fix(ssr): use tryNodeResolve instead of resolveFrom

Author: aleclarson

packages/vite/src/node/plugins/index.ts

@@ -14,6 +14,7 @@ import { modulePreloadPolyfillPlugin } from './modulePreloadPolyfill'
 import { webWorkerPlugin } from './worker'
 import { preAliasPlugin } from './preAlias'
 import { definePlugin } from './define'
+import { ssrRequireHookPlugin } from './ssrRequireHook'
 
 export async function resolvePlugins(
   config: ResolvedConfig,
@@ -42,6 +43,7 @@ export async function resolvePlugins(
       ssrConfig: config.ssr,
       asSrc: true
     }),
+    config.build.ssr ? ssrRequireHookPlugin(config) : null,
     htmlInlineScriptProxyPlugin(config),
     cssPlugin(config),
     config.esbuild !== false ? esbuildPlugin(config.esbuild) : null,

packages/vite/src/node/plugins/resolve.ts

@@ -67,6 +67,7 @@ export interface InternalResolveOptions extends ResolveOptions {
   tryPrefix?: string
   skipPackageJson?: boolean
   preferRelative?: boolean
+  preserveSymlinks?: boolean
   isRequire?: boolean
   // #3040
   // when the importer is a ts module,
@@ -305,7 +306,7 @@ export function resolvePlugin(baseOptions: InternalResolveOptions): Plugin {
 function tryFsResolve(
   fsPath: string,
   options: InternalResolveOptions,
-  preserveSymlinks: boolean,
+  preserveSymlinks?: boolean,
   tryIndex = true,
   targetWeb = true
 ): string | undefined {
@@ -426,7 +427,7 @@ function tryResolveFile(
   options: InternalResolveOptions,
   tryIndex: boolean,
   targetWeb: boolean,
-  preserveSymlinks: boolean,
+  preserveSymlinks?: boolean,
   tryPrefix?: string,
   skipPackageJson?: boolean
 ): string | undefined {
@@ -489,7 +490,7 @@ export const idToPkgMap = new Map<string, PackageData>()
 
 export function tryNodeResolve(
   id: string,
-  importer: string | undefined,
+  importer: string | null | undefined,
   options: InternalResolveOptions,
   targetWeb: boolean,
   server?: ViteDevServer,
@@ -522,14 +523,12 @@ export function tryNodeResolve(
     basedir = root
   }
 
-  const preserveSymlinks = !!server?.config.resolve.preserveSymlinks
-
   // nested node module, step-by-step resolve to the basedir of the nestedPath
   if (nestedRoot) {
-    basedir = nestedResolveFrom(nestedRoot, basedir, preserveSymlinks)
+    basedir = nestedResolveFrom(nestedRoot, basedir, options.preserveSymlinks)
   }
 
-  const pkg = resolvePackageData(pkgId, basedir, preserveSymlinks)
+  const pkg = resolvePackageData(pkgId, basedir, options.preserveSymlinks)
 
   if (!pkg) {
     return
@@ -541,9 +540,9 @@ export function tryNodeResolve(
         pkg,
         options,
         targetWeb,
-        preserveSymlinks
+        options.preserveSymlinks
       )
-    : resolvePackageEntry(id, pkg, options, targetWeb, preserveSymlinks)
+    : resolvePackageEntry(id, pkg, options, targetWeb, options.preserveSymlinks)
   if (!resolved) {
     return
   }
@@ -876,7 +875,7 @@ function resolveDeepImport(
   }: PackageData,
   options: InternalResolveOptions,
   targetWeb: boolean,
-  preserveSymlinks: boolean
+  preserveSymlinks?: boolean
 ): string | undefined {
   const cache = getResolvedCache(id, targetWeb)
   if (cache) {

