Ensure HOME env variable is always set (mandatory for OpenMPI 5+)

If it is missing the value of KHIOPS_MPI_HOME is copied

Author: Thierry RAMORASOAVINA

khiops/core/internals/runner.py

@@ -994,8 +994,12 @@ def _initialize_khiops_environment(self):
                     var_value = ""
                 else:
                     continue
+
+                if var_name == "KHIOPS_MPI_HOME":
+                    # Override HOME for OpenMPI 5+
+                    os.environ["HOME"] = var_value
                 # Set paths to Khiops binaries
-                if var_name == "KHIOPS_PATH":
+                elif var_name == "KHIOPS_PATH":
                     self.khiops_path = var_value
                     os.environ["KHIOPS_PATH"] = var_value
                 elif var_name == "KHIOPS_COCLUSTERING_PATH":

tests/test_khiops_integrations.py

@@ -288,6 +288,12 @@ def test_runner_environment_initialization(self):
         .. note::
             To test a real initialization this test should be executed alone.
         """
+
+        # Unset HOME to test the automatic fix for OpenMPI 5+
+        # when initializing the KhiopsLocalRunner environment
+        if os.environ.get("KHIOPS_MPI_HOME") is not None:
+            del os.environ["HOME"]
+
         # Obtain the current runner
         runner = kh.get_runner()
 
@@ -304,6 +310,9 @@ def test_runner_environment_initialization(self):
             self.assertTrue(os.path.isfile(mpiexec_path))
             self.assertTrue(os.access(mpiexec_path, os.X_OK))
 
+        # Check `HOME` is always set (required for OpenMPI 5+)
+        self.assertIsNotNone(os.environ.get("HOME"))
+
         # Check that runner creation sets `KHIOPS_API_MODE` to `true`
         # Store original KHIOPS_API_MODE if any, then delete it from the
         # environment if present