multiprocessing.spawn submodule and multiprocessing.pool stubs (#2823)

Added stub for multiprocessing.spawn submodule and updated multiprocessing.pool stub

Closes #2758

stdlib/3/multiprocessing/__init__.pyi

@@ -6,13 +6,16 @@ from typing import (
 )
 
 from logging import Logger
-from multiprocessing import connection, pool, synchronize
+from multiprocessing import connection, pool, spawn, synchronize
 from multiprocessing.context import (
     BaseContext,
     ProcessError as ProcessError, BufferTooShort as BufferTooShort, TimeoutError as TimeoutError, AuthenticationError as AuthenticationError)
 from multiprocessing.managers import SyncManager
 from multiprocessing.process import current_process as current_process
 from multiprocessing.queues import Queue as Queue, SimpleQueue as SimpleQueue, JoinableQueue as JoinableQueue
+from multiprocessing.spawn import freeze_support as freeze_support
+from multiprocessing.spawn import set_executable as set_executable
+
 import sys
 
 # N.B. The functions below are generated at runtime by partially applying
@@ -71,12 +74,10 @@ class Value():
 def active_children() -> List[Process]: ...
 def allow_connection_pickling() -> None: ...
 def cpu_count() -> int: ...
-def freeze_support() -> None: ...
 def get_logger() -> Logger: ...
 def log_to_stderr(level: Optional[Union[str, int]] = ...) -> Logger: ...
 def Manager() -> SyncManager: ...
 def set_forkserver_preload(module_names: List[str]) -> None: ...
-def set_executable(executable: str) -> None: ...
 def get_all_start_methods() -> List[str]: ...
 def get_context(method: Optional[str] = ...) -> BaseContext: ...
 def get_start_method(allow_none: Optional[bool]) -> Optional[str]: ...

stdlib/3/multiprocessing/pool.pyi

@@ -1,18 +1,22 @@
 from typing import (
     Any, Callable, ContextManager, Iterable, Mapping, Optional, List,
-    TypeVar, Generic, Iterator
+    Type, TypeVar, Generic, Iterator
 )
+from types import TracebackType
 
 _PT = TypeVar('_PT', bound='Pool')
 _S = TypeVar('_S')
 _T = TypeVar('_T')
 
-class AsyncResult(Generic[_T]):
+class ApplyResult(Generic[_T]):
     def get(self, timeout: Optional[float] = ...) -> _T: ...
     def wait(self, timeout: Optional[float] = ...) -> None: ...
     def ready(self) -> bool: ...
     def successful(self) -> bool: ...
 
+# alias created during issue #17805
+AsyncResult = ApplyResult
+
 _IMIT = TypeVar('_IMIT', bound=IMapIterator)
 
 class IMapIterator(Iterator[_T]):
@@ -76,3 +80,8 @@ class ThreadPool(Pool, ContextManager[ThreadPool]):
     def __init__(self, processes: Optional[int] = ...,
                  initializer: Optional[Callable[..., Any]] = ...,
                  initargs: Iterable[Any] = ...) -> None: ...
+
+# undocumented
+RUN: int
+CLOSE: int
+TERMINATE: int

stdlib/3/multiprocessing/spawn.pyi

@@ -0,0 +1,18 @@
+from typing import Any, Dict, List, Mapping, Optional, Sequence
+from types import ModuleType
+
+WINEXE: bool
+WINSERVICE: bool
+
+def set_executable(exe: str) -> None: ...
+def get_executable() -> str: ...
+def is_forking(argv: Sequence[str]) -> bool: ...
+def freeze_support() -> None: ...
+def get_command_line(**kwds: Any) -> List[str]: ...
+def spawn_main(pipe_handle: int, parent_pid: Optional[int] = ..., tracker_fd: Optional[int] = ...) -> None: ...
+# undocumented
+def _main(fd: int) -> Any: ...
+def get_preparation_data(name: str) -> Dict[str, Any]: ...
+old_main_modules: List[ModuleType] = ...
+def prepare(data: Mapping[str, Any]) -> None: ...
+def import_main_path(main_path: str) -> None: ...