[Compiler Bug]: Compiler messes up with escape character

[jgangel]

What kind of issue is this?

• React Compiler core (the JS output is incorrect, or your app works incorrectly after optimization)
• babel-plugin-react-compiler (build issue installing or using the Babel plugin)
• eslint-plugin-react-compiler (build issue installing or using the eslint plugin)
• react-compiler-healthcheck (build issue installing or using the healthcheck script)

Link to repro

https://playground.react.dev/#N4Igzg9grgTgxgUxALhAgHgBwjALgAgBMEAzAQygBsCSoA7OXASwjvwFkBPAQU0wAoAlPmAAdNvjiswBVgGUoAIwC2TAgF58-BMPUA+EePzH8CAHSYYCAG4I6uACKkK1IQG4jJqXUiVzlCABzflEQBWVFNVwEQgBCUMEPCQBfJM8rXFg2EIljAB4SHGV8eSVVXHVgUpU1ZL1PE3w8pjpMKAJMMlxomDp1UNFRAHdQ-AB6etyTPMV23FZ8XE5MBH7wMrVQvQUa3Dyx2e7WScb9wphlE-xE8WTxEGSgA

Repro steps

Steps:

1. Open playground link attached
2. Expect the input element in JS tab to be <input pattern="\w" />, but it is <input pattern="\\w" /> instead, matching different regex than the one desired

How often does this bug happen?

Every time

What version of React are you using?

19.0.0

What version of React Compiler are you using?

19.0.0-beta-63e3235-20250105

[mofeiZ]

Thanks for the report! This is due to a bug in @babel/generator (also see #29069 and #29120) and should be fixed by #32131.