Always use LF instead of CRLF for *.ipynb files regardless of platform and when sending code to the kernel

Environment data

• VS Code version: 1.53.0-insider (2021-01-29T05:13:48.533Z)
• Jupyter Extension version (available under the Extensions sidebar): v2020.12.414227025
• Python Extension version (available under the Extensions sidebar): 2021.2.518958983-dev
• OS (Windows | Mac | Linux distro) and version: Windows 10
• Python and/or Anaconda version: Python 3.8.5 using Anaconda
• Type of virtual environment used (N/A | venv | virtualenv | conda | …): conda
• Jupyter server running: Local

Expected behaviour

When editing a notebook, lines ending in “\n” shouldn’t be modified to “\r\n”

Actual behaviour

It appears as soon as I modify the content of a cell, the editor is replacing all “\n” by “\r\n”. I don’t understand why, and it’s causing downstream tools (e.g. nbdev/nbparse) to no longer be able to parse the .ipynb properly.

Steps to reproduce:

This seems to happen for any .ipynb file on my PC. I did a git clone of nbdev (https://github.com/fastai/nbdev/blob/master/nbs/00_export.ipynb) and ran the notebook, but chances are you only need to open a file:

1. download https://github.com/fastai/nbdev/blob/master/nbs/00_export.ipynb
2. open the file in vscode
3. modify a cell
4. do a diff on the cell.
5. notice that the newlines are messed up.

Logs

Output for Jupyter in the Output panel (View→Output, change the drop-down the upper-right of the Output panel to Jupyter)

User belongs to experiment group 'pythonJoinMailingListVar1'
User belongs to experiment group 'jupyterTest'
User belongs to experiment group 'NativeNotebookEditor'
> D:\Users\claforte\Anaconda3\envs\fastai\python.exe c:\Users\claforte\.vscode-insiders\extensions\ms-toolsai.jupyter-2020.12.414227025\pythonFiles\pyvsc-run-isolated.py -c "import jupyter"
> D:\Users\claforte\Anaconda3\envs\fastai\python.exe c:\Users\claforte\.vscode-insiders\extensions\ms-toolsai.jupyter-2020.12.414227025\pythonFiles\pyvsc-run-isolated.py -c "import notebook"
> D:\Users\claforte\Anaconda3\envs\fastai\python.exe c:\Users\claforte\.vscode-insiders\extensions\ms-toolsai.jupyter-2020.12.414227025\pythonFiles\pyvsc-run-isolated.py jupyter kernelspec --version
> D:\Users\claforte\Anaconda3\envs\fastai\python.exe c:\Users\claforte\.vscode-insiders\extensions\ms-toolsai.jupyter-2020.12.414227025\pythonFiles\pyvsc-run-isolated.py vscode_datascience_helpers.daemon --daemon-module=vscode_datascience_helpers.jupyter_daemon -v
> D:\Users\claforte\Anaconda3\envs\fastai\python.exe c:\Users\claforte\.vscode-insiders\extensions\ms-toolsai.jupyter-2020.12.414227025\pythonFiles\pyvsc-run-isolated.py vscode_datascience_helpers.daemon --daemon-module=vscode_datascience_helpers.jupyter_daemon -v
> D:\Users\claforte\Anaconda3\envs\fastai\python.exe c:\Users\claforte\.vscode-insiders\extensions\ms-toolsai.jupyter-2020.12.414227025\pythonFiles\pyvsc-run-isolated.py vscode_datascience_helpers.daemon --daemon-module=vscode_datascience_helpers.jupyter_daemon -v
> D:\Users\claforte\Anaconda3\envs\tensorflow\python.exe c:\Users\claforte\.vscode-insiders\extensions\ms-toolsai.jupyter-2020.12.414227025\pythonFiles\pyvsc-run-isolated.py -c "import ipykernel"
> D:\Users\claforte\Anaconda3\envs\fastai\python.exe c:\Users\claforte\.vscode-insiders\extensions\ms-toolsai.jupyter-2020.12.414227025\pythonFiles\pyvsc-run-isolated.py -c "import ipykernel"
> D:\Users\claforte\Anaconda3\envs\fastai\python.exe c:\Users\claforte\.vscode-insiders\extensions\ms-toolsai.jupyter-2020.12.414227025\pythonFiles\pyvsc-run-isolated.py vscode_datascience_helpers.daemon --daemon-module=vscode_datascience_helpers.kernel_launcher_daemon -v
Started kernel Python 3
> D:\Users\claforte\Anaconda3\envs\fastai\python.exe c:\Users\claforte\.vscode-insiders\extensions\ms-toolsai.jupyter-2020.12.414227025\pythonFiles\pyvsc-run-isolated.py vscode_datascience_helpers.daemon --daemon-module=vscode_datascience_helpers.kernel_launcher_daemon -v
> D:\Users\claforte\Anaconda3\envs\fastai\python.exe c:\Users\claforte\.vscode-insiders\extensions\ms-toolsai.jupyter-2020.12.414227025\pythonFiles\pyvsc-run-isolated.py vscode_datascience_helpers.daemon --daemon-module=vscode_datascience_helpers.kernel_launcher_daemon -v
> D:\Users\claforte\Anaconda3\envs\fastai\python.exe c:\Users\claforte\.vscode-insiders\extensions\ms-toolsai.jupyter-2020.12.414227025\pythonFiles\pyvsc-run-isolated.py vscode_datascience_helpers.daemon --daemon-module=vscode_datascience_helpers.kernel_launcher_daemon -v

XXX

[msveshnikov]

This is honestly very annoying behavior (I mean conversion of LF to CRLF). After such a notebook uploaded to Jupyter Lab server, I start to have incorrect character typed. This is another bug of Jupyter Lab, which unfortunately destroy your DEV experience. See here: https://github.com/jupyterlab/jupyterlab/issues/2951 (bug reproduced in latest Jupyter Lab) So basically after editing of a notebook in VSCode you have destroyed notebook in any external server!

[joyceerhl]

Users can configure the files.eol setting as a temporary workaround, and we can consider fixing this in the builtin ipynb extension. Note also that Colab always uses LF (they just fixed this behavior) https://github.com/jupyterlab/jupyterlab/issues/9465#issuecomment-802215114 /cc @roblourens @DonJayamanne