Negative idle time when using a time-zone different from host machine

[AnezeR]

local python version: 3.9.16
docker python: python:3.9-slim-buster

schedule==1.2.0
pytz==2023.3

I have this code, which I run inside a docker container

schedule.every().day.at('07:00', 'Europe/Moscow').do(send_practice_notifications)
schedule.every().day.at('20:00', 'Europe/Moscow').do(send_practice_notifications)

while True:
    n = schedule.idle_seconds()
    print(n)
    if n is None:
        break
    elif n < 0:
        time.sleep(1)
        continue
    elif n > 0:
        time.sleep(n)
    schedule.run_pending()

In this case it outputs negative time and would attempt to run send_practice_notifications, which I want to happen only at specified time, and not every time the program starts.

-7848.127428
-7849.128611
-7850.129724
-7851.130872
-7852.132034
-7853.133061

When run natively, however, it outputs a positive expected value and does not run any functions.
30777.206617
I think this is an error related to time-zones because docker container uses UTC time, and running natively puts it in the Europe/Moscow timezone.
Sure enough, changing the code in docker to

###

schedule.every().day.at('07:00').do(send_practice_notifications)
schedule.every().day.at('20:00').do(send_practice_notifications)

###

Makes the output positive and expected
1709.825228

[AnezeR]

I think the issue is in this block

schedule/schedule/__init__.py

Lines 752 to 771 in a3c2074

	if self.at_time_zone is not None:
	# Convert next_run from the expected timezone into the local time
	# self.next_run is a naive datetime so after conversion remove tzinfo
	self.next_run = (
	self.at_time_zone.localize(self.next_run)
	.astimezone()
	.replace(tzinfo=None)
	)
	# Make sure we run at the specified time *today* (or *this hour*)
	# as well. This accounts for when a job takes so long it finished
	# in the next period.
	if not self.last_run or (self.next_run - self.last_run) > self.period:
	now = datetime.datetime.now()
	if (
	self.unit == "days"
	and self.at_time > now.time()
	and self.interval == 1
	):
	self.next_run = self.next_run - datetime.timedelta(days=1)

It subtracts one day if self.at_time is greater than now():

schedule/schedule/__init__.py

Line 768 in a3c2074

and self.at_time > now.time()

But, since self.at_time is not updated in

schedule/schedule/__init__.py

Lines 752 to 759 in a3c2074

	if self.at_time_zone is not None:
	# Convert next_run from the expected timezone into the local time
	# self.next_run is a naive datetime so after conversion remove tzinfo
	self.next_run = (
	self.at_time_zone.localize(self.next_run)
	.astimezone()
	.replace(tzinfo=None)
	)

It still executes.
E.G.
If the machine uses UTC time and execution time is 20:00 in UTC+3, self.next_run would change to 17:00 UTC, while self.at_time would stay at 20:00.
Now, if the machine time is 19:00 UTC, it should not subtract a day, since it is already 2 hours past execution time, but, it would see, that 19:00 is less than 20:00 and subtract a day from self.next_run

[SijmenHuizenga]

Thank you so much for investigating and creating a pr! #583 has been merged and released in 1.2.1