Regression Node 24.0.0+: parsing JSONL with U+2028 (line separator)/ U+2029 (paragraph separator)

Version

node v24.0.0+

What steps will reproduce the bug?

• Open a Node.js shell session (version 24.x or later).
• Run JSON.parse('{"text":"Hello
World"}') (The character between “Hello” and “World” is U+2028 (line separator). You can also use U+2029 (paragraph separator) instead.)

which will return with a Uncaught SyntaxError: Unexpected token ...

How often does it reproduce? Is there a required condition?

Always

What is the expected behavior? Why is that the expected behavior?

Summary

Note: V8's "Subsume JSON" documentation explicitly discusses making these code points processable in JavaScript string literals (https://v8.dev/features/subsume-json). Given that, this change is surprising and breaks existing production pipelines.

What do you see instead?

After upgrading to Node v24.x, JSON.parse() now throws a SyntaxError when parsing JSON text that contains literal U+2028 (line separator) or U+2029 (paragraph separator) inside a string value. The same input parsed successfully on Node v23.x. This looks like a regression or at least an undocumented behaviour change in Node/V8.

Comienza reproduciendo el ejemplo de JSON.parse en Node v24 y compáralo con Node v23, centrándote en la ruta de análisis de JSON y en el tratamiento de los literales U+2028 y U+2029 dentro de las cadenas. El issue no menciona archivos de código fuente ni tests, así que rastrea el punto de entrada relevante del runtime o de V8 y añade cobertura que demuestre que la entrada se analiza correctamente sin cambiar ningún otro comportamiento de JSON.