Checklist

• I am confident this is a bug in CPython, not a bug in a third-party project
• I have searched theCPython issue tracker,
  and am confident this bug has not been reported before

CPython versions tested on:

3.10

Operating systems tested on:

Linux

Output from running 'python -VV' on the command line:

Python 3.10.12 (main, Jul 5 2023, 18:54:27) [GCC 11.2.0]

A clear and concise description of the bug:

The code forset_forkserver_preload (also in the latestmain branch) should check the type of the elements passed through themodule_names parameter, but instead checks the elements ofself._preload_modules.

Code for reproducing:

#!/usr/bin/env python3importmultiprocessingasmpimporttimedefwork(param):print("work")if__name__=='__main__':ctx=mp.get_context('forkserver')ctx.set_forkserver_preload(['time',1])withctx.Pool(2)asp:p.map(work, [0,1,2,3 ])

Raises error:

Traceback (most recent call last):  File "<string>", line 1, in <module>  File ".../lib/python3.10/multiprocessing/forkserver.py", line 178, in main    __import__(modname)TypeError: __import__() argument 1 must be str, not int

Linked PRs

• gh-107963: Fix set_forkserver_preload to check the type of given list #107965
• [3.12] gh-107963: Fix set_forkserver_preload to check the type of given list (GH-107965) #107975
• [3.11] gh-107963: Fix set_forkserver_preload to check the type of given list (GH-107965) #107976