How do you debug a Python script that crashes Python itself?

TL;DR

Use faulthandler.enable(); Python will print the stack trace to stderr before fully crashing.

Backstory

Today I tried to daemonize a Python script that calls request.get on macOS, and it was insta-dying for no apparent reason.

I tested without daemonization, but the problem only popped up when I daemonize it.

I was doing something like this:

from daemon import DaemonContext
from daemon.pidfile import PIDLockFile
import requests
import time


pid = PIDLockFile(path.join(home_dir, 'pidfile_watcher' …

debug macos python python script stack