From f8183521ffe24c43cd6ca45f1163f6ee90f19625 Mon Sep 17 00:00:00 2001
From: Stefan Altmayer <stoeoef@gmail.com>
Date: Tue, 13 Aug 2024 22:09:01 +0200
Subject: [PATCH] Fix: Calling any `locate` method with any `NAN` coordinates
 would return arbitrary results.

It is better to systematically crash instead.
---
 src/delaunay_core/triangulation_ext.rs | 21 +++++++++++++++++++++
 src/triangulation.rs                   | 16 ++++++++++++++++
 2 files changed, 37 insertions(+)

diff --git a/src/delaunay_core/triangulation_ext.rs b/src/delaunay_core/triangulation_ext.rs
index 8119283..2186535 100644
--- a/src/delaunay_core/triangulation_ext.rs
+++ b/src/delaunay_core/triangulation_ext.rs
@@ -448,6 +448,10 @@ pub trait TriangulationExt: Triangulation {
         target_position: Point2<<Self::Vertex as HasPosition>::Scalar>,
         start: FixedVertexHandle,
     ) -> PositionInTriangulation {
+        let pos = target_position.to_f64();
+        assert!(!f64::is_nan(pos.x));
+        assert!(!f64::is_nan(pos.y));
+
         if self.num_vertices() < 2 {
             return match self.vertices().next() {
                 Some(single_vertex) if single_vertex.position() == target_position => {
@@ -953,6 +957,23 @@ mod test {
         Ok(())
     }
 
+    #[test]
+    #[should_panic]
+    fn test_locate_nan_empty() {
+        let d = DelaunayTriangulation::<Point2<f64>>::default();
+        d.locate(Point2::new(0.0, f64::NAN));
+    }
+
+    #[test]
+    #[should_panic]
+    fn test_locate_nan() {
+        let points = random_points_with_seed(20, SEED);
+        let d = DelaunayTriangulation::<Point2<f64>>::bulk_load(points);
+        if let Ok(d) = d {
+            d.locate(Point2::new(0.0, f64::NAN));
+        }
+    }
+
     #[test]
     fn test_iterate_faces() -> Result<(), InsertionError> {
         const SIZE: usize = 1000;
diff --git a/src/triangulation.rs b/src/triangulation.rs
index 4602341..be7096d 100644
--- a/src/triangulation.rs
+++ b/src/triangulation.rs
@@ -395,6 +395,10 @@ pub trait Triangulation: Default {
     }
 
     /// Returns information about the location of a point in a triangulation.
+    ///
+    /// # Panics
+    ///
+    /// Panics if the target point has any `NAN` coordinate.
     fn locate(
         &self,
         point: Point2<<Self::Vertex as HasPosition>::Scalar>,
@@ -406,6 +410,10 @@ pub trait Triangulation: Default {
     /// Locates a vertex at a given position.
     ///
     /// Returns `None` if the point could not be found.
+    ///
+    /// # Panics
+    ///
+    /// Panics if the target point has any `NAN` coordinate.
     #[allow(clippy::type_complexity)]
     fn locate_vertex(
         &self,
@@ -440,6 +448,10 @@ pub trait Triangulation: Default {
     /// The hint should be a vertex close to the position that
     /// is being looked up.
     ///
+    /// # Panics
+    ///
+    /// Panics if the target vertex has any `NAN` coordinate.
+    ///
     /// *See also [locate](Triangulation::locate), [locate_vertex](Triangulation::locate_vertex)*
     fn locate_with_hint(
         &self,
@@ -474,6 +486,10 @@ pub trait Triangulation: Default {
     /// This method will invalidate all vertex, edge and face handles
     /// upon successful removal.
     ///
+    /// # Panics
+    ///
+    /// Panics if the target position has any `NAN` coordinate.
+    ///
     /// *See also [remove](Triangulation::remove)*
     fn locate_and_remove(
         &mut self,