support `findSourceMapURL`

[hi-ogawa]

• [Flight] Add findSourceMapURL option to get a URL to load Server source maps from facebook/react#29708
  • this is only for error stack?
• [Flight] Source Map Server Actions to their Server Location facebook/react#30741
  • this is not implemented in fixtures? nor parcel?
  • next.js uses full arguments for createServerReference Add source map support for server components/actions in the browser vercel/next.js#71042

[hi-ogawa]

#779 added a basic support (for error stack and replay log), but the line seems a bit off. To be investigated.

The 2nd one is probably only for React dev tools and it requires updating createServerReference.

[hi-ogawa]

Okay, we probably need to do a series of "unwrap" PR just like Next.js

• Unwrap createServerReference, and pass additional parameters vercel/next.js#69190
• Unwrap createServerReference, and pass additional parameters vercel/next.js#69190

Then also need a mapping for proxy exports

• Create spans for createServerReference and registerServerReference vercel/next.js#70564

[hi-ogawa]

Let's just fix one by one

• action imported from client
  • createServerReference feat(rsc): support findSourceMapURL for createServerReference + feat(transforms)!: source map for proxy export transform #796
• action on server
  • registerServerReference
  • unwrapping is done by fix(transforms): disallow non async function for "use server" #797, but source map position of registerServerReference is not preserved yet.
  • fix(transforms): fix source map of registerServerReference calls #798