Problem with dependency resolution w/ myst-nb and jupytext

[rossbar]

Describe the bug

If anything, this is likely a bug with the pip dependency resolver, but I wanted to raise here for visibility. Listing both myst-nb and jupytext in a requirements.txt file will cause pip to fail.

To Reproduce

Add both myst-nb and jupytext to a requirements file and try to install it w/ pip -r in a fresh virtual environment.

1. `echo -e "myst-nb\njupytext" > borked_requirements.txt
2. In a clean venv: pip install -r borked_requirements.txt

Note that you get the same behavior if you try to install jupytext and myst-nb in one step: pip install jupytext myst-nb.

The workaround is to install them in separate steps. This will complete, and pip raises a more informative error:

pip install myst-nb
pip install jupytext
...
ERROR: pip's dependency resolver does not currently take into account all the packages that are installed. This behaviour is the source of the following dependency conflicts.
myst-parser 0.12.10 requires markdown-it-py~=0.5.4, but you have markdown-it-py 0.6.1 which is incompatible.
Successfully installed jupytext-1.9.1 markdown-it-py-0.6.1 mdit-py-plugins-0.2.4 toml-0.10.2

Expected behavior

Just reporting for visibility - maybe the myst-nb or jupytext version requirements could be updated to prevent this collision.

Environment

• Python Version [e.g. 3.7.1]: 3.9.1
• pip versions tried: 20.3.1 and 20.3.3
• Package versions:
  versions are unpinned in the requirements file, so pip tries to grab myst-nb v0.10.1 and jupytext v1.9.1
• Operating System: linux

[choldgraf]

thanks for bringing this up! I believe that @chrisjsewell is nearing another release of myst-nb that should resolve this, just FYI :-)

[chrisjsewell]

done in https://github.com/executablebooks/MyST-NB/releases/tag/v0.11.0