The Daily WTF: Curious Perversions in Information Technology

2014-09-23 Reply Admin

anonymous:
...unless it's February?

See bold:

nmclean:
I don't know what you're talking about, but I don't see why it needs to be this complicated. There is only a problem when the unit of time you want to work with is ambiguous. If we know that we want to work in months or years, we shouldn't be putting 30 or 365 days into the system in the first place; we should be adjusting the month or year component directly (and temporarily rolling back the day-of-month as needed when it is out of bounds). How are there 9 different answers to this?

This is how any human given the same instructions would handle this problem, and how various APIs do it. It's not that complicated or open to interpretation.

2014-09-23 Reply Admin

nmclean:
Neil:
Do we know that AddYears(21) won't stumble over a DST transition and therefore result in a date that's an hour off?
No. Basically, it just adjusts the Year component of the date and makes no other assumptions: 1980/X/X + 21y = 2001/X/X. If X/X is Feb 29, and the resulting year is not a leap year, it just adjusts it to Feb 28 (this means that AddYears(3).AddYears(1) doesn't necessarily give the same result as AddYears(4)).

TRWTF is Earth.

2014-09-24 Reply Admin

Norman Diamond:
nmclean:
Neil:
Do we know that AddYears(21) won't stumble over a DST transition and therefore result in a date that's an hour off?
No. Basically, it just adjusts the Year component of the date and makes no other assumptions: 1980/X/X + 21y = 2001/X/X. If X/X is Feb 29, and the resulting year is not a leap year, it just adjusts it to Feb 28 (this means that AddYears(3).AddYears(1) doesn't necessarily give the same result as AddYears(4)).
TRWTF is Earth.

Earth's own cycle is far more consistent, and none of these issues would exist if all time was measured in nothing but pure integer divisions of it.

2014-09-24 Reply Admin

nmclean:
Norman Diamond:
nmclean:
Neil:
Do we know that AddYears(21) won't stumble over a DST transition and therefore result in a date that's an hour off?
No. Basically, it just adjusts the Year component of the date and makes no other assumptions: 1980/X/X + 21y = 2001/X/X. If X/X is Feb 29, and the resulting year is not a leap year, it just adjusts it to Feb 28 (this means that AddYears(3).AddYears(1) doesn't necessarily give the same result as AddYears(4)).
TRWTF is Earth.
Earth's own cycle is far more consistent, and none of these issues would exist if all time was measured in nothing but pure integer divisions of it.

A day isn't an integer division of a year. TRWTF is Earth.

The moon's rotation is the same as its revolution with respect to Earth, but not with respect to the sun. So TRWTF is still Earth.

2014-09-24 Reply Admin

if you read the whole thing, there wasn't an issue with the feb 29 logs.

2014-09-30 Reply Admin

The only thing wrong with this code is everything.

2021-07-31 Reply Admin

Joking aside!

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2021-08-08 Reply Admin

Should you tell it — a false way.

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