Print in multiprocessing.Process crashing the engine about ipyparallel

[minrk]

More info would help, because the given example doesn't work for other reasons for me:

AttributeError: Can't get attribute 'foo' on <module '__main__' (built-in)>

but if I change it to p = Process(target=print, args=(42,)) to avoid looking up foo in nonexistent __main__, then I see:

[stdout:0] 42

and no errors.

Can you share the output of pip freeze and Python version, OS?

[Nimrod0901]

Thanks for reply!

Process(target=print, args=(42, )) also gives me the same error msg.
Also, I tested it in non-interactive environment, the problem still occured.

Python version: 3.8.10 (GCC 9.4.0)
OS: Ubuntu 20.04.4 LTS
Due to the network limitation, I can't show you the full output of pip freeze but some maybe revelant.

ipyparallel==8.6.1
jupyter==1.0.0
jupyter-client==7.3.5
jupyter-core==4.11.1

[minrk]

The most relevant additional packages are ipython and ipykernel.

[minrk]

When I run this in an empty ubuntu 20:04 container, I don't get the captured output, but I also don't get any errors:

# pip freeze
asttokens==2.4.0
backcall==0.2.0
comm==0.1.4
debugpy==1.7.0
decorator==5.1.1
entrypoints==0.4
executing==1.2.0
importlib-metadata==6.8.0
ipykernel==6.25.2
ipyparallel==8.6.1
ipython==8.12.2
jedi==0.19.0
jupyter_client==8.3.1
jupyter_core==5.3.1
matplotlib-inline==0.1.6
nest-asyncio==1.5.7
packaging==23.1
parso==0.8.3
pexpect==4.8.0
pickleshare==0.7.5
platformdirs==3.10.0
prompt-toolkit==3.0.39
psutil==5.9.5
ptyprocess==0.7.0
pure-eval==0.2.2
Pygments==2.16.1
python-dateutil==2.8.2
pyzmq==25.1.1
six==1.16.0
stack-data==0.6.2
tornado==6.3.3
tqdm==4.66.1
traitlets==5.9.0
typing_extensions==4.7.1
wcwidth==0.2.6
zipp==3.16.2

[Nimrod0901]

ipykernel==6.16.0
ipyparallel==8.6.1
ipython==8.5.0
ipython-genutils==0.2.0
ipywidgets==8.0.2

Hope this help

[minrk]

Try upgrading ipykernel and ipython. ipykernel is the package most likely to be relevant.

[Nimrod0901]

Upgrading ipykernel and ipython doesn't work, but upgrading pyzmq does fix this problem. 24.0.1 -> 25.1.1

Since it's not a issue of ipyparallel, I'll close it. Thanks for your patience.