OpenMPI: add +cxx variant (#15477)

* OpenMPI: add +cxx variant

* C++ support will be removed in 5.0.X release

1 files changed, 18 insertions, 10 deletions

diff --git a/var/spack/repos/builtin/packages/openmpi/package.py b/var/spack/repos/builtin/packages/openmpi/package.py
index a2b75bd67e..00cae9023b 100644
--- a/var/spack/repos/builtin/packages/openmpi/package.py
+++ b/var/spack/repos/builtin/packages/openmpi/package.py
@@ -77,7 +77,7 @@ class Openmpi(AutotoolsPackage):
 
     maintainers = ['hppritcha']
 
-    version('develop', branch='master')
+    version('master', branch='master')
 
     # Current
     version('4.0.3', sha256='1402feced8c3847b3ab8252165b90f7d1fa28c23b6b2ca4632b6e4971267fd03')  # libmpi.so.40.20.3
@@ -237,7 +237,8 @@ class Openmpi(AutotoolsPackage):
             description='Enable MPI_THREAD_MULTIPLE support')
     variant('cuda', default=False, description='Enable CUDA support')
     variant('pmi', default=False, description='Enable PMI support')
-    variant('cxx_exceptions', default=True, description='Enable C++ Exception support')
+    variant('cxx', default=False, description='Enable C++ MPI bindings')
+    variant('cxx_exceptions', default=False, description='Enable C++ Exception support')
     # Adding support to build a debug version of OpenMPI that activates
     # Memchecker, as described here:
     #
@@ -299,6 +300,10 @@ class Openmpi(AutotoolsPackage):
     conflicts('schedulers=loadleveler', when='@3.0.0:',
               msg='The loadleveler scheduler is not supported with '
               'openmpi(>=3.0.0).')
+    conflicts('+cxx', when='@5:',
+              msg='C++ MPI bindings are removed in 5.0.X release')
+    conflicts('+cxx_exceptions', when='@5:',
+              msg='C++ exceptions are removed in 5.0.X release')
 
     filter_compiler_wrappers('openmpi/*-wrapper-data*', relative_root='share')
     conflicts('fabrics=libfabric', when='@:1.8')  # libfabric support was added in 1.10.0
@@ -431,10 +436,6 @@ class Openmpi(AutotoolsPackage):
             config_args.append('--enable-static')
             config_args.extend(self.with_or_without('pmi'))
 
-        if spec.satisfies('@2.0:'):
-            # for Open-MPI 2.0:, C++ bindings are disabled by default.
-            config_args.extend(['--enable-mpi-cxx'])
-
         if spec.satisfies('@3.0.0:', strict=True):
             config_args.append('--with-zlib={0}'.format(spec['zlib'].prefix))
 
@@ -532,10 +533,17 @@ class Openmpi(AutotoolsPackage):
             else:
                 config_args.append('--without-cuda')
 
-        if '+cxx_exceptions' in spec:
-            config_args.append('--enable-cxx-exceptions')
-        else:
-            config_args.append('--disable-cxx-exceptions')
+        if spec.satisfies('@:4'):
+            if '+cxx' in spec:
+                config_args.append('--enable-mpi-cxx')
+            else:
+                config_args.append('--disable-mpi-cxx')
+
+            if '+cxx_exceptions' in spec:
+                config_args.append('--enable-cxx-exceptions')
+            else:
+                config_args.append('--disable-cxx-exceptions')
+
         return config_args
 
     @run_after('install')