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Ask HN: Did you encounter any leap year bugs today?

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Re: Ask HN: Did you encounter any leap year bugs today?

#483

Post by sensanaty »

dr_kiszonka wrote: post #172

One thing I have learned from HN is that datetime issues are hard, prolific, programming language agnostic, and not to trust myself to get the logic right. (The same applies to floats.)

I haven't had too many true hair-pulling moments in my life as a programmer, but the majority of them were because of datetime issues.

My brain just doesn't get the concept I guess, I always struggle a lot whenever I need to touch anything that does anything with dates/time

Re: Ask HN: Did you encounter any leap year bugs today?

#487

Post by qup »

guappa wrote: post #427
qup wrote: post #402

Earlier quoted context omitted.

Can't get drafted at 17. I don't know if you can go or not.

Raffaele Minichiello volunteered at 17. https://it.wikipedia.org/wiki/Raffaele_Minichiello

Volunteering is the opposite of getting drafted

Re: Ask HN: Did you encounter any leap year bugs today?

#490

Post by js2 »

paulddraper wrote: post #340
js2 wrote: post #268

Earlier quoted context omitted.

Is March more logical? Feb 29 + 1 year = Feb 28.

You're begging the question. [1] "Feb 29 + 1 year" is verbatim restatement. --- You can say Feb 29 + 365 days = Feb 28. (And Feb 29 + 730 days = Feb 27.) --- EDIT: Note that in the context of birthdays, people use "calendar years," not "unit of time which is ~1 revolution around the sun." Birthdays aren't celebrated every X million seconds after the moment of birth. They are celebrated the same day each calendar year…

> what is the same day next (calendar) year?"

When I wrote "+ 1 year" I meant year to represent 365 or 365.25 days, not "the same day next year.":

  >>> from datetime import date, timedelta
  >>> year = timedelta(days=365.25)
  >>> date(2024, 2, 29) + year
  datetime.date(2025, 2, 28)
You may have interpreted it as begging the question, but it was not my intent—though I admit my formulation was ambiguous.

> Note that in the context of birthdays, people use "calendar years," not "unit of time which is ~1 revolution around the sun."

You've never heard someone say they've celebrated another trip around the Sun? I literally have a photo from 2007 of my daughter in Montessori celebrating her birthday by holding a globe and walking around a candle representing the Sun. I think most people probably don't really think about whether it's a calendar year or astronomical year because for most people, they are usually equivalent and it doesn't matter.

But that's all beside the point. All I meant to point out is that I disagree that March is more logical. I don't think logic points us to one month or the other. You may feel March is more logical, but I don't accept your priors, so for me March is not more logical than February.

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