packages/vite/src/node/plugins/ssrRequireHook.ts

@@ -0,0 +1,69 @@
+import MagicString from 'magic-string'
+import { ResolvedConfig } from '..'
+import { Plugin } from '../plugin'
+
+/**
+ * This plugin hooks into Node's module resolution algorithm at runtime,
+ * so that SSR builds can benefit from `resolve.dedupe` like they do
+ * in development.
+ */
+export function ssrRequireHookPlugin(config: ResolvedConfig): Plugin | null {
+  if (config.command !== 'build' || !config.resolve.dedupe?.length) {
+    return null
+  }
+  return {
+    name: 'vite:ssr-require-hook',
+    transform(code, id) {
+      const moduleInfo = this.getModuleInfo(id)
+      if (moduleInfo?.isEntry) {
+        const s = new MagicString(code)
+        s.prepend(
+          `;(${dedupeRequire.toString()})(${JSON.stringify(
+            config.resolve.dedupe
+          )});\n`
+        )
+        return {
+          code: s.toString(),
+          map: s.generateMap({
+            source: id
+          })
+        }
+      }
+    }
+  }
+}
+
+type NodeResolveFilename = (
+  request: string,
+  parent: NodeModule,
+  isMain: boolean,
+  options?: Record<string, any>
+) => string
+
+/** Respect the `resolve.dedupe` option in production SSR. */
+function dedupeRequire(dedupe: string[]) {
+  const Module = require('module') as { _resolveFilename: NodeResolveFilename }
+  const resolveFilename = Module._resolveFilename
+  Module._resolveFilename = function (request, parent, isMain, options) {
+    if (request[0] !== '.' && request[0] !== '/') {
+      const parts = request.split('/')
+      const pkgName = parts[0][0] === '@' ? parts[0] + '/' + parts[1] : parts[0]
+      if (dedupe.includes(pkgName)) {
+        // Use this module as the parent.
+        parent = module
+      }
+    }
+    return resolveFilename!(request, parent, isMain, options)
+  }
+}
+
+export function hookNodeResolve(
+  getResolver: (resolveFilename: NodeResolveFilename) => NodeResolveFilename
+): () => void {
+  const Module = require('module') as { _resolveFilename: NodeResolveFilename }
+  const prevResolver = Module._resolveFilename
+  Module._resolveFilename = getResolver(prevResolver)
+  return () => {
+    Module._resolveFilename = prevResolver
+  }
+}

packages/vite/src/node/ssr/ssrExternal.ts

@@ -32,7 +32,12 @@ export function resolveSSRExternal(
     seen.add(id)
   })
 
-  collectExternals(config.root, ssrExternals, seen)
+  collectExternals(
+    config.root,
+    config.resolve.preserveSymlinks,
+    ssrExternals,
+    seen
+  )
 
   for (const dep of knownImports) {
     // Assume external if not yet seen
@@ -59,6 +64,7 @@ export function resolveSSRExternal(
 // do we need to do this ahead of time or could we do it lazily?
 function collectExternals(
   root: string,
+  preserveSymlinks: boolean | undefined,
   ssrExternals: Set<string>,
   seen: Set<string>
 ) {
@@ -75,6 +81,7 @@ function collectExternals(
 
   const resolveOptions: InternalResolveOptions = {
     root,
+    preserveSymlinks,
     isProduction: false,
     isBuild: true
   }
@@ -132,7 +139,7 @@ function collectExternals(
     // or are there others like SystemJS / AMD that we'd need to handle?
     // for now, we'll just leave this as is
     else if (/\.m?js$/.test(esmEntry)) {
-      if (pkg.type === "module" || esmEntry.endsWith('.mjs')) {
+      if (pkg.type === 'module' || esmEntry.endsWith('.mjs')) {
         ssrExternals.add(id)
         continue
       }
@@ -145,7 +152,7 @@ function collectExternals(
   }
 
   for (const depRoot of depsToTrace) {
-    collectExternals(depRoot, ssrExternals, seen)
+    collectExternals(depRoot, preserveSymlinks, ssrExternals, seen)
   }
 }
 

packages/vite/src/node/ssr/ssrModuleLoader.ts

@@ -1,7 +1,7 @@
-import fs from 'fs'
 import path from 'path'
+import { Module } from 'module'
 import { pathToFileURL } from 'url'
-import { ViteDevServer } from '..'
+import { ViteDevServer } from '../server'
 import {
   dynamicImport,
   cleanUrl,
@@ -19,6 +19,8 @@ import {
   ssrDynamicImportKey
 } from './ssrTransform'
 import { transformRequest } from '../server/transformRequest'
+import { InternalResolveOptions, tryNodeResolve } from '../plugins/resolve'
+import { hookNodeResolve } from '../plugins/ssrRequireHook'
 
 interface SSRContext {
   global: typeof globalThis
@@ -96,13 +98,32 @@ async function instantiateModule(
   urlStack = urlStack.concat(url)
   const isCircular = (url: string) => urlStack.includes(url)
 
