conda install hangs indefinitely and pip install has unresolved conflicting dependencies

[kovar-ursa]

I cannot install traffic using the documented conda or pip mechanisms.

Conda:

I installed a fresh copy of miniconda.
I then did:

conda config --set channel_priority strict
conda config --add channels conda-forge
conda create -n traffic -c conda-forge python=3.9 traffic

This hung indefinitely on solving environment.

I then created a new environment with just python=3.9 and did conda install traffic in it, with the same results.

Pip:

Again using a fresh python 3.9 environment I did:

pip install --upgrade traffic

This produced:

    traffic 2.6.6 depends on Cartopy<0.20.0 and >=0.19.0
    traffic 2.6.5 depends on Cartopy<0.20.0 and >=0.19.0
    traffic 2.6.4 depends on Cartopy<0.20.0 and >=0.19.0
    traffic 2.6.3 depends on Cartopy<0.20.0 and >=0.19.0
    traffic 2.6.2 depends on Cartopy<0.20.0 and >=0.19.0
    traffic 2.6.1 depends on Cartopy
    traffic 2.6 depends on Cartopy
    traffic 2.5 depends on Cartopy
    traffic 2.4 depends on Cartopy
    traffic 2.3 depends on Cartopy
    traffic 2.2 depends on Cartopy
    traffic 2.1 depends on Cartopy
    traffic 2.0 depends on Cartopy
    traffic 1.2 depends on Cartopy
    traffic 1.1.1 depends on Cartopy
    traffic 1.1 depends on Cartopy
    traffic 1.0 depends on geodesy
    traffic 0.1 depends on geodesy

To fix this you could try to:
1. loosen the range of package versions you've specified
2. remove package versions to allow pip attempt to solve the dependency conflict

ERROR: ResolutionImpossible: for help visit https://pip.pypa.io/en/latest/user_guide/#fixing-conflicting-dependencies

[kovar-ursa]

conda finally solved the environment, hours after it started. It has a -lot- of dependencies. Closing the ticket.

[xoolive]

When things go wrong with conda, consider mamba. Its resolution engine is very much optimised.

[xoolive]

Also starting with a new environment helps 🤷‍♂️