Ensure HOME is always set when running khiops core with OpenMPI 5+

- A specific environment is created when running khiops core. In this environment HOME is set using KHIOPS_MPI_HOME if it exists

Author: Thierry RAMORASOAVINA

khiops/core/internals/runner.py

@@ -994,8 +994,14 @@ def _initialize_khiops_environment(self):
                     var_value = ""
                 else:
                     continue
+
+                # Special var to export in order
+                # to prepend to or to set to HOME for OpenMPI 5+
+                # when running khiops core
+                if var_name == "KHIOPS_MPI_HOME":
+                    os.environ["KHIOPS_MPI_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":
@@ -1443,6 +1449,14 @@ def raw_run(self, tool_name, command_line_args=None, use_mpi=True, trace=False):
                     khiops_call += f" {quote}{arg}{quote}"
             print(f"Khiops execution call: {khiops_call}")
 
+        # Build custom Khiops process environment
+        # which makes sure HOME is defined and set
+        # according to khiops_env's KHIOPS_MPI_HOME
+        khiops_env = os.environ.copy()
+        khiops_env["HOME"] = os.path.pathsep.join(
+            [khiops_env.get("KHIOPS_MPI_HOME", ""), khiops_env.get("HOME", "")]
+        )
+
         # Execute the process
         with subprocess.Popen(
             khiops_process_args,
@@ -1452,6 +1466,7 @@ def raw_run(self, tool_name, command_line_args=None, use_mpi=True, trace=False):
             encoding="utf8",
             errors="replace",
             universal_newlines=True,
+            env=khiops_env,
         ) as khiops_process:
             stdout, stderr = khiops_process.communicate()
 

tests/test_khiops_integrations.py

@@ -282,12 +282,85 @@ def test_environment_error_on_bogus_khiops_env_script(self):
         output_msg = str(context.exception)
         self.assertEqual(output_msg, expected_msg)
 
+    def test_runner_environment_for_openmpi5(self):
+        """Test if HOME is actually corrected for OpenMPI 5+"""
+
+        with tempfile.TemporaryDirectory() as temp_dir:
+
+            # Create temporary khiops_env binary dir
+            # Note: The "bin" subdir is needed for Windows.
+            temp_khiops_env_dir = os.path.join(temp_dir, "bin")
+            os.makedirs(temp_khiops_env_dir)
+
+            # Create temporary khiops_env path
+            temp_khiops_env_file_path = os.path.join(temp_khiops_env_dir, "khiops_env")
+
+            # On Windows, set KHIOPS_HOME to the temp dir
+            original_khiops_home_env_var = os.environ.get("KHIOPS_HOME")
+            if platform.system() == "Windows":
+                os.environ["KHIOPS_HOME"] = temp_dir
+                temp_khiops_env_file_path += ".cmd"
+
+            # Replace the khiops_env with a crafted one
+            with open(
+                temp_khiops_env_file_path, "w", encoding="utf-8"
+            ) as temp_khiops_env_file:
+                if platform.system() == "Windows":
+                    temp_khiops_env_file.write(
+                        "echo KHIOPS_PATH /usr/bin/MODL_openmpi\r\n"
+                    )
+                    temp_khiops_env_file.write(
+                        "echo KHIOPS_COCLUSTERING_PATH "
+                        "/usr/bin/MODL_Coclustering_openmpi\r\n"
+                    )
+                    temp_khiops_env_file.write("echo KHIOPS_MPI_HOME \tmp" + "\r\n")
+                else:
+                    temp_khiops_env_file.write("#!/bin/bash\n")
+                    temp_khiops_env_file.write(
+                        "echo KHIOPS_PATH /usr/bin/MODL_openmpi\n"
+                    )
+                    temp_khiops_env_file.write(
+                        "echo KHIOPS_COCLUSTERING_PATH "
+                        "/usr/bin/MODL_Coclustering_openmpi\n"
+                    )
+                    temp_khiops_env_file.write("echo KHIOPS_MPI_HOME /tmp\n")
+
+            # Make the temporary khiops_env file executable
+            os.chmod(
+                temp_khiops_env_file_path,
+                os.stat(temp_khiops_env_file_path).st_mode | stat.S_IEXEC,
+            )
+
+            # Store initial PATH
+            original_path_env_var = os.environ["PATH"]
+
+            # Prepend path to temporary khiops_env to PATH
+            os.environ["PATH"] = (
+                temp_khiops_env_dir + os.pathsep + original_path_env_var
+            )
+
+            _ = KhiopsLocalRunner()
+
+            # Check `KHIOPS_MPI_HOME` is correctly exported for OpenMPI 5+
+            self.assertIsNotNone(os.environ.get("KHIOPS_MPI_HOME"))
+
+            # Restore initial PATH
+            os.environ["PATH"] = original_path_env_var
+
+            # On Windows, restore initial KHIOPS_HOME
+            if (
+                platform.system() == "Windows"
+                and original_khiops_home_env_var is not None
+            ):
+                os.environ["KHIOPS_HOME"] = original_khiops_home_env_var
+
     def test_runner_environment_initialization(self):
         """Test that local runner initializes/ed its environment properly
 
         .. note::
             To test a real initialization this test should be executed alone.
         """
+
         # Obtain the current runner
         runner = kh.get_runner()