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
```text
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.
2. Upgrade ray to a pandas-2-compatible release:
   ```
   pip install -U ray
   ```
   Expected: installs a newer ray.
3. Verify:
   ```
   python -c "import ray; print(ray.__version__)"
   ```
   Expected: imports cleanly.
4. 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.