fix(engine): count each id Shape Builder is given once (#1974)

crates/engine/src/canvas/shapebuilder.rs

@@ -109,7 +109,9 @@ pub fn eligible(doc: &Document, ids: &[NodeId]) -> Vec<NodeId> {
             out.push(id);
         }
     }
-    let ids: Vec<NodeId> = ids.iter().copied().filter(|i| doc.contains(*i)).collect();
+    // Each id counts once: a repeated group must not be walked once per repeat.
+    let mut seen = std::collections::BTreeSet::new();
+    let ids: Vec<NodeId> = ids.iter().copied().filter(|i| doc.contains(*i) && seen.insert(*i)).collect();
     let mut out = Vec::new();
     for id in roots(doc, &ids) {
         walk(doc, id, 0, &mut out);

crates/engine/src/shapebuilder_tests.rs

@@ -217,6 +217,15 @@ fn remove_mode_and_escape() {
     assert!(s.execute("shapeBuilder.mode", &json!({"mode": "sideways"})).is_err());
 }
 
+#[test]
+fn a_group_named_many_times_is_walked_once() {
+    let mut s = Session::new();
+    let (a, b) = squares(&mut s);
+    let g = id(&ex(&mut s, "object.group", json!({"ids": [a, b]})));
+    let r = ex(&mut s, "shapeBuilder.regions", json!({"ids": vec![g; 500]}));
+    assert_eq!(r["sources"], json!([a, b]));
+}
+
 #[test]
 fn groups_rotated_and_ineligible_layers() {
     let mut s = Session::new();