+[__NSCFConstantString initialize] may have been in progress in another thread when fork() was called.

[Ebrahimhammad]

Hi all,

issue is below:

objc[8104]: +[__NSCFConstantString initialize] may have been in progress in another thread when fork() was called.
objc[8104]: +[__NSCFConstantString initialize] may have been in progress in another thread when fork() was called. We cannot safely call it or ignore it in the fork() child process. Crashing instead. Set a breakpoint on objc_initializeAfterForkError to debug.
14:35:46 Moving job to FailedJobRegistry (work-horse terminated unexpectedly; waitpid returned 6)

After a little research, it seems specifically related to macOS. I am using it on production on Ubuntu server and it is working fine.

But on my local machine, macOS, this error showing up.

.. now this error is showing when I am trying to send a message through Twilio.

I am not sure now if this caused by Twilio or Django-rq ?

Thank you

[poitch]

I'm seeing the same issue on MacOS 12.4
% python --version
Python 3.10.5

I am not using Twilio.

I have had this issue on MacOS since 2020 personally and was never able to use django-rq for my local development environment.

[selwin]

@poitch can you try to reproduce this locally and send a few stack traces? Also, does Django RQ's test suite runs on your local development environment?

[selwin]

This issue may be related to #375 @poitch @Ebrahimhammad . Have you tried changing the worker class to SimpleWorker (does not call os.fork()) and see if it works?

[a-toms]

Had the same problem on M1 mac.

Fix: Set an env var in your terminal.
export OBJC_DISABLE_INITIALIZE_FORK_SAFETY=YES

Description: rails/rails#38560 (comment)

[adamghill]

Have you tried changing the worker class to SimpleWorker (does not call os.fork()) and see if it works?

I have the same issue as the OP on my M1 Mac. I tried to using SimpleWorker with this in my settings:

RQ = {"WORKER_CLASS": "rq.SimpleWorker"}

That prevented the error from happening.

Running the worker with OBJC_DISABLE_INITIALIZE_FORK_SAFETY=YES python manage.py rqworker also seems to work.

[ramsondon]

OBJC_DISABLE_INITIALIZE_FORK_SAFETY=YESfixed the problem for python.3.11 django 4.2.11, celery 5.3.4

when trying to start a delayed shared_task from a management command by another terminal process