Jobs deleted when modifying if ProcessPoolExecuter is default executer

[alenzo-pinc]

Things to check first

• I have checked that my issue does not already have a solution in the FAQ

• I have searched the existing issues and didn't find my bug already reported there

• I have checked that my bug is still present in the latest release

Version

3.9.1

What happened?

When calling BackgroundScheduler.modify_job() when a ProcessPoolExecuter has been set as the default, jobs are removed from the job-store after entering the _jobstores_lock context manager on line 486. This results in a job not found exception.

We have just migrated from a ThreadPoolExecuter and our tests started failing. Found this issue in vscode debugger. Issue is resolved when ThreadPoolExecuter is set as defualt.

setup:

        executors = {
            "default": ProcessPoolExecutor(max_workers=scheduler_settings.workers),
            # "default": ThreadPoolExecutor(max_workers=scheduler_settings.workers),
        }
        self.sched = BackgroundScheduler(executors=executors)

debug output:

How can we reproduce the bug?

Set default executer to ProcessPoolExecuter and modify a job which exists in the default job store.

from datetime import datetime
from unittest.mock import MagicMock

from apscheduler.executors.pool import ProcessPoolExecutor, ThreadPoolExecutor
from apscheduler.schedulers.background import BackgroundScheduler

executors = {
    "default": ProcessPoolExecutor(max_workers=10),  # THIS DOESN'T WORK
    # "default": ThreadPoolExecutor(max_workers=scheduler_settings.workers), # THIS WORKS
}

sched = BackgroundScheduler(executors=executors)
sched.start()


sched.add_job(print, args=["hi"], id="test")
sched.modify_job("test", next_run_time=datetime.now())  # This throws JobLookupError