BUG: UndefinedVariableError in DataFrame.query with classname
- [x] closes #48694
- [x] [Tests added and passed](https://pandas.pydata.org/pandas-docs/dev/development/contributing_codebase.html#writing-tests) if fixing a bug or adding a new feature
- [x] All [code checks passed](https://pandas.pydata.org/pandas-docs/dev/development/contributing_codebase.html#pre-commit).
- [ ] Added [type annotations](https://pandas.pydata.org/pandas-docs/dev/development/contributing_codebase.html#type-hints) to new arguments/methods/functions.
- [x] Added an entry in the latest `doc/source/whatsnew/v1.5.2.rst` file if fixing a bug or adding a new feature.

xref #47859
The doc build error may possibly be related? https://github.com/pandas-dev/pandas/actions/runs/3303682683/jobs/5451910616 Thanks for the feedback @mroeschke.
I see a lot of exceptions in `user_guide/enhancingperf.rst`, but I was able to build it locally without any error. Any advice how I can figure this out? Did you build the docs locally with the `--warnings-are-errors` flag? I used both `--warnings-are-errors --single user_guide/enhancingperf.rst`, didn't throw any error. From the logs it appears that the errors are not just in `--single user_guide/enhancingperf.rst` so maybe try building the entire dogs with the `--warnings-are-errors` flag I was able to replicate the error in the docs with that. But not able to identify why it's throwing `ValueError` in the docs, but not in the terminal for the exact same thing. This pull request is stale because it has been open for thirty days with no activity. Please [update](https://pandas.pydata.org/pandas-docs/stable/development/contributing.html#updating-your-pull-request) and respond to this comment if you're still interested in working on this. Should also fix ~#49248~ #50442  Thanks for the pull request, but it appears to have gone stale. If interested in continuing, please merge in the main branch, address any review comments and/or failing tests, and we can reopen.