range(): step exceeds the specified range

[pjebs]

@dragonmantank
I'm using v2 of library:

$now = new Carbon();
$cron = CronExpression::factory("41-59/24 5 * * 5");
for ($k = 0 ; $k < 20; $k++){
	$t = $cron->getNextRunDate($now, $k);
	$times[] = $t; // Store next 20 values
}
		

Error:

range(): step exceeds the specified range

/vendor/dragonmantank/cron-expression/src/Cron/AbstractField.php:148
/vendor/dragonmantank/cron-expression/src/Cron/AbstractField.php:53
/vendor/dragonmantank/cron-expression/src/Cron/MinutesField.php:31
/vendor/dragonmantank/cron-expression/src/Cron/CronExpression.php:362
/vendor/dragonmantank/cron-expression/src/Cron/CronExpression.php:199

[pjebs]

51-59/57 14 * * 0,1,2,3,4,5,6 also generates the same error.

12-17/43 17 * * 1,3,4,5,6

[pjebs]

In PHP 8, this range($rangeStart, $rangeEnd, $step) in AbstractField.php will return a catchable ValueError.

Until then, it needs to handled in the code.

[pjebs]

Obviously the cron string is nonsensical - but still valid so it should not throw an error.

[dragonmantank]

Obviously the cron string is nonsensical - but still valid

Within the bounds of this library, it's invalid. What happens with a step larger than the range is ambiguous - does it wrap around, does it only run the first, does it truncate? Some libraries handle it, some do not.

This would be the intended error. Your intended step is too large, and will not function, so the error is thrown. It's better to have the error letting you know the cron is invalid than let it "run" with unintended results.

[dragonmantank]

Reopening, because 2 years ago I validated the cronie allowed wrap-around steps. Since this library follows cronie, the larger step should wrap around to the beginning and continue counting.

This looks like a break between validation and when we do the stepping on small ranges versus *, so will get that corrected.

[dragonmantank]

Sorry this took so long. It's actually a few different subtle issues that dealt wit "how much can break."

So, cronie supports steps larger than a range, but it doesn't actually wrap around. Internally it's using a for() loop so large steps never actually affect the validation, where PHP's range() method has some checks built in.

This library does have, incorrectly, some logic to handle wrapping around. That will be going away. I fixed this particular bug with the correct behavior, so if you specify a range that is smaller than max, but a step that is larger than the small range, you will only ever match against the first value in the range. So given 41-59/24, you will only match minute 41, not 41 + 47 (if I did the wraparound math right).

So given a run date of 2021-08-25 10:00:00, your next run dates are:

• 2021-08-26 05:41:00
• 2021-08-27 05:41:00
• 2021-08-28 05:41:00

This is fixed in master, I will update and close the ticket once I cut a release.

[dragonmantank]

This should be fixed with v3.2.2