Comment by wongarsu
24 days ago
Seconds are also unambiguous. Depending on your chosen definition, "X days" may or may not be influenced by leap seconds and DST changes.
I doubt anyone cares about an hour more or less in this context. But if you want multiple implementations to agree talking about seconds on a monotonic timer is a lot simpler
Could you explain what you mean re: ambiguity? I understand why “calendar units” like months are ambiguous, but minutes, hours, days, and weeks all have fixed durations (which is why APIs like Python’s `timedelta` allows them).
The minute between December 31, 2016 23:59 and January 1st 2017 is 61 seconds, not 60 seconds. The hour that contains that minute is 3601 seconds, the day that contains that hour is 43201 seconds, etc. If you assume a fixed duration and simply multiply by 43200, your math will be wrong compared to the rest of the world.
Daylight savings time makes a day take 23 hours or 25 hours. That makes a week take 7254000 seconds or 7261200 seconds. Etc.
That’s what I mean by calendar units. These aren’t issues if you don’t try to apply durations to the “real” calendar.
(This is all in the context of cooldowns, where I’m not convinced the there’s any real ambiguity risk by allowing the user to specify a duration in day or hour units rather than seconds. In that context a day is exactly 24 hours, regardless of what your local savings time rules are.)
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Leap seconds are their own nightmare. UNIX time ignores them, btw, so that the unix epoch is 86400*number of days since 1/1/1970 + number of seconds since midnight. The behavior at the instance of a leap second is undefined.
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In the UK last Sunday was 23 hours long because we switched to BST, and occasionally leap seconds will result in a minute being something other 60 seconds.
No it wasn't. The country instantaneously changed timezones from UTC+0 to UTC+1 (called something else locally), it was no different to any other timezone change from e.g. physically moving into another timezone.
exploiting the ambiguity in date formats by releasing a package during a leap second
I came here to argue the opposite. Expressing it in seconds takes away questions about time zones and DST.
I think you're incorrect to say that second are also ambiguous. Maybe what you mean is that days are more practical, but that seems very much a personal preference.
I understand the [flawed] reasoning behind "x seconds from now is going to be roughly now() + x on this particular system", but how does defining the cooldown from an external timestamp save you from dealing with DST and other time shenanigans? In the end you are comparing two timestamps and that comparison is erroneous without considering time shenanigans
I think you misread the comment you're replying to.
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