404 on deep link don't have correct css url

[AugustinMauroy]

on https://beta.docs.nodejs.org/foo/bar the we go 404 on ressources

[Error] Failed to load resource: the server responded with a status of 404 () (styles.css, line 0)

the actual link is https://beta.docs.nodejs.org/foo/styles.css

[franko-c]

looks like template.html:10 — href="${root}styles.css" gets root from processing.mjs:134, which calls relativeOrAbsolute('/', data.path). for the 404 page, data.path is /404 (set in 404.mjs), so relative('/', '/404') returns '.' and root becomes './'. the web server then serves this same HTML at any failed URL — at /foo/bar, ./styles.css resolves to /foo/styles.css instead of /styles.css. same pattern on line 29 for the script entrypoint.

hardcoding root to / for synthetic pages in 404.mjs would fix deep links without breaking the relative-path logic for normal pages. not sure if useAbsoluteURLs is intentionally off for the beta deployment or if switching it on globally would be the broader fix.

[avivkeller]

We should hardcode {baseURL}/ for synthetic pages, since we don't know if / is the root of the web server or the root of our application

[franko-c]

from what I can see on current main, processing.mjs:134 still sets root via relativeOrAbsolute('/', data.path) for all pages including synthetics. your {baseURL}/ hardcode for synthetics makes sense — happy to open a PR with that if useful.