fix: allow inlining fully dynamic import

packages/vitest/src/node/environments/fetchModule.ts

@@ -12,6 +12,7 @@ import { isExternalUrl, unwrapId } from '@vitest/utils/helpers'
 import { join } from 'pathe'
 import { fetchModule } from 'vite'
 import { hash } from '../hash'
+import { normalizeResolvedIdToUrl } from './normalizeUrl'
 
 const saveCachePromises = new Map<string, Promise<FetchResult>>()
 const readFilePromises = new Map<string, Promise<string | null>>()
@@ -54,6 +55,14 @@ class ModuleFetcher {
       return { externalize: url, type: 'network' }
     }
 
+    // handle unresolved id of dynamic import skipped by Vite import analysis
+    if (url[0] !== '/') {
+      const resolved = await environment.pluginContainer.resolveId(url, importer)
+      if (resolved) {
+        url = normalizeResolvedIdToUrl(environment, resolved.id)
+      }
+    }
+
     const moduleGraphModule = await environment.moduleGraph.ensureEntryFromUrl(unwrapId(url))
     const cached = !!moduleGraphModule.transformResult
 

packages/vitest/src/runtime/moduleRunner/moduleEvaluator.ts

@@ -322,21 +322,11 @@ export class VitestModuleEvaluator implements ModuleEvaluator {
         ? vm.runInContext(wrappedCode, this.vm.context, options)
         : vm.runInThisContext(wrappedCode, options)
 
-      const dynamicRequest = async (dep: string, options: ImportCallOptions) => {
-        dep = String(dep)
-        // TODO: support more edge cases?
-        // vite doesn't support dynamic modules by design, but we have to
-        if (dep[0] === '#') {
-          return context[ssrDynamicImportKey](wrapId(dep), options)
-        }
-        return context[ssrDynamicImportKey](dep, options)
-      }
-
       await initModule(
         context[ssrModuleExportsKey],
         context[ssrImportMetaKey],
         context[ssrImportKey],
-        dynamicRequest,
+        context[ssrDynamicImportKey],
         context[ssrExportAllKey],
         // vite 7 support, remove when vite 7+ is supported
         (context as any).__vite_ssr_exportName__

test/config/deps/test-dep-virtual/index.js

@@ -0,0 +1 @@
+export * from 'virtual:test'

test/config/deps/test-dep-virtual/package.json

@@ -0,0 +1,6 @@
+{
+  "name": "@vitejs/test-dep-virtual",
+  "type": "module",
+  "private": true,
+  "exports": "./index.js"
+}

test/config/fixtures/external/dynamic/basic.test.ts

@@ -0,0 +1,7 @@
+import { expect, it } from "vitest";
+
+it("basic", async () => {
+  const getId = () => "@vitejs/test-dep-virtual";
+  const mod = await import(getId());
+  expect(mod.test).toBe("ok");
+});

test/config/fixtures/external/dynamic/vitest.config.ts

@@ -0,0 +1,22 @@
+import { defineConfig } from "vitest/config";
+
+export default defineConfig({
+  ssr: {
+    noExternal: ["@vitejs/test-dep-virtual"],
+  },
+  plugins: [
+    {
+      name: 'test-virtual',
+      resolveId(source) {
+        if (source === 'virtual:test') {
+          return '\0' + source;
+        }
+      },
+      load(id) {
+        if (id === '\0virtual:test') {
+          return `export const test = "ok";`;
+        }
+      }
+    }
+  ],
+});

test/config/package.json

@@ -7,6 +7,7 @@
   },
   "devDependencies": {
     "@test/test-dep-config": "link:./deps/test-dep-config",
+    "@vitejs/test-dep-virtual": "file:./deps/test-dep-virtual",
     "@vitest/browser-playwright": "workspace:*",
     "@vitest/browser-preview": "workspace:*",
     "@vitest/browser-webdriverio": "workspace:*",

test/config/test/external.test.ts

@@ -0,0 +1,15 @@
+import { expect, it } from 'vitest'
+import { runVitest } from '../../test-utils'
+
+it('can inline fully dynamic import', async () => {
+  const { errorTree } = await runVitest({
+    root: 'fixtures/external/dynamic',
+  })
+  expect(errorTree()).toMatchInlineSnapshot(`
+    {
+      "basic.test.ts": {
+        "basic": "passed",
+      },
+    }
+  `)
+})