Resolve content links from their source file after rendering.

[koculu]

Summary

Relative links in content now resolve from the file that wrote them, and the build fails when one points to a page that doesn't exist.

Previously only links ending in .md, .mdx or .rmdx were rewritten. Anything else, like [themes](./themes), was left for the browser to resolve against the page URL. Page URLs end in a slash, so on a page like guides/semantic-tones.mdx (/guides/semantic-tones/) that link went to /guides/semantic-tones/themes. It only worked by coincidence on folder index pages.

The rule

• Relative links (./themes, ../, ./components/buttons) resolve from the source file, with or without an extension. They must match a page, or the build fails with the file and the link in the message.
• Root-absolute links (/blog/) are left as written and aren't checked, so they can point to pages built separately.
• External, hash, query and asset links are unchanged.

An extensionless path finds the file first (a/c.mdx), then the folder page (a/c/index.mdx or a/c/c.mdx). A trailing slash checks the folder first. A translated page that links to an untranslated one gets the default-locale page.

How it works

• Links are resolved on the rendered DOM. renderApp gains an onRendered(document) hook. A single pass (build/page-urls.ts) resolves every href after Regor renders. That covers Markdown links, raw HTML, Regor components and bound values like :href="nextPage". Code samples, comments and script text are never touched, because they aren't elements.
• Header and footer partials are wrapped in a marker that names their file, so their links resolve from the partial. The marker is removed before output.
• The base path is added in the same pass. This replaces the regex in public-hrefs.ts; mdx/linkRewrite.ts is removed as well.
• The route index (ContentRouteIndex) checks links against discovered pages in memory, without touching the disk.
• Incremental builds keep the index current. Adding or removing a page marks every page dirty, now also when navigation is off.

Behavior changes

• A broken relative link fails build. In serve, it shows on that page's error page.
• BtnLink and FormAssistLink no longer turn ./x into /x; relative values are kept and resolved by the page pass.
• Relative links from templates or head config follow the same rule, resolving from the page's file.
• Content that a component moves out of the header (e.g. teleport="head") resolves from the page's file.

Docs

New Links guide in guides/, added to the nav and the guides index. The semantic tones guide now uses ./themes.

Testing

• Unit tests for the resolver, including every source page of a folder/leaf layout plus encoding, case, Windows paths and i18n.
• Unit tests for the DOM pass, including markers, templates, escaping and base path.
• Page-level tests: Markdown, HTML, static and computed BtnLink, header links, and broken links.
• Incremental tests for adding, deleting and editing pages, with navigation on and off.
• The purestack.studio site builds with every link resolved, at the same build time as before.