`jupyter notebook` gives error: `"Could not open static file ''"` on macOS - jupyter-notebook

Question

I haven't changed my system configuration, But I'm spotting this error for the first time today.
I've reported it here: https://github.com/jupyter/notebook/issues/4871
> jupyter notebook
[I 10:44:20.102 NotebookApp] JupyterLab extension loaded from /usr/local/anaconda3/lib/python3.7/site-packages/jupyterlab
[I 10:44:20.102 NotebookApp] JupyterLab application directory is /usr/local/anaconda3/share/jupyter/lab
[I 10:44:20.104 NotebookApp] Serving notebooks from local directory: /Users/pi
[I 10:44:20.104 NotebookApp] The Jupyter Notebook is running at:
[I 10:44:20.104 NotebookApp] http://localhost:8888/?token=586797fb9049c0faea24f2583c4de32c08d45c89051fb07d
[I 10:44:20.104 NotebookApp] or http://127.0.0.1:8888/?token=586797fb9049c0faea24f2583c4de32c08d45c89051fb07d
[I 10:44:20.104 NotebookApp] Use Control-C to stop this server and shut down all kernels (twice to skip confirmation).
[C 10:44:20.110 NotebookApp]
To access the notebook, open this file in a browser:
file:///Users/pi/Library/Jupyter/runtime/nbserver-65385-open.html
Or copy and paste one of these URLs:
http://localhost:8888/?token=586797fb9049c0faea24f2583c4de32c08d45c89051fb07d
or http://127.0.0.1:8888/?token=586797fb9049c0faea24f2583c4de32c08d45c89051fb07d
[E 10:44:21.457 NotebookApp] Could not open static file ''
[W 10:44:21.512 NotebookApp] 404 GET /static/components/react/react-dom.production.min.js (::1) 9.02ms referer=http://localhost:8888/tree?token=BLA
[W 10:44:21.548 NotebookApp] 404 GET /static/components/react/react-dom.production.min.js (::1) 0.99ms referer=http://localhost:8888/tree?token=BLA
Set
Looks like this issue was fixed in Jupyter 6.0.1
So the question becomes: can I force-install jupyter 6.0.1?
As the initial question has now provoked a second question, I now ask this new question here: How to force `conda` to install the latest version of `jupyter`?
Alternatively I can manually provide the missing file, but I'm not sure where. I've asked here: Where does Jupyter install site-packages on macOS?
Research:
https://github.com/jupyter/notebook/pull/4772 "add missing react-dom js to package data #4772" on 6 Aug 2019
minrk added this to the 6.0.1 milestone on 18 Jul
Ok, so can I get Jupyter Notebook 6.0.1?
brew cask install anaconda downloads ~/Library/Caches/Homebrew/downloads/{LONG HEX}--Anaconda3-2019.07-MacOSX-x86_64 which is July, and conda --version reports conda 4.7.10. But this is for Anaconda which is the Package Manager.
> conda list | grep jupy
jupyter 1.0.0 py37_7
jupyter_client 5.3.1 py_0
jupyter_console 6.0.0 py37_0
jupyter_core 4.5.0 py_0
jupyterlab 1.0.2 py37hf63ae98_0
jupyterlab_server 1.0.0 py_0
So that's a bit confusing. No jupyter notebook here.
> which jupyter
/usr/local/anaconda3/bin/jupyter
> jupyter --version
jupyter core : 4.5.0
jupyter-notebook : 6.0.0
qtconsole : 4.5.1
ipython : 7.6.1
ipykernel : 5.1.1
jupyter client : 5.3.1
jupyter lab : 1.0.2
nbconvert : 5.5.0
ipywidgets : 7.5.0
nbformat : 4.4.0
traitlets : 4.3.2
Ok, so it appears jupyter-notebook is in jupyter which is maintained by Anaconda.
Can we update this?
https://jupyter.readthedocs.io/en/latest/projects/upgrade-notebook.html
> conda update jupyter
:
Alas jupyter --version is still 6.0.0

Answer 1

I fixed this by updating both jupyter on pip and pip3 (just to be safe) and this fixed the problem
using both
pip install --upgrade jupyter
and
pip3 install --upgrade jupyter --no-cache-dir
I believe you can do this in the terminal as well as in conda's terminal (since conda envs also have pip)

Answer 2

As per Where does Jupyter install site-packages on macOS?, I locate where on my system jupyter is searching for this missing file:
> find / -path '*/static/components' 2>/dev/null
/usr/local/anaconda3/pkgs/notebook-6.0.0-py37_0/lib/python3.7/site-packages/notebook/static/components
/usr/local/anaconda3/lib/python3.7/site-packages/notebook/static/components
And as per https://github.com/jupyter/notebook/pull/4772#issuecomment-515794823, if I download that file and deposit it in the second location, i.e. creating:
/usr/local/anaconda3/lib/python3.7/site-packages/notebook/static/components/react/react-dom.production.min.js
... now jupyter notebook launches without errors.
(NOTE: Being cautious I have also copied it into the first location. But that doesn't seem to have any effect.)