Notebook cell weirdness in 3.0rc11

[jasongrout]

Description

We're seeing very weird behavior for notebook cells in 3.0rc11. Note that the cell automatically getting longer right when it is created is something automatic, I'm not doing anything at first. Then typing new characters doesn't seem to work properly either.

Current hypotheses are that this is a problem with #9407, since the recent codemirror changes all seem to have been made in the 2.3.x branch.

Reproduce

1. Install 3.0rc11
2. create new notebook, try to add a cell and type text into the cell

Expected behavior

Things to work like in 3.0rc10 - cells appropriate size, typing a cell to show the text typed, etc.

Context

• Operating System and version: macos Catalina
• Browser and version: Firefox 83
• JupyterLab version: 3.0rc11

Troubleshoot Output

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Command Line Output

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[jasongrout]

I'm not seeing any 404s with files, so it doesn't seem that we just aren't including files in the package.

[jasongrout]

I'm seeing the same thing in current master: b2af792, and don't see it on a previous commit. I'm bisecting now...

[jasongrout]

Investigating, I see that our logic of substituting a js file in for a css file is causing problems. For example, in

jupyterlab/packages/codemirror/style/index.js

Line 11 in 510bfad

import 'codemirror/lib/codemirror';

we see that we are preferring to import the codemirror js instead of the codemirror css, but we really do want the css.

One way to deal with this is to make our substitution logic smarter. Only import the js file if it only has import statements, for example.

Or even better, let's just make it an explicit opt-in - a separate jupyterlab js style key that we prefer over the package.json style key.