ImportError: cannot import name 'ExtensionArrayFormatter' from 'pandas.io.formats.format'

TL;DR: your ray version imports a private pandas helper that pandas 2.x removed. Upgrade ray to a release that supports pandas 2, or pin pandas below 2.0 as a workaround.

The error

ImportError: cannot import name 'ExtensionArrayFormatter' from 'pandas.io.formats.format'

Fix it

1. Check the versions in play:

   pip show ray pandas | grep -E "Name|Version"

Expected: shows ray and pandas versions; pandas is 2.x.

1. Upgrade ray to a pandas-2-compatible release:

   pip install -U ray

Expected: installs a newer ray.

1. Verify:

   python -c "import ray; print(ray.__version__)"

Expected: imports cleanly.

1. If you cannot upgrade ray, pin pandas instead:

   pip install "pandas<2.0"

Expected: the old import path exists again.

When this applies

Use this when import ray (or a ray submodule) raises this error with pandas 2.x installed.

When it does not apply

If your own code imports pandas.io.formats.format internals, stop using the private API instead. If ray is already current, reinstall it; the install may be corrupt.

Compatibility

ray releases before pandas 2 support landed; pandas 2.0+.

Root cause

ExtensionArrayFormatter was a private helper inside pandas.io.formats.format. pandas 2.0 refactored the formatting internals and removed it. ray imported the private name, so the removal broke ray at import time.

Edge cases

Pinning pandas below 2.0 can conflict with other packages that require pandas 2; upgrading ray is the cleaner path. In conda envs, update both from the same channel to avoid a mixed solve.