add floor on nbformat

[jameslamb]

Checklist

• Used a personal fork of the feedstock to propose changes
• Bumped the build number (if the version is unchanged)
• Reset the build number to 0 (if the version changed)
• Re-rendered with the latest conda-smithy (Use the phrase @conda-forge-admin, please rerender in a comment in this PR for automated rerendering)
• Ensured the license file is being packaged.

Proposed changes

• adds a floor of nbformat>=5.2.0

Impact

Without these changes, it's possible to get into a situation with incompatible jupyter_server and nbformat versions, which prevents creation of notebooks (at least in Jupyter Lab).

Reproducible example

output of 'conda info'

     active environment : None
       user config file : /Users/James.Lamb/.condarc
 populated config files : 
          conda version : 4.12.0
    conda-build version : not installed
         python version : 3.8.5.final.0
       virtual packages : __osx=10.16=0
                          __unix=0=0
                          __archspec=1=x86_64
       base environment : /Users/James.Lamb/miniconda3  (writable)
      conda av data dir : /Users/James.Lamb/miniconda3/etc/conda
  conda av metadata url : None
           channel URLs : https://repo.anaconda.com/pkgs/main/osx-64
                          https://repo.anaconda.com/pkgs/main/noarch
                          https://repo.anaconda.com/pkgs/r/osx-64
                          https://repo.anaconda.com/pkgs/r/noarch
          package cache : /Users/James.Lamb/miniconda3/pkgs
                          /Users/James.Lamb/.conda/pkgs
       envs directories : /Users/James.Lamb/miniconda3/envs
                          /Users/James.Lamb/.conda/envs
               platform : osx-64
             user-agent : conda/4.12.0 requests/2.27.1 CPython/3.8.5 Darwin/20.5.0 OSX/10.16
                UID:GID : 504:20
             netrc file : None
           offline mode : False

First, create an environment with older versions of jupyter_server and nbformat

conda config --add channels conda-forge
conda config --set channel_priority strict
conda create --name example --yes \
    python=3.9 \
    nbformat==5.1.3 \
    jupyterlab==3.3.2 \
    jupyter_server==1.13.5

Start up Jupyter Lab, then create and save notebook.

mkdir -p ${HOME}/sandbox/jserver-example
cd ${HOME}/sandbox/jserver-example
source activate example
jupyter lab

Exit Jupyter Lab, then update ONLY jupyter_server in that conda environment.

conda update --name example --yes \
    jupyter_server

Next, run JupyterLab and try to create and save a notebook.

jupyter lab

On loading, you'll see an error from the existing notebook.

File Load Error for test.ipynb
Unreadable Notebook: /Users/James.Lamb/sandbox/jserver-example/test.ipynb TypeError("init() got an unexpected keyword argument 'capture_validation_error'")

Try to create a new notebook in Jupyter Lab, you'll see a different error.

Error
Unexpected error while saving file: Untitled.ipynb [Errno 2] No such file or directory: '/Users/James.Lamb/sandbox/jserver-example/.~Untitled.ipynb' -> '/Users/James.Lamb/sandbox/jserver-example/Untitled.ipynb'

Exit Jupyter Lab, then update to a newer nbformat in the environment.

conda update --name example --yes \
    nbformat

The following packages will be UPDATED:
nbformat 5.1.3-pyhd8ed1ab_0 --> 5.2.0-pyhd8ed1ab_0

Run Jupyter Lab again...now notebooks load successfully and it's possible to create and save new ones.

Notes

Today, I updated a conda environment with jupyter_server in it, and found that I got the newest jupyter_server (v1.15.6) but that my nbformat version wasn't upgraded (I had 5.1.3, and the newest is 5.2.0).

As a result, I wasn't able to create notebooks in Jupyter Lab...saw the following error when creating a new notebook

File Load Error for explore.ipynb
Unreadable Notebook: /usr/local/src/notebooks/explore.ipynb TypeError("init() got an unexpected keyword argument 'capture_validation_error'")

After some investigation, I determined that this is because jupyter_server>=1.15.0 is incompatible with nbformat<5.2.0.

• Validate notebooks once per fetch or save jupyter-server/jupyter_server#724 passes argument capture_validation_error through to nbformat.write()
• prior to Add ability to capture validation errors jupyter/nbformat#249, nbformat.write() didn't accept that keyword argument, and instead passed it through **kwargs until it eventually got passed to json.dumps(), which generates the error above
• jupyter_server's package metadata for PyPI contains a floor of nbformat>=5.2.0: https://github.com/jupyter-server/jupyter_server/blob/619fd23aef7064f23e49e36e43b99beff97a7d5b/setup.cfg#L37

Notes for Reviewers

Thanks for your time and consideration!

[conda-forge-linter]

Hi! This is the friendly automated conda-forge-linting service.

I wanted to let you know that I linted all conda-recipes in your PR (recipe) and found some lint.

Here's what I've got...

For recipe:

• requirements: run: nbformat >= 5.2.0 should not contain a space between relational operator and the version, i.e. nbformat >=5.2.0

[conda-forge-linter]

Hi! This is the friendly automated conda-forge-linting service.

I just wanted to let you know that I linted all conda-recipes in your PR (recipe) and found it was in an excellent condition.

[jameslamb]

@conda-forge-admin, please rerender

[github-actions]

Hi! This is the friendly automated conda-forge-webservice.

I tried to rerender for you, but it looks like there was nothing to do.

This message was generated by GitHub actions workflow run https://github.com/conda-forge/jupyter_server-feedstock/actions/runs/2019986930.

[blink1073]

Thanks!