diff -Nru dune-functions-2.7.0/debian/changelog dune-functions-2.7.1/debian/changelog
--- dune-functions-2.7.0/debian/changelog	2020-07-17 16:52:48.000000000 +0000
+++ dune-functions-2.7.1/debian/changelog	2021-01-13 09:53:16.000000000 +0000
@@ -1,8 +1,14 @@
-dune-functions (2.7.0-2build1) groovy; urgency=medium
+dune-functions (2.7.1-2) unstable; urgency=medium
 
-  * Rebuild against new dune 2.7.
+  * Upload to unstable.
 
- -- Gianfranco Costamagna <locutusofborg@debian.org>  Fri, 17 Jul 2020 18:52:48 +0200
+ -- Ansgar <ansgar@debian.org>  Wed, 13 Jan 2021 10:53:16 +0100
+
+dune-functions (2.7.1-1) experimental; urgency=medium
+
+  * New upstream release.
+
+ -- Lisa Julia Nebel <lisa_julia.nebel@tu-dresden.de>  Thu, 07 Jan 2021 10:49:29 +0100
 
 dune-functions (2.7.0-2) unstable; urgency=medium
 
diff -Nru dune-functions-2.7.0/debian/control dune-functions-2.7.1/debian/control
--- dune-functions-2.7.0/debian/control	2020-05-30 10:43:14.000000000 +0000
+++ dune-functions-2.7.1/debian/control	2021-01-07 14:00:24.000000000 +0000
@@ -9,10 +9,10 @@
 Homepage: https://www.dune-project.org/
 Build-Depends: debhelper-compat (= 13),
  cmake, gfortran, mpi-default-bin, mpi-default-dev, pkg-config, python3,
- libdune-localfunctions-dev (>= 2.7.0),
- libdune-grid-dev (>= 2.7.0),
- libdune-istl-dev (>= 2.7.0),
- libdune-typetree-dev (>= 2.7.0)
+ libdune-localfunctions-dev (>= 2.7.1),
+ libdune-grid-dev (>= 2.7.1),
+ libdune-istl-dev (>= 2.7.1),
+ libdune-typetree-dev (>= 2.7.1)
 Build-Depends-Indep: doxygen, ghostscript, graphviz, imagemagick, texlive-latex-extra, texlive-latex-recommended, texlive-pictures
 Rules-Requires-Root: no
 
@@ -20,9 +20,9 @@
 Section: libdevel
 Architecture: all
 Depends: ${misc:Depends},
- libdune-localfunctions-dev (>= 2.7.0),
- libdune-grid-dev (>= 2.7.0),
- libdune-typetree-dev (>= 2.7.0)
+ libdune-localfunctions-dev (>= 2.7.1),
+ libdune-grid-dev (>= 2.7.1),
+ libdune-typetree-dev (>= 2.7.1)
 Suggests: libdune-functions-doc (= ${source:Version})
 Description: toolbox for solving PDEs -- interface for functions (development files)
  DUNE, the Distributed and Unified Numerics Environment is a modular toolbox
diff -Nru dune-functions-2.7.0/dune/functions/common/polymorphicsmallobject.hh dune-functions-2.7.1/dune/functions/common/polymorphicsmallobject.hh
--- dune-functions-2.7.0/dune/functions/common/polymorphicsmallobject.hh	2020-01-12 13:35:54.000000000 +0000
+++ dune-functions-2.7.1/dune/functions/common/polymorphicsmallobject.hh	2020-10-29 19:47:28.000000000 +0000
@@ -4,6 +4,7 @@
 #define DUNE_FUNCTIONS_COMMON_POLYMORPHICSMALLOBJECT_HH
 
