From cf6c92320bd89c105618d56e3a0f6c8fbbe782f4 Mon Sep 17 00:00:00 2001
From: Wolfgang Bangerth <bangerth@colostate.edu>
Date: Thu, 17 Nov 2022 13:46:24 -0700
Subject: [PATCH] Re-introduce (now deprecated) old constructor.

---
 include/deal.II/lac/petsc_precondition.h | 10 +++++++++-
 source/lac/petsc_precondition.cc         |  6 ++++++
 2 files changed, 15 insertions(+), 1 deletion(-)

diff --git a/include/deal.II/lac/petsc_precondition.h b/include/deal.II/lac/petsc_precondition.h
index 16df0d8039..8b96a859fc 100644
--- a/include/deal.II/lac/petsc_precondition.h
+++ b/include/deal.II/lac/petsc_precondition.h
@@ -62,7 +62,15 @@ namespace PETScWrappers
     /**
      * Constructor.
      */
-    PreconditionBase(const MPI_Comm &mpi_communicator = MPI_COMM_NULL);
+    explicit PreconditionBase(const MPI_Comm &mpi_communicator);
+
+    /**
+     * Constructor. This constructor is deprecated.
+     *
+     * @deprecated
+     */
+    DEAL_II_DEPRECATED
+    PreconditionBase();
 
     /**
      * Destructor.
diff --git a/source/lac/petsc_precondition.cc b/source/lac/petsc_precondition.cc
index 6f145d31de..2124f58a0b 100644
--- a/source/lac/petsc_precondition.cc
+++ b/source/lac/petsc_precondition.cc
@@ -41,6 +41,12 @@ namespace PETScWrappers
 
 
 
+  PreconditionBase::PreconditionBase()
+    : PreconditionBase(MPI_COMM_NULL)
+  {}
+
+
+
   PreconditionBase::~PreconditionBase()
   {
     try
-- 
2.39.5