Caching data in workflows is not working

[felixhekhorn]

Warning: Path Validation Error: Path(s) specified in the action for caching do(es) not exist, hence no cache is being saved.

from https://github.com/NNPDF/eko/actions/runs/13971535800/job/39114365372#step:25:2

this is because this

eko/.github/workflows/python-poetry-tests-with-data.yml

Line 82 in c69a7b9

path: test-data

is just wrong

This holds in all places where the cache is used:

• Python unit tests
• PyPI
• Rust unit tests

The solution will imply a series of steps, which include at least:

• make the path a parameter in the Python workflow files - for Rust it is hard coded
• do something against linking the file for Rust from Python. Currently the link is created when downloading, this will break when we only download once. Solution might be to permanently link the directory

[felixhekhorn]

When resolving the data cache we can also improve the independent poetry cache by adjusting the Python action- see https://github.com/actions/setup-python?tab=readme-ov-file#caching-packages-dependencies . Thanks to @alecandido for pointing out.

[felixhekhorn]

Further improvement suggested by @Radonirinaunimi in PineAPPL

But I just realized that one can extract the caching logic into a separate reusable workflow and simply call:

jobs:
  download-test-data:
    uses: ./.github/workflows/cache-test-data.yml

[felixhekhorn]

@evagroenendijk this is the other issue I was thinking of