+  const {
+    isProduction,
+    resolve: { dedupe },
+    root
+  } = server.config
+
+  const resolveOptions: InternalResolveOptions = {
+    conditions: ['node'],
+    dedupe,
+    // Prefer CommonJS modules.
+    extensions: ['.js', '.mjs', '.ts', '.jsx', '.tsx', '.json'],
+    isBuild: true,
+    isProduction,
+    // Disable "module" condition.
+    isRequire: true,
+    mainFields: ['main'],
+    root
+  }
+
   // Since dynamic imports can happen in parallel, we need to
   // account for multiple pending deps and duplicate imports.
   const pendingDeps: string[] = []
 
   const ssrImport = async (dep: string) => {
     if (dep[0] !== '.' && dep[0] !== '/') {
-      return nodeImport(dep, mod.file, server.config)
+      return nodeImport(dep, mod.file!, resolveOptions)
     }
     dep = unwrapId(dep)
     if (!isCircular(dep) && !pendingImports.get(dep)?.some(isCircular)) {
@@ -185,21 +206,48 @@ async function instantiateModule(
 // In node@12+ we can use dynamic import to load CJS and ESM
 async function nodeImport(
   id: string,
-  importer: string | null,
-  config: ViteDevServer['config']
+  importer: string,
+  resolveOptions: InternalResolveOptions
 ) {
+  // Node's module resolution is hi-jacked so Vite can ensure the
+  // configured `resolve.dedupe` and `mode` options are respected.
+  const viteResolve = (id: string, importer: string) => {
+    const resolved = tryNodeResolve(id, importer, resolveOptions, false)
+    if (!resolved) {
+      const err: any = new Error(
+        `Cannot find module '${id}' imported from '${importer}'`
+      )
+      err.code = 'ERR_MODULE_NOT_FOUND'
+      throw err
+    }
+    return resolved.id
+  }
+
+  // When an ESM module imports an ESM dependency, this hook is *not* used.
+  const unhookNodeResolve = hookNodeResolve(
+    (nodeResolve) => (id, parent, isMain, options) =>
+      id[0] === '.' || isBuiltin(id)
+        ? nodeResolve(id, parent, isMain, options)
+        : viteResolve(id, parent.id)
+  )
+
   let url: string
   // `resolve` doesn't handle `node:` builtins, so handle them directly
   if (id.startsWith('node:') || isBuiltin(id)) {
     url = id
   } else {
-    url = resolve(id, importer, config.root, !!config.resolve.preserveSymlinks)
+    url = viteResolve(id, importer)
     if (usingDynamicImport) {
       url = pathToFileURL(url).toString()
     }
   }
-  const mod = await dynamicImport(url)
-  return proxyESM(id, mod)
+
+  try {
+    const mod = await dynamicImport(url)
+    return proxyESM(id, mod)
+  } finally {
+    unhookNodeResolve()
+  }
 }
 
 // rollup-style default import interop for cjs
@@ -216,25 +264,3 @@ function proxyESM(id: string, mod: any) {
     }
   })
 }
-
-const resolveCache = new Map<string, string>()
-
-function resolve(
-  id: string,
-  importer: string | null,
-  root: string,
-  preserveSymlinks: boolean
-) {
-  const key = id + importer + root
-  const cached = resolveCache.get(key)
-  if (cached) {
-    return cached
-  }
-  const resolveDir =
-    importer && fs.existsSync(cleanUrl(importer))
-      ? path.dirname(importer)
-      : root
-  const resolved = resolveFrom(id, resolveDir, preserveSymlinks, true)
-  resolveCache.set(key, resolved)
-  return resolved
-}