Summary of Kernel Issues

[DonJayamanne]

Installing ipykernel or other dependencies

• Install pip when not detected when attempting to install ipykernel #7739
• Zeromq for Mac M1 & other linux distros  #5206
  • We have lots of issues with jupyter, using raw kernels should make installing jupyter unnecessary.
  • I.e. removes one flaky part completely
• Better handling of kernel crashes (dead kernels) #7846
• Better handling of failed ipykernel installations & ipykernel detection #7902
• IPyKernel doesn't install correctly when powershell is default #421
• Installing ipykernel requires admin on Windows #1253
• Failed to install IPyKernel on windows in PowerShell prompt due to permission error #8332
• Failure to activate conda env results in failure to detect if ipykernel is installed #8119
• ipykernel invalid install path with Git Bash, requires pressing cancel on a notification to start the install #8391
• Install kernel dependencies with the -U flag #4758
• IPyKernel not getting installed when re-creating the virtual environment #9135
• Wrong interpreter is used when installing ipykernel #9104
• Extension won't install ipykernel when it should be able to. #9133
• IPyKernel not getting installed when re-creating the virtual environment #9135

Start/Restart/Stop/Crahes

• No kernels available (see kernel enumeration)
• Slow Kernel startup/restart #7849
• Better handling of kernel crashes (dead kernels) #7846
  • Warn users when files override built in packages that could have caused the kernel to fail #7538
  • Prompt the user to restart the kernel when running a cell against a dead kernel #7399
  • Kernel issues with Python 2.7 #4680
  • Display warning when user selects outdated versions of Python #7960
  • Recommend renaming python file if python file it overwrites builtins #8195
• Is the kernel error being reported correct (i.e. the most useful?) #8060
• Provide a better error message when kernel dies #7318
• Display python error message when kernel dies #7646
• Unable to start kernel - Waiting for Jupiter Session to be Idle (Kernel fails to start as completions request crahes without sending a response back) #9014
• Kernel startup error messages should contain more information about what went wrong and how to resolve it #8354
• Display kernel startup failure messages in cell output #8351
• Can we deal with user code (packages) causing kernel failures #9375
• Performance improvements related to startup of Kernels #8352
• Slow Kernel startup/restart #7849
• No indication that kernel is starting when it's starting... #7134
• Activation and execution of cells is slower when using Conda Run #8580
• Packages are not imported from the selected Python environment #8553
• Kernelspecs with non-default arguments don't work. #7063
• Some kernels do a lot of processing on start so appear to be slow to start running cells #7952
• Failure to activate conda env results in failure to detect if ipykernel is installed #8119
• Can not use Wolfram Kernel when using Local Server #7334
• Cannot launch other kernels if the user folder has a space in the path. #4647
• Jupyter notebook starts with wrong kernel #6048
• Cannot run Cadabra2 kernel in vscode #6622
• {connection_file} argument not passed to Jupyter kernel  #7203
• Issue in R kernel, when more than one line exist in a cell #7472
• Cannot restart kernel after kernel dies  #7167
• 2 Python processes started per kernel when running a notebook #1462
• SageMath WSL2 kernel timed out #3977
• Trying to use old nonexistent kernel #1184
• Failed to change kernel [NoPermissions (FileSystemError): Unable to write file #5494
• IPyKernel not getting installed when re-creating the virtual environment #9135

Kernel Enumeration

• Return a default controller as fast as possible to enable run button on native notebooks #5861
  Fixes the following:
  • Slow to get list of interpreters (this was deferred a few months ago pending Python extension API, now its ready)
  • New Virtual environments not listed in Kernels until i reload VS Code #5319
  • Notebooks - Kernels Not Enumerated #7844
• getInterpretersList is picky about what virtual envs to return #7664
• Kernel specs with custom env variables not listed in list of kernel specs #7719
• Required to select kernels for each new notebook (everytime) #7851
• Jupyter notebooks not using Python in current path #5998
• Choosing from a list of possible notebook kernels is confusing compared to Jupyter #7373
• Sort kernel list based on usage (like MRU) #7374
• Identify kernels that have ipykernel installed to kernels picker. #7230
• Consider deleting our old kernelspecs #7171
• Allow user to pick the 'default' kernel when starting #6290
• When using remote, if the token has expired nothing works in Notebooks and no errors are displayed #8474
• Wrong kernel name in metadata kernelspec when using kernel from virtualenv #8796
• Kernels in kernel picker have the same name and do not use "display_name" field of kernelspec #8481
• Kernel specs with custom env variables not listed in list of kernel specs #7719
• New Virtual environments not listed in Kernels until i reload VS Code #5319
• Incorrect PYTHONPATH variable with .env file with relative paths #5061
• Can't see or select Jupyter kernel's from Kernel drop-down #7706
• When using Jupyter (instead of raw kernels) create Kernelspecs in a custom directory #9141

