fix(build): deterministic local search indexing and non-blocking initial scan (closes #4081)

src/node/plugins/localSearchPlugin.ts

@@ -2,7 +2,6 @@ import { createDebug } from 'obug'
 import fs from 'fs-extra'
 import MiniSearch from 'minisearch'
 import path from 'node:path'
-import pMap from 'p-map'
 import type { Plugin, ViteDevServer } from 'vite'
 import type { SiteConfig } from '../config'
 import type { DefaultTheme } from '../defaultTheme'
@@ -81,9 +80,10 @@ export async function localSearchPlugin(
   }
 
   let server: ViteDevServer | undefined
+  let pending: Promise<void>
 
   function onIndexUpdated() {
-    if (server) {
+    if (!server) return
     server.moduleGraph.onFileChange(LOCAL_SEARCH_INDEX_REQUEST_PATH)
     // HMR
     const mod = server.moduleGraph.getModuleById(
@@ -102,7 +102,6 @@ export async function localSearchPlugin(
       ]
     })
   }
-  }
 
   function getDocId(file: string) {
     let relFile = slash(path.relative(siteConfig.srcDir, file))
@@ -142,9 +141,9 @@ export async function localSearchPlugin(
 
   async function scanForBuild() {
     debug('🔍️ Indexing files for search...')
-    await pMap(siteConfig.pages, indexFile, {
-      concurrency: siteConfig.buildConcurrency
-    })
+    for (const page of siteConfig.pages) {
+      await indexFile(page)
+    }
     debug('✅ Indexing finished...')
   }
 
@@ -161,10 +160,9 @@ export async function localSearchPlugin(
       }
     }),
 
-    async configureServer(_server) {
+    configureServer(_server) {
       server = _server
-      await scanForBuild()
-      onIndexUpdated()
+      pending = scanForBuild().then(onIndexUpdated)
     },
 
     resolveId(id) {
@@ -175,6 +173,7 @@ export async function localSearchPlugin(
 
     async load(id) {
       if (id === LOCAL_SEARCH_INDEX_REQUEST_PATH) {
+        await pending
         if (process.env.NODE_ENV === 'production') {
           await scanForBuild()
         }
@@ -188,6 +187,7 @@ export async function localSearchPlugin(
         }
         return `export default {${records.join(',')}}`
       } else if (id.startsWith(LOCAL_SEARCH_INDEX_REQUEST_PATH)) {
+        await pending
         return `export default ${JSON.stringify(
           JSON.stringify(
             indexByLocales.get(