[BUG] CronTrigger may fire multiple times at once

[mifuyutsuki]

Library Version

5.13.1

Describe the Bug

On some occasions, a Task using CronTrigger would fire multiple times "at once". As illustrated by my bot log while developing a feature, for cron * * * * *, i.e. minutely:

2024-07-15 22:50:00,002 [INFO] mitsuki.modules.schedule.daemon:60: Fired schedule 'Daily Questions'
2024-07-15 22:51:00,025 [INFO] mitsuki.modules.schedule.daemon:60: Fired schedule 'Daily Questions'
2024-07-15 22:51:59,996 [INFO] mitsuki.modules.schedule.daemon:60: Fired schedule 'Daily Questions'
2024-07-15 22:51:59,999 [INFO] mitsuki.modules.schedule.daemon:60: Fired schedule 'Daily Questions'
2024-07-15 22:52:00,001 [INFO] mitsuki.modules.schedule.daemon:60: Fired schedule 'Daily Questions'

Note the latter three fires occuring mere miliseconds apart instead of about 60 seconds, and the "duplicated" fires all happening miliseconds earlier than it should be.

Investigation showed that CronTrigger used datetime.now() to find the next fire time, which can cause issues when now() is less than the previously set next fire time, hence the issue. Let's imagine an hourly cron task (0 * * * *):

Action	Normal	Bug
Task start	23:59:31,000	23:59:31,000
Next fire	00:00:00,000	00:00:00,000
Task fire	00:00:00,005	23:59:59,995
Next fire	01:00:00,000	00:00:00,000

In summary, if for some reason the task fires moments before the supposed firing time of XX:00:00,000, CronTrigger's next firing time would fail to advance as it should due to using now() as reference time. This manifests in the task firing multiple times "at once".

Steps to Reproduce

Create and start a interactions.py Task using trigger CronTrigger.

For illustration purposes, the cron in use is * * * * * (every minute when the second ticks zero) and the task just prints the current time.

Expected Results

Task fires once every minute (or as specified by cron) and not more at once.

With said example task, this is shown by the printed current time being always about 60 seconds after the previous.

Minimal Reproducible Code

from interactions import Client, Intents, Task, listen, CronTrigger
from datetime import datetime
bot = Client(intents=Intents.DEFAULT)

@listen()
async def on_startup():
  test_task.start()

@Task.create(CronTrigger("* * * * *"))
async def test_task():
  print(datetime.now().isoformat())

bot.start("token")

Traceback

No response

Checklist

• I have searched the open issues for duplicates.
• I have shown the entire traceback, if possible.
• I have removed my token from display, if visible.
• I have attempted to debug this myself, and I believe this issue is with the library

Additional Information

A pull request is being made to fix this issue.