Merge pull request #1082 from georust/mkirk/fix-densify

FIX `Densify` trait to avoid panic with empty line string
georust · Oct 7, 2023 · d95daf8 · d95daf8
2 parents 2c99be6 + ad126cd
commit d95daf8
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Showing 2 changed files with 20 additions and 3 deletions.
diff --git a/geo/CHANGES.md b/geo/CHANGES.md
@@ -2,15 +2,19 @@
 
 ## Unreleased
 
-* Add `DensifyHaversine` trait to densify spherical line geometry
-* Add `LineStringSegmentize` trait to split a single `LineString` into `n` `LineStrings` as a `MultiLineString`
+* Fix `Densify` trait to avoid panic with empty line string.
+  * <https://github.com/georust/geo/pull/1082>
+* Add `DensifyHaversine` trait to densify spherical line geometry.
+  * <https://github.com/georust/geo/pull/1081>
+* Add `LineStringSegmentize` trait to split a single `LineString` into `n` `LineStrings` as a `MultiLineString`.
+  * <https://github.com/georust/geo/pull/1055>
 * Add `EuclideanDistance` implementations for all remaining geometries.
   * <https://github.com/georust/geo/pull/1029>
 * Add `HausdorffDistance` algorithm trait to calculate the Hausdorff distance between any two geometries.
   * <https://github.com/georust/geo/pull/1041>
 * Add `matches` method to IntersectionMatrix for ergonomic de-9im comparisons.
   * <https://github.com/georust/geo/pull/1043>
-* Simplify `CoordsIter` and `MinimumRotatedRect` `trait`s with GATs by removing an unneeded trait lifetime
+* Simplify `CoordsIter` and `MinimumRotatedRect` `trait`s with GATs by removing an unneeded trait lifetime.
   * <https://github.com/georust/geo/pull/908>
 * Add `ToDegrees` and `ToRadians` traits.
   * <https://github.com/georust/geo/pull/1070>

diff --git a/geo/src/algorithm/densify.rs b/geo/src/algorithm/densify.rs
@@ -106,7 +106,12 @@ where
     type Output = LineString<T>;
 
     fn densify(&self, max_distance: T) -> Self::Output {
+        if self.0.is_empty() {
+            return LineString::new(vec![]);
+        }
+
         let mut new_line = vec![];
+
         self.lines()
             .for_each(|line| densify_line(line, &mut new_line, max_distance));
         // we're done, push the last coordinate on to finish
@@ -207,6 +212,14 @@ mod tests {
         assert_eq!(densified, correct_polygon);
     }
 
+    #[test]
+    fn test_empty_linestring_densify() {
+        let linestring = LineString::<f64>::new(vec![]);
+        let max_dist = 2.0;
+        let densified = linestring.densify(max_dist);
+        assert!(densified.0.is_empty());
+    }
+
     #[test]
     fn test_linestring_densify() {
         let linestring: LineString<f64> =