[docheinestages]

I'm not disagreeing with your point. A good understanding of the domain and relevant systems is quite crucial. My point is that you don't always need to inspect the code at such low-level detail, provided there are tests or other ways to prove that the code behaves in the way that you describe.

[grayhatter]

> My point is that you don't always need to inspect the code at such low-level detail, provided there are tests or other ways to prove that the code behaves in the way that you describe.

This is true *only* in isolation. The pain of going through said depth of detail, is what builds the intuition for the whole system. Once and twice may not be noticeable, but a new habit, and that new habit's corresponding extreme downtime because no one understands the quirks anymore... Despite a few engineers who stake their life on the testing system, tests can't catch all issues. And it's extremely difficult to stop an oil tanker.