[FR] External Data Support

What’s the problem this feature will solve?

Project Jupyter uses data_files for discovery of runtime extensions. This feature was deprecated without a viable alternative.

Describe the solution you’d like

The flit project recently added support for external_data, which is a simplified and constrained version of data_files. We could support an equivalent feature in setuptools, with caveats about when it is appropriate to use it.

Alternative Solutions

Project Jupyter and other current consumers of data_files could instead switch to using a flit backend, which we have been actively exploring.

Additional context

Project Jupyter uses data_files to allow libraries to provide shared setting and static assets files that are consumed by Jupyter at runtime. We have explored using entry_points for this purpose, but it did not scale well.

Code of Conduct

• I agree to follow the PSF Code of Conduct

[blink1073]

If there’s buy-in I can take a crack at implementation.

[blink1073]

Hi @ofek, thanks for pointing that out! The consensus at the summit was that I should draft a PEP to standardize the handling of the data and headers directories for build backends. I will use flit and hatch as existing implementation examples.

As for Jupyter, we could have used flit already (in fact I had a WIP), but many of the consumers of jupyter-packaging are using setuptools-specific mechanisms and extensions.