Use spawn context instead of default context for multiprocessing to f…

…ix issue on Linux [release]

src/datadreamer.py

@@ -2,7 +2,7 @@
 import logging
 import os
 from collections import UserDict, defaultdict
-from multiprocessing import Process
+from multiprocessing.context import SpawnProcess
 from threading import Lock
 from typing import TYPE_CHECKING, Any, Callable, cast
 
@@ -139,7 +139,7 @@ def _register_child_thread(parent_thread_id: tuple[int, int]):
             DataDreamer.ctx.step_stack[get_thread_id()] = []
 
     @staticmethod
-    def _add_process(process: Process):
+    def _add_process(process: SpawnProcess):
         DataDreamer.ctx.background_processes.append(process)
 
     @staticmethod

src/utils/background_utils.py

@@ -4,7 +4,8 @@
 from collections import UserDict, namedtuple
 from functools import partial
 from logging import Logger, StreamHandler
-from multiprocessing import Process, Queue, get_start_method, set_start_method
+from multiprocessing import get_context
+from multiprocessing.context import SpawnProcess
 from threading import Thread, get_ident
 from time import sleep, time
 from typing import Any, Callable, Generator
@@ -30,7 +31,7 @@ def get_parent_process_context() -> dict[str, Any]:
     from .. import DataDreamer
 
     # Remove non-picklable (and un-needed attrs from ctx)
-    ctx = UserDict()
+    ctx: Any = UserDict()
     ctx.__dict__.update(DataDreamer.ctx.__dict__.copy())
     if hasattr(ctx, "background_processes"):
         del ctx.background_processes
@@ -146,11 +147,12 @@ def run_in_background_thread(func: Callable, *args, **kwargs) -> Thread:
     return t
 
 
-def run_in_background_process(func: Callable, *args, **kwargs) -> tuple[Process, Any]:
-    pipe: Any = Queue(1)
-    orig_start_method = get_start_method()
-    set_start_method("spawn", force=True)
-    p = Process(
+def run_in_background_process(
+    func: Callable, *args, **kwargs
+) -> tuple[SpawnProcess, Any]:
+    spawn_context = get_context(method="spawn")
+    pipe: Any = spawn_context.Queue(1)
+    p = spawn_context.Process(
         target=partial(
             _process_func_wrapper,
             get_parent_process_context(),
@@ -161,7 +163,6 @@ def run_in_background_process(func: Callable, *args, **kwargs) -> tuple[Process,
     )
     p.daemon = False
     p.start()
-    set_start_method(orig_start_method, force=True)
     return p, pipe