nextExecution over daylight savings is wrong

[swanke00]

I want to schedule something to run every day at 17:00. Cron tab is "0 17 * * *". When the nextExecution crosses daylight savings time, the hour is 18:00 (or 16:00 during fall back). Here's my code:

    CronParser parser = new CronParser(CronDefinitionBuilder.instanceDefinitionFor(CronType.UNIX));
    // daily at 17:00
    ExecutionTime executionTime = ExecutionTime.forCron(parser.parse("0 17 * * *"));
    // Daylight savings for New York 2016 is Mar 13 at 2am
    DateTime last = new DateTime(2016, 3, 12, 17, 0, DateTimeZone.forID("America/New_York"));
    DateTime next = executionTime.nextExecution(last);

    long millis = next.getMillis() - last.getMillis();
    System.out.println("Last = " + last + ", Next Execution = " + next + ", diff = " + (millis / 3600000));

.. and the output is :

Last = 2016-03-12T17:00:00.000-05:00, Next Execution = 2016-03-13T18:00:00.000-04:00, diff = 24

Note: the next execution time is 18:00 instead of 17:00 and the time difference is 24 hours when it should be 23. When I run with November dates, the next execution hour is 16 and the diff is 24 hours instead of 25.

[jmrozanec]

@swanke00 Thank you for reporting this. Contributions are welcome!

[swanke00]

Adding to this issue. lastExecution() is also incorrect.
CronParser parser = new CronParser(CronDefinitionBuilder.instanceDefinitionFor(CronType.UNIX));
// daily at 17:00
ExecutionTime executionTime = ExecutionTime.forCron(parser.parse("0 17 * * *"));
// Daylight savings for New York 2016 is Mar 13 at 2am
DateTime now = new DateTime(2016, 3, 12, 17, 0, DateTimeZone.forID("America/Phoenix"));
DateTime next = executionTime.nextExecution(now);
DateTime last = executionTime.lastExecution(now);

    long millis = now.getMillis() - last.getMillis();
    System.out.println("Now  = " + now + ",\nLast = " + last + ",\nNext = " + next + ",\ndiff = "
            + (millis / 3600000));

the output is

Now = 2016-03-12T17:00:00.000-07:00,
Last = 2016-03-11T17:00:00.000-05:00,
Next = 2016-03-13T17:00:00.000-07:00,
diff = 26

Note the UTC offset of -5:00 which is my local timezone offset and a time difference of 26 hours due to the incorrect zone offset.

[jmrozanec]

@swanke00 thank you! If you have some time, would you write a test case for this? Be well!

[DanoOM]

cron-utils version 3.1.5
We ran into this on the last day light saving adjustment..
Starting at exactly 2:00am, all schedules were off by 1 hour, and it did not correct until 2/13 midnight.

Here is a code snippet, you can run prints out the runtimes for this cron expression: * 0/2 * * * ?
`
package test;
import java.text.SimpleDateFormat;
import java.util.Calendar;
import java.util.Date;
import java.util.TimeZone;

import com.cronutils.model.Cron;
import com.cronutils.model.CronType;
import com.cronutils.model.definition.CronDefinition;
import com.cronutils.model.definition.CronDefinitionBuilder;
import com.cronutils.model.time.ExecutionTime;
import com.cronutils.parser.CronParser;

import org.joda.time.DateTime;

public class BadDayLightSavings {

public static void BadDayLightSavings() {
    try {
        String expression = "* 0/2 * * * ?";
        Date startDate;        
        SimpleDateFormat sdf = new SimpleDateFormat("yyyy MM dd HH:mm:ss");
        startDate = sdf.parse("2016 03 13 00:00:59");

        Calendar cal = Calendar.getInstance(TimeZone.getTimeZone("UTC"));
        cal.setTime(startDate);
        CronDefinition cronDef = CronDefinitionBuilder.instanceDefinitionFor(CronType.QUARTZ);
        CronParser parser = new CronParser(cronDef);
        Cron cron = parser.parse(expression);
        DateTime currentTime = new DateTime(startDate);
        ExecutionTime executionTime = ExecutionTime.forCron(cron);
        int count = 24 * 60;
        for (int i = 0 ;i < count; i++) {
            // At daylight savings time: 02:00AM nextExecution advances 1 hour each time, until midnight
            DateTime nextRun = executionTime.nextExecution(currentTime);
            System.out.println("Scheduled At:" +currentTime.toDate()+ " NEXT RUN:" + nextRun.toDate());
            // do not reschedule for same minute
            while(currentTime.isBefore(nextRun)) {
                currentTime = currentTime.plusMinutes(1);
            }
        }        
    }
    catch(Exception e) {
        e.printStackTrace();
    }
}

}
`

[jmrozanec]

@DanoOM Thank you! Wouldn't you mind to turn this example into a test case for this issue? I will be eager to accept such a pull request.

[jmrozanec]

@DanoOM @swanke00 issue fixed!

[jmrozanec]

@swanke00 @DanoOM New version released! Please check details here