if there are no edges, _magic_hopf should return false

zxcalc · Jul 24, 2024 · 40d0ea0 · 40d0ea0
1 parent e80a835
commit 40d0ea0
Showing 1 changed file with 2 additions and 0 deletions.
diff --git a/zxlive/proof_panel.py b/zxlive/proof_panel.py
@@ -181,6 +181,8 @@ def _magic_hopf(self, trace: WandTrace) -> bool:
         if not all(isinstance(item, EItem) for item in trace.hit):
             return False
         edges = [item.e for item in trace.hit]
+        if len(edges) == 0:
+            return False
         if not all(edge == edges[0] for edge in edges):
             return False
         source, target = self.graph.edge_st(edges[0])