Is it possible to predict stack overflow?

Question

I have a Rust program that uses recursion. Sometimes it hits "stack overflow" runtime error. I want to prevent this from happening. Instead, I want to have something like this inside my recursive function:

fn foo() -> u32 {
  if stack_is_almost_full() {
    panic!("Something is wrong with the recursion!");
  }
  // continue normally
}

Is it possible?

Answer 1

You can get an estimate for the remaining stack space from stacker::remaining_stack.

But for detecting problems with recursion some more direct approach might be more appropriate:

const MAX_DEPTH: usize = 1024;
#[inline(always)]
fn foo() -> u32 {
    foo_rec(0).expect("MAX_DEPTH reached while recursing")
}

fn foo_rec(depth: usize) -> Option<u32> {
    if depth > MAX_DEPTH {
        None
    }
    // do your work possibly recursing, finally return something
    if should_recurse() {
        foo_rec(depth + 1)
    } else {
        Some(42)
    }
}

fn should_recurse() -> bool {
    true // uh-oh
}