Confirm that 4.x won't require tzlocal

[davetapley]

Can someone confirm that upcoming 4.x won't require tzlocal any more?

It's tangentially mentioned in the v3.x to v4.0 docs here:

apscheduler/docs/migration.rst

Lines 89 to 93 in 77a8002

	As the scheduler is no longer used to create triggers, any supplied datetimes will be
	assumed to be in the local time zone. If you wish to change the local time zone, you
	should set the ``TZ`` environment variable to either the name of the desired timezone
	(e.g. ``Europe/Helsinki``) or to a path of a time zone file. See the tzlocal_
	documentation for more information.

---

I ask because TIL 3.x requires tzlocal, which requires tzdata, which comprises 603 files.

That is nearly half the files in my app when built with PyInstaller, doubling the time it takes to extract, despite my app being Python 3.11 and so already having the zoneinfo builtin with all the zones 🤪

I was going to look for a way to mitigate including all of tzdata's files, but if 4.x removes the dependency then I'll just wait 🤞🏻

[agronholm]

How would APScheduler get the local timezone then?

[davetapley]

I think datetime.astimezone(None)?

If called without arguments (or with tz=None) the system local timezone is assumed for the target timezone.

https://docs.python.org/3.11/library/datetime.html#datetime.datetime.astimezone

---

To be sure: I have no knowledge of internals of APScheduler (or why it needed tzlocal in the first place) 😁

[agronholm]

Unfortunately that uses a datetime.timezone object which is just a fixed UTC offset, so daylight saving time calculations won't work right.