pyschism dependency conflict with recent dask versions

[mansurjisan]

The conda version of pyschism is failing to import due to a dependency conflict. Specifically, the cf-python package (version 3.16.1) attempts to import collections_to_dsk from dask.base, but this function has been removed or renamed in recent dask versions (2025.4.1). I am currently investigating the issue.

Error Message

ImportError: cannot import name 'collections_to_dsk' from 'dask.base' (/home/mjisan/miniconda3/envs/pyschism_test/lib/python3.10/site-packages/dask/base.py)

Reproduction Steps

1. Create a conda environment with pyschism
2. Try to import the package
3. Observe the import error related to dask dependency

Environment Information

• pyschism version: 0.1.15
• Python version: 3.10.13
• dask-core version: 2025.4.1
• cf-python version: 3.16.1
• Operating system: Linux

Temporary Workaround

Downgrading dask-core to version 2023.3.0 resolves the issue:

conda install -c conda-forge dask-core=2023.3.0

Impact on UFS-Coastal Workflow

This issue might affect any UFS-Coastal workflows that rely on pyschism. Users upgrading their environments might encounter failing imports if their dask version is automatically updated to newer incompatible versions.

Additional Notes

The issue appears to be a compatibility problem between cf-python and recent dask versions. In the long term, cf-python should be updated to work with the newer dask API.