[nbozidarevic]

Problem

The rsc:findSourceMapURL and vite-rsc-load-module-dev-proxy dev middlewares parse every incoming request URL with new URL(). Some request targets are valid HTTP but do not parse as URLs — for example // or //[ (a client probing the server root, or a mangled proxy path). The throw happens inside an async Connect middleware with no catch, so it surfaces as an unhandled rejection and kills the whole dev server process.

Repro: start any plugin-rsc dev server (e.g. the starter example with pnpm dev), then in another shell:

curl --path-as-is http://localhost:<port>//

On the unpatched build this throws TypeError [ERR_INVALID_URL]: Invalid URL from dist/plugin-*.js (the findSourceMapURL middleware).

Fix

Parse through a shared helper (parseRequestUrl in plugins/vite-utils) that returns undefined when the URL does not parse; both middlewares pass the request down the chain with next() instead of throwing. Unparseable requests fall through to Vite's own handling rather than crashing the server.

Testing

• New unit tests in plugins/vite-utils.test.ts cover normal URLs (/, the findSourceMapURL endpoint, undefined) and the // / //[ cases.
• Verified end to end against the starter example dev server: with the fix, curl --path-as-is // returns 200 and the server keeps serving subsequent requests, with no errors in the log.
• Full plugin-rsc unit suite (src/transforms + src/plugins, 527 tests) green. Package typecheck shows only the pre-existing example errors that also occur on clean main (missing built sibling types before pnpm build).