7aceff4d13
## Issue Addressed Closes #1098 ## Proposed Changes Add a `SafeArithIter` trait with a `safe_sum` method, and use it in `state_processing`. This seems to be the only place in `consensus` where it is relevant -- i.e. where we were using `sum` and the integer_arith lint is enabled. ## Additional Info This PR doesn't include any Clippy linting to prevent `sum` from being called. It seems there is no existing Clippy lint that suits our purpose, but I'm going to look into that and maybe schedule writing one as a lower-priority task. This theoretically _is_ a consensus breaking change, but it shouldn't impact Medalla (or any other testnet) because `slashings` shouldn't overflow!
71 lines
1.7 KiB
Rust
71 lines
1.7 KiB
Rust
use crate::{Result, SafeArith};
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/// Extension trait for iterators, providing a safe replacement for `sum`.
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pub trait SafeArithIter<T> {
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fn safe_sum(self) -> Result<T>;
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}
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impl<I, T> SafeArithIter<T> for I
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where
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I: Iterator<Item = T> + Sized,
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T: SafeArith,
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{
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fn safe_sum(mut self) -> Result<T> {
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self.try_fold(T::ZERO, |acc, x| acc.safe_add(x))
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}
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}
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#[cfg(test)]
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mod test {
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use super::*;
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use crate::ArithError;
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#[test]
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fn empty_sum() {
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let v: Vec<u64> = vec![];
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assert_eq!(v.into_iter().safe_sum(), Ok(0));
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}
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#[test]
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fn unsigned_sum_small() {
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let v = vec![400u64, 401, 402, 403, 404, 405, 406];
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assert_eq!(
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v.iter().copied().safe_sum().unwrap(),
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v.iter().copied().sum()
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);
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}
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#[test]
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fn unsigned_sum_overflow() {
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let v = vec![u64::MAX, 1];
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assert_eq!(v.into_iter().safe_sum(), Err(ArithError::Overflow));
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}
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#[test]
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fn signed_sum_small() {
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let v = vec![-1i64, -2i64, -3i64, 3, 2, 1];
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assert_eq!(v.into_iter().safe_sum(), Ok(0));
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}
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#[test]
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fn signed_sum_overflow_above() {
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let v = vec![1, 2, 3, 4, i16::MAX, 0, 1, 2, 3];
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assert_eq!(v.into_iter().safe_sum(), Err(ArithError::Overflow));
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}
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#[test]
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fn signed_sum_overflow_below() {
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let v = vec![i16::MIN, -1];
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assert_eq!(v.into_iter().safe_sum(), Err(ArithError::Overflow));
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}
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#[test]
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fn signed_sum_almost_overflow() {
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let v = vec![i64::MIN, 1, -1i64, i64::MAX, i64::MAX, 1];
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assert_eq!(
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v.iter().copied().safe_sum().unwrap(),
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v.iter().copied().sum()
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);
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}
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}
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