During the execution process of scheduled tasks, a change in the system time can result in incorrect execution timing.

[ssongliu]

Hello @robfig.

Thank you very much for providing such excellent code! but I have encountered an issue while using it.

Suppose the current time is 2023-11-02 09:00:00, and I've enabled a scheduled task to run at 10:30 every day.
(Based on the code and the current time, a 1-hour timer will be activated.)

for {
		// Determine the next entry to run.
		sort.Sort(byTime(c.entries))

		var timer *time.Timer
		if len(c.entries) == 0 || c.entries[0].Next.IsZero() {
			// If there are no entries yet, just sleep - it still handles new entries
			// and stop requests.
			timer = time.NewTimer(100000 * time.Hour)
		} else {
			timer = time.NewTimer(c.entries[0].Next.Sub(now))
		}
...

Change the system time to 2023-11-05 06:00:00.
(When the timer runs one hour later, it starts execution, and at that time, the system time is 2023-11-05 07:00:00.) At this point, the execution condition only relies on the following code:

if e.Next.After(now) || e.Next.IsZero() {
    break
}

It will pass this condition and execute the scheduled task without matching the originally set execution time of 10:30.

Thanks.

[jiangzhongqiang]

Hello @robfig.

Thank you very much for providing such excellent code! but I have encountered an issue while using it.

Suppose the current time is 2023-11-02 09:00:00, and I've enabled a scheduled task to run at 10:30 every day. (Based on the code and the current time, a 1-hour timer will be activated.)

for {
		// Determine the next entry to run.
		sort.Sort(byTime(c.entries))

		var timer *time.Timer
		if len(c.entries) == 0 || c.entries[0].Next.IsZero() {
			// If there are no entries yet, just sleep - it still handles new entries
			// and stop requests.
			timer = time.NewTimer(100000 * time.Hour)
		} else {
			timer = time.NewTimer(c.entries[0].Next.Sub(now))
		}
...

Change the system time to 2023-11-05 06:00:00. (When the timer runs one hour later, it starts execution, and at that time, the system time is 2023-11-05 07:00:00.) At this point, the execution condition only relies on the following code:

if e.Next.After(now) || e.Next.IsZero() {
    break
}

It will pass this condition and execute the scheduled task without matching the originally set execution time of 10:30.

Thanks.

系统时间都改了，这种表现是正常的啊，我觉得没啥问题

[elbert-chan]

Hello @robfig.

Thank you very much for providing such excellent code! but I have encountered an issue while using it.

Suppose the current time is 2023-11-02 09:00:00, and I've enabled a scheduled task to run at 10:30 every day. (Based on the code and the current time, a 1-hour timer will be activated.)

for {
		// Determine the next entry to run.
		sort.Sort(byTime(c.entries))

		var timer *time.Timer
		if len(c.entries) == 0 || c.entries[0].Next.IsZero() {
			// If there are no entries yet, just sleep - it still handles new entries
			// and stop requests.
			timer = time.NewTimer(100000 * time.Hour)
		} else {
			timer = time.NewTimer(c.entries[0].Next.Sub(now))
		}
...

Change the system time to 2023-11-05 06:00:00. (When the timer runs one hour later, it starts execution, and at that time, the system time is 2023-11-05 07:00:00.) At this point, the execution condition only relies on the following code:

if e.Next.After(now) || e.Next.IsZero() {
    break
}

It will pass this condition and execute the scheduled task without matching the originally set execution time of 10:30.

Thanks.

This doesn't seem to be a problem for this library to deal with. The issues should be closed.