fix(optimize-deps): ensure consistent browserHash between in-memory and persisted metadata

infiton · infiton · commit a1d485c4a4a7 · 2025-10-09T19:45:12.000-04:00
When the dev server restarts mid–asset waterfall and loads cached
`_metadata.json`, inconsistent `browserHash` values can cause duplicate
instances of the same dependency to be loaded (e.g. multiple React copies).

This patch sets the `browserHash` eagerly in memory before resolving
`scanProcessing`, ensuring both the in-memory metadata and the persisted
metadata use the same value.
diff --git a/packages/vite/src/node/__tests__/external.spec.ts b/packages/vite/src/node/__tests__/external.spec.ts
@@ -7,12 +7,12 @@ import { PartialEnvironment } from '../baseEnvironment'
 describe('createIsConfiguredAsExternal', () => {
   test('default', async () => {
     const isExternal = await createIsExternal()
-    expect(isExternal('@vitejs/cjs-ssr-dep')).toBe(false)
+    expect(await isExternal('@vitejs/cjs-ssr-dep')).toBe(false)
   })
 
   test('force external', async () => {
     const isExternal = await createIsExternal(true)
-    expect(isExternal('@vitejs/cjs-ssr-dep')).toBe(true)
+    expect(await isExternal('@vitejs/cjs-ssr-dep')).toBe(true)
   })
 })
 
diff --git a/packages/vite/src/node/config.ts b/packages/vite/src/node/config.ts
@@ -1953,32 +1953,34 @@ async function bundleConfigFile(
         name: 'externalize-deps',
         setup(build) {
           const packageCache = new Map()
-          const resolveByViteResolver = (
+          const resolveByViteResolver = async (
             id: string,
             importer: string,
             isRequire: boolean,
           ) => {
-            return tryNodeResolve(id, importer, {
-              root: path.dirname(fileName),
-              isBuild: true,
-              isProduction: true,
-              preferRelative: false,
-              tryIndex: true,
-              mainFields: [],
-              conditions: [
-                'node',
-                ...(isModuleSyncConditionEnabled ? ['module-sync'] : []),
-              ],
-              externalConditions: [],
-              external: [],
-              noExternal: [],
-              dedupe: [],
-              extensions: configDefaults.resolve.extensions,
-              preserveSymlinks: false,
-              packageCache,
-              isRequire,
-              builtins: nodeLikeBuiltins,
-            })?.id
+            return (
+              await tryNodeResolve(id, importer, {
+                root: path.dirname(fileName),
+                isBuild: true,
+                isProduction: true,
+                preferRelative: false,
+                tryIndex: true,
+                mainFields: [],
+                conditions: [
+                  'node',
+                  ...(isModuleSyncConditionEnabled ? ['module-sync'] : []),
+                ],
+                externalConditions: [],
+                external: [],
+                noExternal: [],
+                dedupe: [],
+                extensions: configDefaults.resolve.extensions,
+                preserveSymlinks: false,
+                packageCache,
+                isRequire,
+                builtins: nodeLikeBuiltins,
+              })
+            )?.id
           }
 
           // externalize bare imports
@@ -2003,16 +2005,16 @@ async function bundleConfigFile(
               const isImport = isESM || kind === 'dynamic-import'
               let idFsPath: string | undefined
               try {
-                idFsPath = resolveByViteResolver(id, importer, !isImport)
+                idFsPath = await resolveByViteResolver(id, importer, !isImport)
               } catch (e) {
                 if (!isImport) {
                   let canResolveWithImport = false
                   try {
-                    canResolveWithImport = !!resolveByViteResolver(
+                    canResolveWithImport = !!(await resolveByViteResolver(
                       id,
                       importer,
                       false,
-                    )
+                    ))
                   } catch {}
                   if (canResolveWithImport) {
                     throw new Error(
diff --git a/packages/vite/src/node/external.ts b/packages/vite/src/node/external.ts
@@ -16,25 +16,25 @@ const debug = createDebugger('vite:external')
 
 const isExternalCache = new WeakMap<
   Environment,
-  (id: string, importer?: string) => boolean
+  (id: string, importer?: string) => Promise<boolean>
 >()
 
-export function shouldExternalize(
+export async function shouldExternalize(
   environment: Environment,
   id: string,
   importer: string | undefined,
-): boolean {
+): Promise<boolean> {
   let isExternal = isExternalCache.get(environment)
   if (!isExternal) {
     isExternal = createIsExternal(environment)
     isExternalCache.set(environment, isExternal)
   }
-  return isExternal(id, importer)
+  return await isExternal(id, importer)
 }
 
 export function createIsConfiguredAsExternal(
   environment: PartialEnvironment,
-): (id: string, importer?: string) => boolean {
+): (id: string, importer?: string) => Promise<boolean> {
   const { config } = environment
   const { root, resolve } = config
   const { external, noExternal } = resolve
@@ -53,16 +53,16 @@ export function createIsConfiguredAsExternal(
     conditions: targetConditions,
   }
 
-  const isExternalizable = (
+  const isExternalizable = async (
     id: string,
     importer: string | undefined,
     configuredAsExternal: boolean,
-  ): boolean => {
+  ): Promise<boolean> => {
     if (!bareImportRE.test(id) || id.includes('\0')) {
       return false
     }
     try {
-      const resolved = tryNodeResolve(
+      const resolved = await tryNodeResolve(
         id,
         // Skip passing importer in build to avoid externalizing non-hoisted dependencies
         // unresolvable from root (which would be unresolvable from output bundles also)
@@ -91,7 +91,7 @@ export function createIsConfiguredAsExternal(
 
