Pyarrow 20 compatibility

[fjetter]

collection failure
distributed/protocol/tests/test_highlevelgraph.py:7: in <module>
    dd = pytest.importorskip("dask.dataframe")
../../../miniconda3/envs/dask-distributed/lib/python3.12/site-packages/dask/dataframe/__init__.py:25: in <module>
    from dask.dataframe.dask_expr import (
../../../miniconda3/envs/dask-distributed/lib/python3.12/site-packages/dask/dataframe/dask_expr/__init__.py:3: in <module>
    from dask.dataframe.dask_expr import datasets
../../../miniconda3/envs/dask-distributed/lib/python3.12/site-packages/dask/dataframe/dask_expr/datasets.py:10: in <module>
    from dask.dataframe.dask_expr._collection import new_collection
../../../miniconda3/envs/dask-distributed/lib/python3.12/site-packages/dask/dataframe/dask_expr/_collection.py:15: in <module>
    from fsspec.utils import stringify_path
../../../miniconda3/envs/dask-distributed/lib/python3.12/site-packages/fsspec/__init__.py:13: in <module>
    class AbstractFileSystem(AbstractFileSystem, pa.filesystem.DaskFileSystem):
E   AttributeError: module 'pyarrow' has no attribute 'filesystem'

This appears to originate from fsspec cc @martindurant

[fjetter]

Well, this is a bit odd. The code of fsspec is not what the traceback suggests. The mamba list of the CI jobs claim this was fsspec 2025.3.2

However, the code that is shown in the tracback dates back to 0.2.0 https://github.com/fsspec/filesystem_spec/blob/0.2.0/fsspec/__init__.py

This also explains the other errors about stringify_path

[jrbourbeau]

Closed via #9069