169. File::create_new — Atomic 'Create Only If It Doesn't Exist'

Fri, 29 May 2026 09:00:00 +0100

You want to write a config file, a lockfile, or a “did we run yet” sentinel — but only if it isn’t already there. The if path.exists() { … } else { File::create(path) } pattern looks fine until two processes hit it at the same time. There’s a one-line fix sitting in std::fs.

Atomic on rustbites

169. File::create_new — Atomic 'Create Only If It Doesn't Exist'