> If both the client and the routine check for the same conditions, the resulting redundancy, when accumulated over a large system, will yield the complexity and unwieldiness that are so characteristic of today's software.
... better check twice than not at all, reason the designers.
eg https://se.inf.ethz.ch/~meyer/publications/old/dbc_chapter.p...
> If both the client and the routine check for the same conditions, the resulting redundancy, when accumulated over a large system, will yield the complexity and unwieldiness that are so characteristic of today's software. ... better check twice than not at all, reason the designers.