Wiki/troubleshotting for all of the above

• Update Wiki with troubleshooting guide for Kernel & IPyKernel issues #5291

Codespaces

• Unresolved ipykernel installation - codespaces #4244

Kernel Doctor (#5150)

• Fixes the following:
• Notebooks - General Kernel Start Failure #7845
• Suggestion: Kernel Doctor - notebook for diagnosing kernel problems #5150

Remote

• Kernels not being listed
• Opening a notebook on remote, closing it, and reopening it does not reuse the same kernel #7610
• Pointing to a non running remote server makes kernel picker and run cell disappear #6297
• Interpreter picker seems to be displayed in Jupyter remote scenario #6247
• When connecting to remote connection, if the default kernel doesn't start, then remote will never work in vscode #7384
• Remote kernels forces notebook to hide run & kernel buttons when disconnected #7796
• Can't change remote Jupyter server without restarting VS Code #1367
• When using remote, if the token has expired nothing works in Notebooks and no errors are displayed #8474
• Opening a notebook on remote, closing it, and reopening it does not reuse the same kernel #7610
• When connecting to remote connection, if the default kernel doesn't start, then remote will never work in vscode #7384

Review
#1122

Misc

• Shell commands such as !pip !python !where python do not point to the right executable #9089
• Jupyter Notebook does not execute !python or %run in the selected conda environment. #4682
• interpreter name in kernelspec gets jumbed to python3<hash #> #5612
• %matplotlib QT5 doesn't work  #8322
• VSCode leaves several running processes after exit #1626
• Autocomplete hangs the kernel for interactive window #1300
• !pip not installing packages as expected #6864
• Incorrect Jupyter notebookFileRoot when workspace has more than one folder #8561
• Autocomplete hangs the kernel for interactive window #1300
• Kernel interrupt not working when interrupt mode is message (Julia on windows) #3927
• Issues with activation of Conda environments #9254
• Kernel issues related to login shells #9682

Quirks

• Completions request crahses and kernel does not handle this (hence no response is sent back) Unable to start kernel - Waiting for Jupiter Session to be Idle (Kernel fails to start as completions request crahes without sending a response back) #9014
• Interrupting Python kernel on windows requires special code
• Zmq doesn't work on Mac M1 (Apple Chips)
• Jupyter doesn't start with CLI but starts with daemon
  • Slow Kernel startup/restart #7849
  • Cause is still unknown (WIP)
• Using latest versions of Python with Jupyter, Conda, etc
  • Takes a while for packages to catchup Connecting to kernel for python 3.10.0 failed #8944

[DonJayamanne]

For Nov 2021:

• Install pip when not detected when attempting to install ipykernel #7739
• Display warning when user selects outdated versions of Python #7960
• !pip not installing packages as expected #6864
• Recommend renaming python file if python file it overwrites builtins #8195
• Better handling of failed ipykernel installations & ipykernel detection #7902
• Slow Kernel startup/restart #7849
• Failure to activate conda env results in failure to detect if ipykernel is installed #8119

Telemetry

• Kernel specs with custom env variables not listed in list of kernel specs #7719
• Need telemetry to check if anybody is using two notebooks with different kernels at the same time #7376
• Track import and possibly other 'errors' as kernel crashes #8122
• Recommend renaming python file if python file it overwrites builtins #8195

[DonJayamanne]

Closing this issue as completed, all that is pending in distribution of zmq and 2 items related to selecting the right python env from the kernel picker.