Turbopack: Implement HMR in next-api (#54772)
by @jridgewell:
### What?
This integrates Turbopack's HRM protocol within the existing HMR
WebSocket, and implements the server-side of the Next's and Turbopack's
protocols for use in next-api.
### Why?
HMR makes the development experience.
### How?
The (new) Turbopack HMR protocol allows reusing the existing
`sendMessage` and `addMessageListener` API's already used by our HMR
singleton in Pages. (App apparently doesn't have a per-chunk HMR, only
per-page, so it's HMR signals are describe below.)
For the next-api server-side, I implemented the following events:
- `reloadPage`, for Pages when `_document` changes
- `middlewareChanges` when middleware is added/deleted, or modified
- `serverOnlyChanges` for Pages when a loaded page's server graph
changes
- `serverComponentChanges` for App when a loaded app page's server graph
changes
We reuse the already implemented `addedPage`, `removedPage`, and
`devPagesManifestUpdate` (done via webpack, so we should eventually port
that over to the Turbopack listeners).
I don't know exactly where `built`, `building`, and `sync` should be
integrated, so they're just not sent currently. Additionally, the
client-sent events aren't implemented in the new HMR server.
Depends on https://github.com/vercel/turbo/pull/5814
Closes WEB-1453
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Co-authored-by: Justin Ridgewell <justin@ridgewell.name>
