Document that wrap_optimal_fit panics

mgeisler · Dec 28, 2020 · d9ebda2 · d9ebda2
1 parent bba043c
commit d9ebda2
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diff --git a/fuzz/fuzz_targets/wrap_optimal_fit.rs b/fuzz/fuzz_targets/wrap_optimal_fit.rs
@@ -23,6 +23,8 @@ fuzz_target!(|input: (Vec<BoxGluePenalty>, u64)| {
             .and_then(|sum| sum.checked_add(f.penalty_width()))
     });
     if total_width.is_none() {
+        // The total width overflows usize — this is not supported so
+        // return here to avoid a crash.
         return;
     }
 

diff --git a/src/core.rs b/src/core.rs
@@ -671,6 +671,11 @@ const HYPHEN_PENALTY: usize = 25;
 /// by Knuth and Plass. The implementation here is based on [Python
 /// code by David
 /// Eppstein](https://github.com/jfinkels/PADS/blob/master/pads/wrap.py).
+///
+/// # Panics
+///
+/// The total width of all fragments must fit inside an `usize`
+/// (including the whitespace and penalty widths).
 pub fn wrap_optimal_fit<'a, T: Fragment, F: Fn(usize) -> usize>(
     fragments: &'a [T],
     line_widths: F,