   // Returns true if it is configured as external, false if it is filtered
   // by noExternal and undefined if it isn't affected by the explicit config
-  return (id: string, importer?: string) => {
+  return async (id: string, importer?: string) => {
     if (
       // If this id is defined as external, force it as external
       // Note that individual package entries are allowed in `external`
@@ -120,26 +120,26 @@ export function createIsConfiguredAsExternal(
     }
     // If external is true, all will be externalized by default, regardless if
     // it's a linked package
-    return isExternalizable(id, importer, external === true)
+    return await isExternalizable(id, importer, external === true)
   }
 }
 
 function createIsExternal(
   environment: Environment,
-): (id: string, importer?: string) => boolean {
+): (id: string, importer?: string) => Promise<boolean> {
   const processedIds = new Map<string, boolean>()
 
   const isConfiguredAsExternal = createIsConfiguredAsExternal(environment)
 
-  return (id: string, importer?: string) => {
+  return async (id: string, importer?: string) => {
     if (processedIds.has(id)) {
       return processedIds.get(id)!
     }
     let isExternal = false
     if (id[0] !== '.' && !path.isAbsolute(id)) {
       isExternal =
         isBuiltin(environment.config.resolve.builtins, id) ||
-        isConfiguredAsExternal(id, importer)
+        (await isConfiguredAsExternal(id, importer))
     }
     processedIds.set(id, isExternal)
     return isExternal
diff --git a/packages/vite/src/node/optimizer/index.ts b/packages/vite/src/node/optimizer/index.ts
@@ -1330,11 +1330,11 @@ function getDepHash(environment: Environment): {
   }
 }
 
-function getOptimizedBrowserHash(
+export function getOptimizedBrowserHash(
   hash: string,
   deps: Record<string, string>,
   timestamp = '',
-) {
+): string {
   return getHash(hash + JSON.stringify(deps) + timestamp)
 }
 
diff --git a/packages/vite/src/node/optimizer/optimizer.ts b/packages/vite/src/node/optimizer/optimizer.ts
@@ -15,6 +15,7 @@ import {
   depsLogString,
   discoverProjectDependencies,
   extractExportsData,
+  getOptimizedBrowserHash,
   getOptimizedDepPath,
   initDepsOptimizerMetadata,
   loadCachedDepOptimizationMetadata,
@@ -237,6 +238,20 @@ export function createDepsOptimizer(
               const knownDeps = prepareKnownDeps()
               startNextDiscoveredBatch()
 
+              // Ensure consistent browserHash between in-memory and persisted metadata.
+              // By setting it eagerly here (before scanProcessing resolves), both the
+              // current server and any subsequent server loading _metadata.json will
+              // produce the same browserHash for these deps, avoiding mismatches during
+              // mid-load restarts.
+              metadata.browserHash = getOptimizedBrowserHash(
+                metadata.hash,
+                depsFromOptimizedDepInfo(knownDeps),
+              )
+
+              for (const dep of Object.keys(metadata.discovered)) {
+                metadata.discovered[dep].browserHash = metadata.browserHash
+              }
+
               // For dev, we run the scanner and the first optimization
               // run on the background
               optimizationResult = runOptimizeDeps(environment, knownDeps)
diff --git a/packages/vite/src/node/plugins/importAnalysis.ts b/packages/vite/src/node/plugins/importAnalysis.ts
@@ -331,6 +331,8 @@ export function importAnalysisPlugin(config: ResolvedConfig): Plugin {
           depsOptimizer &&
           moduleListContains(depsOptimizer.options.exclude, url)
         ) {
+          // Wait for scanning to complete to ensure stable browserHash and metadata
+          // This prevents inconsistent hashes between in-memory and persisted metadata
           await depsOptimizer.scanProcessing
 
           // if the dependency encountered in the optimized file was excluded from the optimization
@@ -520,7 +522,7 @@ export function importAnalysisPlugin(config: ResolvedConfig): Plugin {
             }
             // skip ssr externals and builtins
             if (ssr && !matchAlias(specifier)) {
-              if (shouldExternalize(environment, specifier, importer)) {
+              if (await shouldExternalize(environment, specifier, importer)) {
                 return
               }
               if (isBuiltin(environment.config.resolve.builtins, specifier)) {
diff --git a/packages/vite/src/node/plugins/resolve.ts b/packages/vite/src/node/plugins/resolve.ts
diff --git a/packages/vite/src/node/ssr/fetchModule.ts b/packages/vite/src/node/ssr/fetchModule.ts
diff --git a/playground/optimize-deps/__tests__/optimize-deps.spec.ts b/playground/optimize-deps/__tests__/optimize-deps.spec.ts

Original file line number	Diff line number	Diff line change
`@@ -1330,11 +1330,11 @@ function getDepHash(environment: Environment): {`
`1330`	`1330`	`}`
`1331`	`1331`	`}`
`1332`	`1332`
`1333`		`-function getOptimizedBrowserHash(`
	`1333`	`+export function getOptimizedBrowserHash(`
`1334`	`1334`	`hash: string,`
`1335`	`1335`	`deps: Record<string, string>,`
`1336`	`1336`	`timestamp = '',`
`1337`		`-) {`
	`1337`	`+): string {`
`1338`	`1338`	`return getHash(hash + JSON.stringify(deps) + timestamp)`
`1339`	`1339`	`}`
`1340`	`1340`