib-dynload/_multiprocessing.cpython-39.so)

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/data/data/com.termux/files/usr/bin/pylint", line 8, in <module>
    sys.exit(run_pylint())
  File "/data/data/com.termux/files/usr/lib/python3.9/site-packages/pylint/__init__.py", line 24, in run_pylint
    PylintRun(sys.argv[1:])
  File "/data/data/com.termux/files/usr/lib/python3.9/site-packages/pylint/lint/run.py", line 374, in init
    linter.check(args)
  File "/data/data/com.termux/files/usr/lib/python3.9/site-packages/pylint/lint/pylinter.py", line 974, in check
    check_parallel(
  File "/data/data/com.termux/files/usr/lib/python3.9/site-packages/pylint/lint/parallel.py", line 132, in check_parallel
    pool = multiprocessing.Pool(  # pylint: disable=consider-using-with
  File "/data/data/com.termux/files/usr/lib/python3.9/multiprocessing/context.py", line 119, in Pool
    return Pool(processes, initializer, initargs, maxtasksperchild,
  File "/data/data/com.termux/files/usr/lib/python3.9/multiprocessing/pool.py", line 191, in init
    self._setup_queues()
  File "/data/data/com.termux/files/usr/lib/python3.9/multiprocessing/pool.py", line 343, in _setup_queues
    self._inqueue = self._ctx.SimpleQueue()
  File "/data/data/com.termux/files/usr/lib/python3.9/multiprocessing/context.py", line 113, in SimpleQueue
    return SimpleQueue(ctx=self.get_context())
  File "/data/data/com.termux/files/usr/lib/python3.9/multiprocessing/queues.py", line 342, in init
    self._rlock = ctx.Lock()
  File "/data/data/com.termux/files/usr/lib/python3.9/multiprocessing/context.py", line 67, in Lock
    from .synchronize import Lock
  File "/data/data/com.termux/files/usr/lib/python3.9/multiprocessing/synchronize.py", line 30, in <module>
    raise ImportError("This platform lacks a functioning sem_open" +
ImportError: This platform lacks a functioning sem_open implementation, therefore, the required synchronization primitives needed will not function, see issue 3770.

Expected behavior

Pylint should gracefully ignore the -j option if there is an error importing the above.

Pylint version

pylint 2.11.1
astroid 2.8.4
Python 3.9.6 (default, Aug  1 2021, 15:58:14)
[Clang 9.0.8 (https://android.googlesource.com/toolchain/llvm-project 98c855489

OS / Environment

Android 10, Termux

Additional dependencies

No response

[Pierre-Sassoulas]

Thank you for opening the issue, indeed you're right.