Cookies set in middleware are unavailable on initial render

[dnewbound0]

Currently, the x-middleware-set-cookie header is being removed from the middleware response:

opennextjs-aws/packages/open-next/src/core/routing/middleware.ts

Lines 116 to 123 in c212ed0

	const filteredHeaders = [
	"x-middleware-override-headers",
	"x-middleware-set-cookie",
	"x-middleware-next",
	"x-middleware-rewrite",
	// We need to drop `content-encoding` because it will be decoded
	"content-encoding",
	];

When reading cookies() the value of this header is merged into the existing cookies object: https://github.com/vercel/next.js/blob/f62a135d9bde6e92b9f8f50d236b5de02de74400/packages/next/src/server/async-storage/request-store.ts#L83
https://github.com/vercel/next.js/blob/f62a135d9bde6e92b9f8f50d236b5de02de74400/packages/next/src/server/async-storage/request-store.ts#L211
So removing this header breaks reading a cookie that was set by the middleware for that request, as shown here

middleware.ts:

export function middleware(request: NextRequest) {
  const response = NextResponse.next()
  response.cookies.set("foo", "bar")

  return response
}

app/page.tsx:

import { cookies } from "next/headers";

export default async function Page() {
  // On initial render, this will be undefined!
  const foo = cookies().get("foo")?.value

  return <div>{foo}</div>
}