From 0648c9ffaa4157fb7d62003417011a25c1bc1316 Mon Sep 17 00:00:00 2001
From: Wolfgang Bangerth <bangerth@colostate.edu>
Date: Tue, 15 Aug 2023 05:20:03 -0600
Subject: [PATCH] Clear some forgotten fields in Triangulation::clear().

---
 source/grid/tria.cc | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/source/grid/tria.cc b/source/grid/tria.cc
index dee32a5eb3..4b0c65fa41 100644
--- a/source/grid/tria.cc
+++ b/source/grid/tria.cc
@@ -16083,6 +16083,15 @@ void Triangulation<dim, spacedim>::clear_despite_subscriptions()
 
   manifolds.clear();
 
+  // In 1d, also reset vertex-to-(boundary|manifold) maps to empty maps
+  if (dim == 1)
+    {
+      vertex_to_boundary_id_map_1d =
+        std::make_unique<std::map<unsigned int, types::boundary_id>>();
+      vertex_to_manifold_id_map_1d =
+        std::make_unique<std::map<unsigned int, types::manifold_id>>();
+    }
+
   number_cache = internal::TriangulationImplementation::NumberCache<dim>();
 }
 
-- 
2.39.5