ipykernel
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Published
20 hours ago •
ipython
ipython
subprocess stdout capture does not seem to work on Windows
ipykernel is capturing stdout from subprocesses since ipykernel 6.0.0 according to the changelog.
On Windows it does not seem like the output of subprocesses is correctly captured. Here is a snippet to reproduce:
This came up in https://github.com/scikit-learn/scikit-learn/issues/22849#issuecomment-1068947522.
from concurrent.futures import ProcessPoolExecutor
# write local module since on Windows you can not use interactively defined functions in ProcessPoolExecutor
with open('func.py', 'w') as f:
f.write('def func(arg): print("from subprocess, arg:", arg)')
from func import func
executor = ProcessPoolExecutor(max_workers=2)
future = executor.submit(func, 1)
future.result()
On Linux (output from the subprocess is visible)
On Windows (no output from the subprocess):
Windows environment details
# packages in environment at C:\Users\lesteve\mambaforge\envs\test:
#
# Name Version Build Channel
argon2-cffi 21.3.0 pyhd8ed1ab_0 conda-forge
argon2-cffi-bindings 21.2.0 py310he2412df_1 conda-forge
asttokens 2.0.5 pyhd8ed1ab_0 conda-forge
attrs 21.4.0 pyhd8ed1ab_0 conda-forge
backcall 0.2.0 pyh9f0ad1d_0 conda-forge
backports 1.0 py_2 conda-forge
backports.functools_lru_cache 1.6.4 pyhd8ed1ab_0 conda-forge
beautifulsoup4 4.10.0 pyha770c72_0 conda-forge
bleach 4.1.0 pyhd8ed1ab_0 conda-forge
bzip2 1.0.8 h8ffe710_4 conda-forge
ca-certificates 2021.10.8 h5b45459_0 conda-forge
cffi 1.15.0 py310hcbf9ad4_0 conda-forge
colorama 0.4.4 pyh9f0ad1d_0 conda-forge
debugpy 1.5.1 py310h8a704f9_0 conda-forge
decorator 5.1.1 pyhd8ed1ab_0 conda-forge
defusedxml 0.7.1 pyhd8ed1ab_0 conda-forge
entrypoints 0.4 pyhd8ed1ab_0 conda-forge
executing 0.8.3 pyhd8ed1ab_0 conda-forge
flit-core 3.7.1 pyhd8ed1ab_0 conda-forge
icu 68.2 h0e60522_0 conda-forge
importlib-metadata 4.11.3 py310h5588dad_0 conda-forge
importlib_resources 5.4.0 pyhd8ed1ab_0 conda-forge
ipykernel 6.9.2 py310hbbfc1a7_0 conda-forge
ipython 8.1.1 py310h5588dad_0 conda-forge
ipython_genutils 0.2.0 py_1 conda-forge
ipywidgets 7.6.5 pyhd8ed1ab_0 conda-forge
jedi 0.18.1 py310h5588dad_0 conda-forge
jinja2 3.0.3 pyhd8ed1ab_0 conda-forge
jpeg 9e h8ffe710_0 conda-forge
jsonschema 4.4.0 pyhd8ed1ab_0 conda-forge
jupyter 1.0.0 py310h5588dad_7 conda-forge
jupyter_client 7.1.2 pyhd8ed1ab_0 conda-forge
jupyter_console 6.4.3 pyhd8ed1ab_0 conda-forge
jupyter_core 4.9.2 py310h5588dad_0 conda-forge
jupyterlab_pygments 0.1.2 pyh9f0ad1d_0 conda-forge
jupyterlab_widgets 1.0.2 pyhd8ed1ab_0 conda-forge
libclang 11.1.0 default_h5c34c98_1 conda-forge
libffi 3.4.2 h8ffe710_5 conda-forge
libpng 1.6.37 h1d00b33_2 conda-forge
libsodium 1.0.18 h8d14728_1 conda-forge
libzlib 1.2.11 h8ffe710_1013 conda-forge
