From https://github.com/vercel/next.js/pull/20628, when the page is rendered server-side, `Router`'s `isReady` field needs to be initially set to `true`. However, when `_app` has custom `getInitialProps`, it seems that it is not the case, even though the page is rendered on the server.
This leads to a bug that `Router.isReady` is never set to `true`.
This pull request fixes the problem by fixing the initial calculation logic of `isReady` of `Router`.
## Bug
- [ ] Related issues linked using `fixes #number`
- [x] Integration tests added
- [ ] Errors have helpful link attached, see `contributing.md`
## Feature
- [ ] Implements an existing feature request or RFC. Make sure the feature request has been accepted for implementation before opening a PR.
- [ ] Related issues linked using `fixes #number`
- [ ] Integration tests added
- [ ] Documentation added
- [ ] Telemetry added. In case of a feature if it's used or not.
- [ ] Errors have helpful link attached, see `contributing.md`
## Documentation / Examples
- [x] Make sure the linting passes
Currently there is a lot of mutation in the Next.js Server and the checks for Locale are directly coded in the general request handler. Ideally, we should have a function where we just pass the request input (url + headers + config) and generate a bunch of metadata that analyzes it generating all metadata we might require for both the URL and i18n + basePath information.
This PR brings:
- A new parsing function `parseUrl` that joins parsing an absolute/relative URL into a data structure compatible with the Node parsing output but missing redundant properties.
- A wrapper `parseNextURL` that extends `parseUrl` analyzing `i18n` and `basePath` based on the provided configuration, url and headers. This function is pure and stateless so it can be used outside of the Next.js context.
- Types improvements and reuse.
- Refactors `next-server.ts` request handling using the above mentioned functions so that the code there just apply effects to the `req` object and the `parsedUrl.query` leaving the code much more straightforward.
- Refactors `getRouteRegex` decomposing in two different functions where `getParametrizedRoute` can be used to retrieve the serializable data that is used to generate the Regex.
How a page is rendered depends on whether or not we're streaming. For example, if we're just rendering to a `string` or we're generating a response for a crawler or other robot, we don't want React 18 to dynamically flush `<script>` tags to update Suspense boundaries as they resolve. Instead, we just want to wait for the full HTML to resolve and return a result similar to `renderToString`.
This is what `RequestContext` and the new/refactored `pipe` and `getStaticHTML` methods allow. They add a `requireStaticHTML` option that gets passed down. A follow-up PR will make sure this is `true` when serving a robot, and also ensure React is invoked appropriately.
