Eric Snow <ericsnowcurren...@gmail.com> added the comment:
Yeah, the case of pickle + __main__ is an awkward one. [1] However, the approach taken by multiprocessing isn't the right one for subinterpreters. Multiprocessing operates under 2 design points that do not apply to subinterpreters: * every process is running in the same __main__ module (sans the "script" part) * pickle is a critical part of data-passing For spawn, multiprocessing automatically runs the original __main__ module in each newly spawned process. [2] Note that it runs it there with __name__ set to __mp_main__ (rather than __main__), to keep the "script" part from running. Subinterpreters could be made to work like this [3] but in reality they are more like processes created using the subprocess module. I do not expect that to change. However, there is room for add opt-in support for rerunning __main__ in a subinterpreter, or helpers to accomplish the same. We can address such opt-in support or helpers in a separate issue later. For now we are focusing on the fundamentals (at least in the context of PEP 554). [1] Note that the problem is only with the __main__ module. For other modules pickle does the right thing. [2] https://github.com/python/cpython/blob/master/Lib/multiprocessing/spawn.py#L287 [3] I expect we will see subinterpreters supported in the multiprocessing module just like threads are supported. ---------- _______________________________________ Python tracker <rep...@bugs.python.org> <https://bugs.python.org/issue37292> _______________________________________ _______________________________________________ Python-bugs-list mailing list Unsubscribe: https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
