Mamba solver sometimes stuck in a loop (when combining defaults + conda-forge)

[wolfv]

I believe due to the python_abi dependency in conda-forge's python packages libsolv sometimes end up in some sort of loop. For example this environment:

name: geostacks
channels:
  - conda-forge
  - defaults
dependencies:
  # - python
  - boto3
  - cycler
  - cython
  - dask
  - datashader
  - flake8
  - gdal
  - geos
  - h5py
  - intake
  - ipyleaflet
  - ipympl
  - ipywidgets
  - joblib
  - jupyter
  - jupyterlab
  - matplotlib
  - netcdf4
  - numba
  - numpy
  - pandas
  - pillow
  - pip
  - pyproj
  - rasterio
  - scikit-learn
  - scipy
  - seaborn
  - shapely
  - six
  - xarray

Will loop forever.

Uncommenting python at the top will make it resolve to a good environment, though.

Maybe with "more strict" strict channel priority we can alleviate this issue.

[wolfv]

with the new default behavior, I think this is fixed.