Fix GlobalVertex duplication in sweep algorithm

crates/fj-kernel/src/algorithms/sweep/mod.rs

@@ -6,9 +6,14 @@ mod face;
 mod sketch;
 mod vertex;
 
+use std::collections::BTreeMap;
+
 use fj_math::Vector;
 
-use crate::objects::Objects;
+use crate::{
+    objects::{GlobalVertex, Objects},
+    storage::{Handle, ObjectId},
+};
 
 /// Sweep an object along a path to create another object
 pub trait Sweep: Sized {
@@ -38,4 +43,7 @@ pub trait Sweep: Sized {
 ///
 /// See [`Sweep`].
 #[derive(Default)]
-pub struct SweepCache;
+pub struct SweepCache {
+    /// Cache for global vertices
+    pub global_vertex: BTreeMap<ObjectId, Handle<GlobalVertex>>,
+}

crates/fj-kernel/src/algorithms/sweep/vertex.rs

@@ -126,14 +126,22 @@ impl Sweep for Handle<GlobalVertex> {
     fn sweep_with_cache(
         self,
         path: impl Into<Vector<3>>,
-        _: &mut SweepCache,
+        cache: &mut SweepCache,
         objects: &Objects,
     ) -> Self::Swept {
         let curve = GlobalCurve::new(objects);
 
         let a = self.clone();
-        let b =
-            GlobalVertex::from_position(self.position() + path.into(), objects);
+        let b = cache
+            .global_vertex
+            .entry(self.id())
+            .or_insert_with(|| {
+                GlobalVertex::from_position(
+                    self.position() + path.into(),
+                    objects,
+                )
+            })
+            .clone();
 
         let vertices = [a, b];
         let global_edge = GlobalEdge::new(curve, vertices.clone());