Force to use spawn for multiprocessing

Author: ronin-gw

PyMaSC/__init__.py

@@ -12,12 +12,15 @@
 import logging
 import sys
 import traceback
+import multiprocessing
 from functools import wraps
 from typing import Any, Callable
 
 VERSION = "0.3.1"
 WEBSITE_URL = "https://pymasc.sb.ecei.tohoku.ac.jp/"
 
+logger = logging.getLogger(__name__)
+
 
 def logging_version(logger: Any) -> None:
     """Log PyMaSC and Python version information.
@@ -34,6 +37,22 @@ def logging_version(logger: Any) -> None:
         logger.debug(line)
 
 
+def _ensure_spawn() -> None:
+    """Ensure the multiprocessing start method is set to `spawn`."""
+    try:
+        current = multiprocessing.get_start_method(allow_none=True)
+    except TypeError:
+        current = None
+    if current != "spawn":
+        try:
+            multiprocessing.set_start_method("spawn")
+        except RuntimeError:
+            logger.warning(
+                "Failed to set multiprocessing start method to 'spawn'. "
+                "This may cause issues with multiprocessing in PyMaSC."
+            )
+
+
 def entrypoint(logger: Any) -> Callable[[Callable[[], None]], Callable[[], None]]:
     """Decorator for main entry point exception handling.
 
@@ -57,6 +76,7 @@ def _entrypoint_wrapper_base(main_func: Callable[[], None]) -> Callable[[], None
         @wraps(main_func)
         def _inner() -> None:
             try:
+                _ensure_spawn()
                 main_func()
                 logger.info("PyMASC finished.")
             except KeyboardInterrupt: