`xeus` Python kernel is currently not supported (hence hidden)

Environment data

• VS Code version: 1.55.1
• Jupyter Extension version: v2021.5.702919634
• Python Extension version: v2021.3.680753044
• Windows 10
• Anaconda version: 4.10
• Type of virtual environment used: conda
• Jupyter server running: Local

Expected behaviour

Start Interactive Window to run cells (#%%) within VSC

Worked fine until last VSC update

Actual behaviour

Interactive Window fails to start

Unsupported KernelSpec file. args must be [, '-m', , arg1, arg2, ..]. Provied C:/Users/Steffen/Anaconda3/Library/bin/xpython --ip=127.0.0.1 --stdin=9092 --control=9090 --hb=9089 --Session.signature_scheme="hmac-sha256" --Session.key=b"baa190ae-91cc-46bd-84e8-f36673c6ec37" --shell=9091 --transport="tcp" --iopub=9093 --f=C:\Users\Steffen\AppData\Local\Temp\tmp-15216aFf72oCC3gGk.json

[claudiaregio]

Hi @steffenhennig I am unable to reproduce at this time. Could you provide all the logs when this issue occurs?
Terminal -> New Terminal -> Outputs -> Jupyter (please be sure to clear the outputs by clicking on the button I've circled to the right and make sure the following underlined items match). Reproduce the issue and please attach the logs to help us troubleshoot a bit further

Errors from log-file below:

Error 2021-04-20 11:01:19: Launching kernel daemon, Class name = h, completed in 837ms, has a falsy return value, Arg 1: Uri:c:\Users\Steffen\xyz\Untitled-1.ipynb, Arg 2: "c:\Users\Steffen\xyz", Arg 3: {"specFile":"C:\Users\Steffen\Anaconda3\share\jupyter\kernels\xpython\kernel.json","interpreterPath":"C:\Users\Steffen\Anaconda3\python.exe","name":"python385jvsc74a57bd0d406764cf7b946f86536b69511a8b6f70f1dfb17940e02446b1a7c3a63b579ac","argv":["C:/Users/Steffen/Anaconda3/Library/bin/xpython","--ip=127.0.0.1","--stdin=9003","--control=9001","--hb=9000","--Session.signature_scheme="hmac-sha256"","--Session.key=b"05c116d5-e987-42a9-a0a0-b71160cd874d"","--shell=9002","--transport="tcp"","--iopub=9004","--f=C:\Users\Steffen\AppData\Local\Temp\tmp-3236MGQQRjQZz5ti.json"],"language":"python","path":"C:/Users/Steffen/Anaconda3/Library/bin/xpython","display_name":"Python 3.8.5 64-bit (conda)","metadata":{"debugger":true}}, Arg 4: {"architecture":3,"path":"C:\Users\Steffen\Anaconda3\python.exe","version":{"options":{"loose":false,"includePrerelease":false},"loose":false,"raw":"3.8.5-final","major":3,"minor":8,"patch":5,"prerelease":["final"],"build":[],"version":"3.8.5-final"},"sysVersion":"3.8.5 (default, Sep 3 2020, 21:29:08) [MSC v.1916 64 bit (AMD64)]","sysPrefix":"C:\Users\Steffen\Anaconda3","fileHash":"dc146f2ba95052ed212bdaf2a1ecbf7e1fa194db7a049415c412a70a027d26e1a7d487b8e941f391f32bb8f556cd5b1810e4619d6c73d23aba0331c24cd9bc41","companyDisplayName":"Anaconda, Inc.","envType":"Conda","cachedEntry":true,"displayName":"Python 3.8.5 64-bit (conda)"}, Return Value: undefined [Error: Unsupported KernelSpec file. args must be [, '-m', , arg1, arg2, ..]. Provied C:/Users/Steffen/Anaconda3/Library/bin/xpython --ip=127.0.0.1 --stdin=9003 --control=9001 --hb=9000 --Session.signature_scheme="hmac-sha256" --Session.key=b"05c116d5-e987-42a9-a0a0-b71160cd874d" --shell=9002 --transport="tcp" --iopub=9004 --f=C:\Users\Steffen\AppData\Local\Temp\tmp-3236MGQQRjQZz5ti.json
at h.launch (c:\Users\Steffen.vscode\extensions\ms-toolsai.jupyter-2021.5.745244803\out\client\extension.js:47:797283)
at runNextTicks (internal/process/task_queues.js:62:5)
at processImmediate (internal/timers.js:429:9)]
Error 2021-04-20 11:01:19: Launching kernel in kernelProcess.ts, Class name = _, completed in 839ms, has a falsy return value, Arg 1: "c:\Users\Steffen\xyz", Return Value: undefined [Error: Unsupported KernelSpec file. args must be [, '-m', , arg1, arg2, ..]. Provied C:/Users/Steffen/Anaconda3/Library/bin/xpython --ip=127.0.0.1 --stdin=9003 --control=9001 --hb=9000 --Session.signature_scheme="hmac-sha256" --Session.key=b"05c116d5-e987-42a9-a0a0-b71160cd874d" --shell=9002 --transport="tcp" --iopub=9004 --f=C:\Users\Steffen\AppData\Local\Temp\tmp-3236MGQQRjQZz5ti.json
at h.launch (c:\Users\Steffen.vscode\extensions\ms-toolsai.jupyter-2021.5.745244803\out\client\extension.js:47:797283)
at runNextTicks (internal/process/task_queues.js:62:5)
at processImmediate (internal/timers.js:429:9)]
Error 2021-04-20 11:01:19: Failed to connect raw kernel session: Error: Unsupported KernelSpec file. args must be [, '-m', , arg1, arg2, ..]. Provied C:/Users/Steffen/Anaconda3/Library/bin/xpython --ip=127.0.0.1 --stdin=9003 --control=9001 --hb=9000 --Session.signature_scheme="hmac-sha256" --Session.key=b"05c116d5-e987-42a9-a0a0-b71160cd874d" --shell=9002 --transport="tcp" --iopub=9004 --f=C:\Users\Steffen\AppData\Local\Temp\tmp-3236MGQQRjQZz5ti.json
Info 2021-04-20 11:01:19: Shutdown session -- complete
Error 2021-04-20 11:01:19: Failed to determine if a notebook is active for the current editor [Error: Unsupported KernelSpec file. args must be [, '-m', , arg1, arg2, ..]. Provied C:/Users/Steffen/Anaconda3/Library/bin/xpython --ip=127.0.0.1 --stdin=9003 --control=9001 --hb=9000 --Session.signature_scheme="hmac-sha256" --Session.key=b"05c116d5-e987-42a9-a0a0-b71160cd874d" --shell=9002 --transport="tcp" --iopub=9004 --f=C:\Users\Steffen\AppData\Local\Temp\tmp-3236MGQQRjQZz5ti.json
at h.launch (c:\Users\Steffen.vscode\extensions\ms-toolsai.jupyter-2021.5.745244803\out\client\extension.js:47:797283)
at runNextTicks (internal/process/task_queues.js:62:5)
at processImmediate (internal/timers.js:429:9)]
Error 2021-04-20 11:01:19: DataScience Error [Error: Unsupported KernelSpec file. args must be [, '-m', , arg1, arg2, ..]. Provied C:/Users/Steffen/Anaconda3/Library/bin/xpython --ip=127.0.0.1 --stdin=9003 --control=9001 --hb=9000 --Session.signature_scheme="hmac-sha256" --Session.key=b"05c116d5-e987-42a9-a0a0-b71160cd874d" --shell=9002 --transport="tcp" --iopub=9004 --f=C:\Users\Steffen\AppData\Local\Temp\tmp-3236MGQQRjQZz5ti.json
at h.launch (c:\Users\Steffen.vscode\extensions\ms-toolsai.jupyter-2021.5.745244803\out\client\extension.js:47:797283)
at runNextTicks (internal/process/task_queues.js:62:5)
at processImmediate (internal/timers.js:429:9)]

Thanks for your help

[DonJayamanne]

Oh you seem to be using the xeus kernel
Please could you confirm that.

After uninstalling xeus the problem disappears. Thanks.

[DonJayamanne]

I'll keep this issue open, basically we need to ensure we do not treat xeus kernel as a Python kernel (that can be started using python code).