[GROOVY-7963] TimeDuration fields can overflow int resulting in negative duration

• Type: Bug
• Status: Open
• Priority: Major
• Resolution: Unresolved
• Affects Version/s: 2.4.6
• Labels: TimeDuration int overflow
• Assignee: Unassigned
• Reporter: Josef Sustacek
• Created: 10/Oct/16 12:20
• Updated: 10/Oct/16 12:23

Description

When you accidentally or on purposes add (.plus()) two time durations where some unit can no longer fit int, this unit will overflow in the new object. This can lead to negative duration and / or incorrect calculations with this new duration. When the duration still remains positive at the end (e.g. being 3 days, -20 hours type of duration), it can be very hard to spot the error.

Example code:

import groovy.time.TimeCategory

use (TimeCategory) {
    def duration = Integer.MAX_VALUE.milliseconds + 1.millisecond

    println duration
}

Result (groovy 2.4.6):

Result: -2147483.648 seconds

This is due to the fact that the BaseDuration has all units' fields implemented as int and the TimeDuration.plus() simply adds the ints of each unit of the two durations together, forming the new duration:

• https://github.com/groovy/groovy-core/blob/master/src/main/groovy/time/Duration.java#L42-L46

Expected: Either check this in all the .plus() }} methods and prevent such two durations to be added together, of use {{long for the units's fields to make sure they cannot overflow when two large {{int}}s are added together.