[mannykannot]

The sort of programs you are writing about can easily exhibit the sort of problem that yakubin is giving an example of - here's a comparable example:

  wasBusinessDay(date): Date.dayOfWeek(date) not in (Date.Saturday, Date.Sunday)

Which is as trivial as yakubin's example, but can fail for more, and much more nuanced, reasons - and no, you are not, in general, going to find an off-the-shelf answer to the question of whether your particular business was operating on a given day.

Both your claim that a big problem is things not working as they are supposed to[1], and the fact that the same old basic security problems get repeated in every new platform that comes along, show that libraries have not, in practice, been any sort of panacea for business software.

[1] I suspect you are referring to application code rather than library code, but either will do for the point I am making here.