refactor(hmr): simplify fetchUpdate (#9881)

Author: sapphi-red

packages/vite/src/client/client.ts

@@ -400,46 +400,29 @@ async function fetchUpdate({ path, acceptedPath, timestamp }: Update) {
   const moduleMap = new Map<string, ModuleNamespace>()
   const isSelfUpdate = path === acceptedPath
 
-  // make sure we only import each dep once
-  const modulesToUpdate = new Set<string>()
-  if (isSelfUpdate) {
-    // self update - only update self
-    modulesToUpdate.add(path)
-  } else {
-    // dep update
-    for (const { deps } of mod.callbacks) {
-      deps.forEach((dep) => {
-        if (acceptedPath === dep) {
-          modulesToUpdate.add(dep)
-        }
-      })
-    }
-  }
-
   // determine the qualified callbacks before we re-import the modules
-  const qualifiedCallbacks = mod.callbacks.filter(({ deps }) => {
-    return deps.some((dep) => modulesToUpdate.has(dep))
-  })
-
-  await Promise.all(
-    Array.from(modulesToUpdate).map(async (dep) => {
-      const disposer = disposeMap.get(dep)
-      if (disposer) await disposer(dataMap.get(dep))
-      const [path, query] = dep.split(`?`)
-      try {
-        const newMod: ModuleNamespace = await import(
-          /* @vite-ignore */
-          base +
-            path.slice(1) +
-            `?import&t=${timestamp}${query ? `&${query}` : ''}`
-        )
-        moduleMap.set(dep, newMod)
-      } catch (e) {
-        warnFailedFetch(e, dep)
-      }
-    })
+  const qualifiedCallbacks = mod.callbacks.filter(({ deps }) =>
+    deps.includes(acceptedPath)
   )
 
+  if (isSelfUpdate || qualifiedCallbacks.length > 0) {
+    const dep = acceptedPath
+    const disposer = disposeMap.get(dep)
+    if (disposer) await disposer(dataMap.get(dep))
+    const [path, query] = dep.split(`?`)
+    try {
+      const newMod: ModuleNamespace = await import(
+        /* @vite-ignore */
+        base +
+          path.slice(1) +
+          `?import&t=${timestamp}${query ? `&${query}` : ''}`
+      )
+      moduleMap.set(dep, newMod)
+    } catch (e) {
+      warnFailedFetch(e, dep)
+    }
+  }
+
   return () => {
     for (const { deps, fn } of qualifiedCallbacks) {
       fn(deps.map((dep) => moduleMap.get(dep)))