why does WalkBuilder::filter_entry() require a 'static closure?

[matthiasbeyer]

ripgrep/crates/ignore/src/walk.rs

Line 899 in 7099e17

P: Fn(&DirEntry) -> bool + Send + Sync + 'static,

This argument restriction seems weirdly restrictive to me. Is there any particular reason why the closure one has to pass in has to be a pure function (Fn + 'static)? Any chance that these might get lifted?

[BurntSushi]

It doesn't have to be a pure function. The 'static just means it can't borrow anything. That's very different from what a "pure" function is.

I don't have the specific context, but you might consider changing the signature to what you want and seeing what breaks. Consider, for example, that spawning a thread has a similar restriction.

[matthiasbeyer]

The 'static just means it can't borrow anything. That's very different from what a "pure" function is.

You're absolutely right of course... bad wording on my side.

Thanks for your fast reply and sorry that I didn't open this as a discussion in the first place. ❤️