 #include <utility>
+#include <type_traits>
 
 #include <dune/common/std/type_traits.hh>
 #include <dune/common/hybridutilities.hh>
@@ -33,11 +34,11 @@
  * that Base has a virtual destructor.
  *
  * In order to make the copy constructor work for polymorphic types,
- * Base must provide virtual methods clone() and clone(void*). The former should return
- * a pointer to a dynamically allocated clone, while the latter
- * should call the appropriate placement-new with the passed pointer.
+ * Base must provide virtual methods `Base* clone()` and `Base* clone(void*)`.
+ * The former should return a pointer to a dynamically allocated clone, while
+ * the latter should call the appropriate placement-new with the passed pointer.
  *
- * Similarly the polymorphic type has to implement a virtual move(void*)
+ * Similarly the polymorphic type has to implement a virtual `Base* move(void*)`
  * method.
  * This should call placement-new and can std::move all the
  * data but leave the object in a valid and probably unusable state.
@@ -55,16 +56,18 @@
   /**
    * \brief Construct from object
    *
-   * \tparam Derived Type of object to be stored, should be derived from Base
+   * \tparam Derived Type of object to be stored, must be derived from Base
    * \param derived Object to be stored
    */
-  template<class Derived>
+  template<class Derived,
+        typename std::enable_if<std::is_base_of<Base, std::remove_cv_t<
+          std::remove_reference_t<Derived>>>::value, int>::type = 0>
   PolymorphicSmallObject(Derived&& derived)
   {
     using namespace Dune::Hybrid;
-    auto useBuffer = Dune::Std::bool_constant<(sizeof(Derived)<bufferSize)>();
+    auto useBuffer = Dune::Std::bool_constant<(sizeof(Derived) <= bufferSize)>();
     ifElse(useBuffer, [&](auto id) {
-      p_ = new (buffer_) Derived(std::forward<Derived>(derived));
+      p_ = new (&buffer_) Derived(std::forward<Derived>(derived));
     }, [&](auto id) {
       p_ = new Derived(std::forward<Derived>(derived));
     });
@@ -91,8 +94,11 @@
   //! Copy assignment from other PolymorphicSmallObject
   PolymorphicSmallObject& operator=(const PolymorphicSmallObject& other)
   {
-    destroyWrappedObject();
-    copyToWrappedObject(other);
+    if (&other!=this)
+    {
+      destroyWrappedObject();
+      copyToWrappedObject(other);
+    }
     return *this;
   }
 
@@ -144,12 +150,12 @@
   void moveToWrappedObject(PolymorphicSmallObject&& other)
   {
     if (other.bufferUsed())
-      p_ = other.p_->move(buffer_);
+      p_ = other.p_->move(&buffer_);
     else
     {
       // We don't need to check for &other_!=this, because you can't
       // have an rvalue to *this and call it's assignment/constructor
-      // at the same time. (Despite trying to shot yourself in the foot
+      // at the same time. (Despite trying to shoot yourself in the foot
       // with std::move explicitly.)
 
       // Take ownership of allocated object
@@ -162,16 +168,13 @@
 
   void copyToWrappedObject(const PolymorphicSmallObject& other)
   {
-    if (&other!=this)
-    {
-      if (other.bufferUsed())
-        p_ = other.p_->clone(buffer_);
-      else
-        p_ = other.p_->clone();
-    }
+    if (other.bufferUsed())
+      p_ = other.p_->clone(&buffer_);
+    else
+      p_ = other.p_->clone();
   }
 
-  alignas(Base) char buffer_[bufferSize];
+  std::aligned_storage_t<bufferSize> buffer_;
   Base* p_;
 };
 
diff -Nru dune-functions-2.7.0/dune/functions/common/test/CMakeLists.txt dune-functions-2.7.1/dune/functions/common/test/CMakeLists.txt
--- dune-functions-2.7.0/dune/functions/common/test/CMakeLists.txt	2020-01-12 13:35:54.000000000 +0000
+++ dune-functions-2.7.1/dune/functions/common/test/CMakeLists.txt	2020-10-29 19:47:28.000000000 +0000
@@ -1,3 +1,4 @@
 # tests that should build and run successfully
 
