I’m not saying it’s not possible to do correctly. But do you not agree that the first is hard to correctly (can overlook an fd) while the latter is a lot of complexity?

There is the CLOEXEC flag which is the intended way to manage this but it’s not the default and you have to be diligent about setting it which again carries its own set of challenges.

What you’d really want is CLOEXEC implicitly on all fds and having to explicitly opt in for fd inheritance.