These methods are confusing because the arguments are backwards. I feel
like they should have never been added to `Option<T>` and that clippy
should suggest rewriting to
`map(...).unwrap_or(...)`/`map(...).unwrap_or_else(|| ...)`
https://github.com/rust-lang/rfcs/issues/1025
This is implemented in such a way that it should still allow processes
to go through when a file lock wasn't properly cleaned up and the OS
hasn't released it yet (but with a 200ms-ish delay).
Closes #18039
We currently only do this for fmt. This makes it so they're excluded by
default, but you can still opt into these directories by explicitly
specifying them.