markupsafe 2.1.1 py310he2412df_0 conda-forge
matplotlib-inline 0.1.3 pyhd8ed1ab_0 conda-forge
mistune 0.8.4 py310he2412df_1005 conda-forge
nbclient 0.5.13 pyhd8ed1ab_0 conda-forge
nbconvert 6.4.4 py310h5588dad_0 conda-forge
nbformat 5.2.0 pyhd8ed1ab_0 conda-forge
nest-asyncio 1.5.4 pyhd8ed1ab_0 conda-forge
notebook 6.4.10 pyha770c72_0 conda-forge
openssl 1.1.1l h8ffe710_0 conda-forge
packaging 21.3 pyhd8ed1ab_0 conda-forge
pandoc 2.17.1.1 h57928b3_0 conda-forge
pandocfilters 1.5.0 pyhd8ed1ab_0 conda-forge
parso 0.8.3 pyhd8ed1ab_0 conda-forge
pickleshare 0.7.5 py_1003 conda-forge
pip 22.0.4 pyhd8ed1ab_0 conda-forge
prometheus_client 0.13.1 pyhd8ed1ab_0 conda-forge
prompt-toolkit 3.0.27 pyha770c72_0 conda-forge
prompt_toolkit 3.0.27 hd8ed1ab_0 conda-forge
psutil 5.9.0 py310he2412df_0 conda-forge
pure_eval 0.2.2 pyhd8ed1ab_0 conda-forge
pycparser 2.21 pyhd8ed1ab_0 conda-forge
pygments 2.11.2 pyhd8ed1ab_0 conda-forge
pyparsing 3.0.7 pyhd8ed1ab_0 conda-forge
pyqt 5.12.3 py310h5588dad_8 conda-forge
pyqt-impl 5.12.3 py310h8a704f9_8 conda-forge
pyqt5-sip 4.19.18 py310h8a704f9_8 conda-forge
pyqtchart 5.12 py310h8a704f9_8 conda-forge
pyqtwebengine 5.12.1 py310h8a704f9_8 conda-forge
pyrsistent 0.18.1 py310he2412df_0 conda-forge
python 3.10.2 h9a09f29_4_cpython conda-forge
python-dateutil 2.8.2 pyhd8ed1ab_0 conda-forge
python_abi 3.10 2_cp310 conda-forge
pywin32 303 py310he2412df_0 conda-forge
pywinpty 2.0.5 py310h00ffb61_0 conda-forge
pyzmq 22.3.0 py310h73ada01_1 conda-forge
qt 5.12.9 h5909a2a_4 conda-forge
qtconsole 5.2.2 pyhd8ed1ab_1 conda-forge
qtconsole-base 5.2.2 pyhd8ed1ab_1 conda-forge
qtpy 2.0.1 pyhd8ed1ab_0 conda-forge
send2trash 1.8.0 pyhd8ed1ab_0 conda-forge
setuptools 60.9.3 py310h5588dad_0 conda-forge
six 1.16.0 pyh6c4a22f_0 conda-forge
soupsieve 2.3.1 pyhd8ed1ab_0 conda-forge
sqlite 3.37.1 h8ffe710_0 conda-forge
stack_data 0.2.0 pyhd8ed1ab_0 conda-forge
terminado 0.13.3 py310h5588dad_0 conda-forge
testpath 0.6.0 pyhd8ed1ab_0 conda-forge
tk 8.6.12 h8ffe710_0 conda-forge
tornado 6.1 py310he2412df_2 conda-forge
traitlets 5.1.1 pyhd8ed1ab_0 conda-forge
tzdata 2021e he74cb21_0 conda-forge
ucrt 10.0.20348.0 h57928b3_0 conda-forge
vc 14.2 hb210afc_6 conda-forge
vs2015_runtime 14.29.30037 h902a5da_6 conda-forge
wcwidth 0.2.5 pyh9f0ad1d_2 conda-forge
webencodings 0.5.1 py_1 conda-forge
wheel 0.37.1 pyhd8ed1ab_0 conda-forge
widgetsnbextension 3.5.2 py310h5588dad_1 conda-forge
winpty 0.4.3 4 conda-forge
xz 5.2.5 h62dcd97_1 conda-forge
zeromq 4.3.4 h0e60522_1 conda-forge
zipp 3.7.0 pyhd8ed1ab_1 conda-forge
zlib 1.2.11 h8ffe710_1013 conda-forge
Yes, it should specify that the feature is only for posix systems. The approach to output capture doesn't work on Windows yet.
OK thanks, I have opened https://github.com/ipython/ipykernel/pull/883 to mention this in the changelog