### Checklist - [X] I am confident this is a bug in CPython, not a bug in a third-party project - [X] I have searched the [CPython issue tracker](https://github.com/python/cpython/issues?q=is%3Aissue+sort%3Acreated-desc), and am confident this bug has not been reported before ### CPython versions tested on: 3.12, CPython main branch ### Operating systems tested on: macOS ### Output from running 'python -VV' on the command line: Python 3.11.3 (main, May 8 2023, 13:16:43) [Clang 14.0.3 (clang-1403.0.22.14.1)] ### A clear and concise description of the bug: The tokenizer has an infinite recursion when emitting an invalid escape sequence `SyntaxWarning`. This was probably introduced in #106993. Fix will be up shortly. <!-- gh-linked-prs --> ### Linked PRs * gh-107968 * gh-107970 <!-- /gh-linked-prs -->