From 4fdd8684e716080dd66133aab2fdd6315d4ed561 Mon Sep 17 00:00:00 2001
From: Martin Kronbichler <kronbichler@lnm.mw.tum.de>
Date: Thu, 12 Apr 2018 10:10:46 +0200
Subject: [PATCH] Fix signal handling of transfinite interpolation once
 cleared.

---
 include/deal.II/grid/manifold_lib.h | 11 +++++++++++
 source/grid/manifold_lib.cc         | 13 +++++++++++--
 2 files changed, 22 insertions(+), 2 deletions(-)

diff --git a/include/deal.II/grid/manifold_lib.h b/include/deal.II/grid/manifold_lib.h
index a81d837c07..e2679fa140 100644
--- a/include/deal.II/grid/manifold_lib.h
+++ b/include/deal.II/grid/manifold_lib.h
@@ -831,6 +831,11 @@ public:
    */
   TransfiniteInterpolationManifold();
 
+  /**
+   * Destructor.
+   */
+  ~TransfiniteInterpolationManifold();
+
   /**
    * Make a clone of this Manifold object.
    */
@@ -996,6 +1001,12 @@ private:
    * use a FlatManifold description.
    */
   FlatManifold<dim> chart_manifold;
+
+  /**
+   * The connection to Triangulation::signals::clear that must be reset once
+   * this class goes out of scope.
+   */
+  boost::signals2::connection clear_signal;
 };
 
 DEAL_II_NAMESPACE_CLOSE
diff --git a/source/grid/manifold_lib.cc b/source/grid/manifold_lib.cc
index ea5f129b64..ab2178a473 100644
--- a/source/grid/manifold_lib.cc
+++ b/source/grid/manifold_lib.cc
@@ -1347,6 +1347,15 @@ TransfiniteInterpolationManifold<dim,spacedim>::TransfiniteInterpolationManifold
 
 
 
+template <int dim, int spacedim>
+TransfiniteInterpolationManifold<dim,spacedim>::~TransfiniteInterpolationManifold()
+{
+  if (clear_signal.connected())
+    clear_signal.disconnect();
+}
+
+
+
 template<int dim, int spacedim>
 std::unique_ptr<Manifold<dim, spacedim> >
 TransfiniteInterpolationManifold<dim,spacedim>::clone() const
@@ -1366,8 +1375,8 @@ TransfiniteInterpolationManifold<dim,spacedim>
 {
   this->triangulation = &triangulation;
   // in case the triangulatoin is cleared, remove the pointers by a signal
-  triangulation.signals.clear.connect
-  ([&]() -> void {this->triangulation = nullptr; this->level_coarse = -1;});
+  clear_signal = triangulation.signals.clear.connect
+                 ([&]() -> void {this->triangulation = nullptr; this->level_coarse = -1;});
   level_coarse = triangulation.last()->level();
   coarse_cell_is_flat.resize(triangulation.n_cells(level_coarse), false);
   typename Triangulation<dim,spacedim>::active_cell_iterator
-- 
2.39.5