From 8b4bb031ba2d83bb48cf665b556f1b1c8a7d34b9 Mon Sep 17 00:00:00 2001
From: Justin Ridgewell <justin@ridgewell.name>
Date: Wed, 30 Aug 2023 17:14:46 -0400
Subject: [PATCH] Fixes for Turbopack HMR (#54790)

### What?

There were a few issues with the initial implementation of next-api HMR:
1. We incorrectly errored out when we received a Next.js WebSocket message
2. We didn't handle Next's `span-end` message, leading to another error
3. We listened to the `htmlEndpoint` change events instead of the `dataEndpoint`/`rscEndpoint`, leading to us detecting client-side changes and causing full page reloads

### Why?

HMR is the life-blood of development

### How?

Small fixes to our Turbopack reimplementation of the server-side HRM handlers

Closes WEB-1475
---
 packages/next/src/server/lib/router-utils/setup-dev.ts | 10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)

diff --git a/packages/next/src/server/lib/router-utils/setup-dev.ts b/packages/next/src/server/lib/router-utils/setup-dev.ts
index 396508617d..1552000e57 100644
--- a/packages/next/src/server/lib/router-utils/setup-dev.ts
+++ b/packages/next/src/server/lib/router-utils/setup-dev.ts
@@ -754,6 +754,7 @@ async function startWatcher(opts: SetupOpts) {
               case 'server-component-reload-page': // { clientId }
               case 'client-reload-page': // { clientId }
               case 'client-full-reload': // { stackTrace, hadRuntimeError }
+              case 'span-end': // { startTime, endTime, spanName, attributes }
                 // TODO
                 break
 
@@ -775,7 +776,10 @@ async function startWatcher(opts: SetupOpts) {
                 break
 
               default:
-                throw new Error(`unrecognized Turbopack HMR message "${data}"`)
+                // Might have been a Next.js message...
+                if (!parsedData.event) {
+                  throw new Error(`unrecognized Turbopack message "${data}"`)
+                }
             }
           })
 
@@ -886,7 +890,7 @@ async function startWatcher(opts: SetupOpts) {
               page,
               await route.htmlEndpoint.writeToDisk()
             )
-            changeSubscription(page, route.htmlEndpoint, (pageName, change) => {
+            changeSubscription(page, route.dataEndpoint, (pageName, change) => {
               switch (change) {
                 case ServerClientChangeType.Server:
                 case ServerClientChangeType.Both:
@@ -939,7 +943,7 @@ async function startWatcher(opts: SetupOpts) {
           }
           case 'app-page': {
             await processResult(page, await route.htmlEndpoint.writeToDisk())
-            changeSubscription(page, route.htmlEndpoint, (_page, change) => {
+            changeSubscription(page, route.rscEndpoint, (_page, change) => {
               switch (change) {
                 case ServerClientChangeType.Server:
                 case ServerClientChangeType.Both: