[pkoird]

Closely related are in-code assertions. I remember when I used to liberally use asserts inside a code (and you could disable them for production) to check pre-conditions, post-conditions, or any invariants. Nowadays, I don't think the pattern is recommended anymore, at least in certain popular languages.

[just6979]

It's not recommended as much anymore because of unit tests. Instead of peppering the code with asserts, you build tests based on those assertions. You don't have to worry about turning it off in production because the tests are separate, and you also don't have to worry about manually triggering all the various asserts in a dev build, because the test runs are doing that for you even before a build is published.

[esafak]

Fail as early as you can, if you can't recover.