 dune_add_test(SOURCES differentiablefunctiontest.cc)
+dune_add_test(SOURCES polymorphicsmallobjecttest.cc)
diff -Nru dune-functions-2.7.0/dune/functions/common/test/polymorphicsmallobjecttest.cc dune-functions-2.7.1/dune/functions/common/test/polymorphicsmallobjecttest.cc
--- dune-functions-2.7.0/dune/functions/common/test/polymorphicsmallobjecttest.cc	1970-01-01 00:00:00.000000000 +0000
+++ dune-functions-2.7.1/dune/functions/common/test/polymorphicsmallobjecttest.cc	2020-10-29 19:47:28.000000000 +0000
@@ -0,0 +1,106 @@
+// -*- tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+// vi: set et ts=4 sw=2 sts=2:
+#include <config.h>
+
+#include <dune/common/exceptions.hh>
+#include <dune/common/parallel/mpihelper.hh>
+#include <dune/functions/common/polymorphicsmallobject.hh>
+
+#include <array>
+#include <iostream>
+#include <string>
+#include <utility>
+
+class Base
+{
+public:
+  virtual ~Base() = default;
+  virtual Base* clone() = 0;
+  virtual Base* clone(void*) = 0;
+  virtual Base* move(void*) = 0;
+  virtual int foo() = 0;
+  virtual bool checkMemberAlignment() = 0;
+};
+
+class Derived
+    : public virtual Base
+{
+  long double dummy_;
+  int i_;
+public:
+  virtual ~Derived() = default;
+  Derived(int i = 0) : i_(i) {}
+  Base* clone() final { return new Derived{i_}; }
+  Base* clone(void* ptr) final { return new (ptr) Derived{this->i_}; }
+  Base* move(void* ptr) final { return new (ptr) Derived{std::move(this->i_)}; }
+  int foo() final { return i_; }
+  bool checkMemberAlignment() final {
+    return (reinterpret_cast<std::uintptr_t>(&dummy_) % alignof(long double)) == 0;
+  }
+};
+
+bool checkTrue(bool value, std::string error)
+{
+  if (not(value))
+    std::cout << "TEST FAILURE:" << error << std::endl;
+  return value;
+}
+
+template <class Obj>
+bool test()
+{
+  bool success = true;
+
+  std::array<Obj,2> v{Derived{2}, Derived{2}};
+  success &= checkTrue(v[0].get().checkMemberAlignment(), "Invalid alignment of member!");
+  success &= checkTrue(v[1].get().checkMemberAlignment(), "Invalid alignment of member!");
+
+  Obj obj(Derived{2});
+  success &= checkTrue(obj.get().foo() == 2, "Invalid state using constructor with Derived argument!");
+
+  Obj objCopy(obj);
+  success &= checkTrue(objCopy.get().foo() == 2, "Invalid state using copy constructor!");
+
+  Obj objMove(std::move(objCopy));
+  success &= checkTrue(objMove.get().foo() == 2, "Invalid state using move constructor!");
+
+  Obj objCopyAssign = obj;
+  success &= checkTrue(objCopyAssign.get().foo() == 2, "Invalid state using copy assignment!");
+
+  Obj objMoveAssign = std::move(objCopyAssign);
+  success &= checkTrue(objMoveAssign.get().foo() == 2, "Invalid state using move assignment!");
+
+  obj = obj;
+  success &= checkTrue(obj.get().foo() == 2, "Invalid state using self assignment!");
+
+  return success;
+}
+
+int main ( int argc, char **argv )
+try
+{
+  Dune::MPIHelper::instance(argc, argv);
+  bool passed = true;
+
+  std::cout << "Testing PolymorphicSmallObject with no buffer" << std::endl;
+  passed &= test<Dune::Functions::PolymorphicSmallObject<Base, 0>>();
+
+  std::cout << "Testing PolymorphicSmallObject with buffer" << std::endl;
+  constexpr std::size_t OBJSIZE = sizeof(Derived);
+  passed &= test<Dune::Functions::PolymorphicSmallObject<Base, OBJSIZE>>();
+
+  if (passed)
+    std::cout << "All tests passed" << std::endl;
+
+  return passed ? 0: 1;
+}
+catch( Dune::Exception &e )
+{
+  std::cerr << "Dune reported error: " << e << std::endl;
+  return 1;
+}
+catch(...)
+{
+  std::cerr << "Unknown exception thrown!" << std::endl;
+  return 1;
+}
diff -Nru dune-functions-2.7.0/dune.module dune-functions-2.7.1/dune.module
--- dune-functions-2.7.0/dune.module	2020-01-12 13:35:54.000000000 +0000
+++ dune-functions-2.7.1/dune.module	2020-10-29 19:47:28.000000000 +0000
@@ -1,7 +1,7 @@
 # Dune module information file
 
 Module: dune-functions
-Version: 2.7.0
+Version: 2.7.1
 Maintainer: dune-functions@lists.dune-project.org
 Depends:  dune-localfunctions (>= 2.7) dune-grid (>= 2.7) dune-istl (>= 2.7) dune-typetree (>= 2.7)
 Whitespace-Hook: Yes
diff -Nru dune-functions-2.7.0/.gitlab-ci.yml dune-functions-2.7.1/.gitlab-ci.yml
--- dune-functions-2.7.0/.gitlab-ci.yml	2020-01-12 13:35:54.000000000 +0000
+++ dune-functions-2.7.1/.gitlab-ci.yml	2020-10-29 19:47:28.000000000 +0000
@@ -1,7 +1,11 @@
 ---
 include:
-  - "https://gitlab.dune-project.org/core/ci-config/raw/master/config/common/master.yml"
-  - "https://gitlab.dune-project.org/core/ci-config/raw/master/jobs/common/master.yml"
+  - project: 'core/ci-config'
+    ref: master
+    file: 'config/common/releases/2.7.yml'
+  - project: 'core/ci-config'
+    ref: master
+    file: 'jobs/common/releases/2.7.yml'
 
 before_script:
   - . /duneci/bin/duneci-init-job