Python Multiprocessing error: AttributeError: module '__main__' has no attribute '__spec__'

user_8474060 0
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I'm using Python 3.6 and am trying to follow along with the very first example at the website below (full code also below) and am getting the below error: https://docs.python.org/3.6/library/multiprocessing.html

Error message: AttributeError: module '__main__' has no attribute '__spec__'

Full example code:

from multiprocessing import Pool

def f(x):
    return x*x

if __name__ == '__main__':
    with Pool(5) as p:
        print(p.map(f, [1, 2, 3]))

I tried Googling it and searching Stack Overflow but I've only found one other case of this error and it did not have an answer.

spyder python-multiprocessing multiprocessing python
4 Answers

pdb users

The question didn't specifically mention Spyder nor Conda (though it is tagged as such). Hence, I will note that I found this can also happen when using pdb.

E.g.

python -m pdb myprogram.py

Passing __spec__ = None would be a useful workaround if you wanted to persist with pdb.

user_13354730

the same probelm in Spyder (Anaconda3, python 3.6) when I try the external terminal.

Error message: AttributeError: module '__main__' has no attribute '__spec__'

I changed the Run console to 'Excute in current console', and applied it. then if that doesnot work, try other conselor and then change back to 'Excute in current console'. Finally, it works. no '__spec__ = None' is needed.

user_105529750

Same problem with Spyder (Anaconda3, python 3.7).

I used

from genetic_selection import GeneticSelectionCV

def main(): .... and as I was running the code, an error like this occured:

main_mod_name = getattr(main_module.__spec__, "name", None)

AttributeError: module '__main__' has no attribute '__spec__'

what I did is deleted "__spec__" in main_mod_name = getattr(main_module.__spec__, "name", None)

so I only have this: main_mod_name = getattr(main_module, "name", None)

the code then worked perfectly fine.

user_144596770
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