Error while getting next run date

[the-prksh]

Hello,

An unusual error we encountered on 31.12.2024. Upon further investigation, we believe that it may be due to a potential bug in the library.

Here is the way to reproduce the error in IEX:

$ iex
iex(1)> Mix.install [{:crontab, “~> 1.1”}]
:ok

iex(2)> expression = Crontab.CronExpression.Parser.parse!(“0 9 2 1 * 2025”)
~e[0 9 2 1 * 2025]

iex(3)> Crontab.Scheduler.get_next_run_date(expression, ~N[2024-12-31 20:27:53.909514])
{:error, “No compliant date was found for your interval.”}

For other dates its works as expected -

iex(4)> Crontab.Scheduler.get_next_run_date(expression, ~N[2024-12-30 20:27:53.909514])
{:ok, ~N[2025-01-02 09:00:00]}

iex(5)> Crontab.Scheduler.get_next_run_date(expression, ~N[2024-12-29 20:27:53.909514])
{:ok, ~N[2025-01-02 09:00:00]}

Could anyone please provide an explanation of what is causing this error and whether it is expected behavior?

[NicolayD]

I think this bug happens only on Dec 31 of a leap year (in this case 2024). I saw the year incrementation was updated relatively recently (3 months ago), but this happens both with 1.1.13 and 1.1.14, haven't looked yet into more details with the code from 1.1.14.

[maennchen]

Thanks for the report. This has already been resolved on main while implementing full DateTime support.

The next release however depends on #133, so you'll have to be a bit patient.

The current main should be reasonably stable however, you should be able to use it for the moment with {:crontab, github: "maennchen/crontab"} in your mix.exs.

[NicolayD]

@maennchen just tested and that seems to work, thanks a lot for the response!