fix(vite-node): externalize network imports (#4987)

eslint.config.js

@@ -13,6 +13,7 @@ export default antfu(
       'test/core/src/self',
       'test/workspaces/results.json',
       'test/reporters/fixtures/with-syntax-error.test.js',
+      'test/network-imports/public/slash@3.0.0.js',
       'examples/**/mockServiceWorker.js',
     ],
   },

package.json

@@ -27,7 +27,7 @@
     "test:run": "vitest run -r test/core",
     "test:all": "CI=true pnpm -r --stream run test --allowOnly",
     "test:ci": "CI=true pnpm -r --stream --filter !test-browser --filter !test-esm --filter !test-browser run test --allowOnly",
-    "test:ci:vm-threads": "CI=true pnpm -r --stream --filter !test-coverage --filter !test-single-thread --filter !test-browser --filter !test-esm --filter !test-browser --filter !example-react-testing-lib-msw run test --allowOnly --pool vmThreads",
+    "test:ci:vm-threads": "CI=true pnpm -r --stream --filter !test-coverage --filter !test-single-thread --filter !test-browser --filter !test-esm --filter !test-network-imports --filter !test-browser --filter !example-react-testing-lib-msw run test --allowOnly --pool vmThreads",
     "test:ci:no-threads": "CI=true pnpm -r --stream --filter !test-vm-threads --filter !test-coverage --filter !test-watch --filter !test-bail --filter !test-esm --filter !test-browser run test --allowOnly --pool forks",
     "typecheck": "tsc -p tsconfig.check.json --noEmit",
     "typecheck:why": "tsc -p tsconfig.check.json --noEmit --explainFiles > explainTypes.txt",

packages/vite-node/src/externalize.ts

@@ -95,8 +95,9 @@ async function _shouldExternalize(
     return id
 
   // data: should be processed by native import,
-  // since it is a feature of ESM
-  if (id.startsWith('data:'))
+  // since it is a feature of ESM.
+  // also externalize network imports since nodejs allows it when --experimental-network-imports
+  if (id.startsWith('data:') || /^(https?:)?\/\//.test(id))
     return id
 
   id = patchWindowsImportPath(id)

test/network-imports/package.json

@@ -0,0 +1,11 @@
+{
+  "name": "@vitest/test-network-imports",
+  "type": "module",
+  "private": true,
+  "scripts": {
+    "test": "vitest"
+  },
+  "devDependencies": {
+    "vitest": "workspace:*"
+  }
+}

test/network-imports/test/basic.test.ts

@@ -0,0 +1,11 @@
+import { expect, test } from 'vitest'
+
+// @ts-expect-error network imports
+import slash from 'http://localhost:9602/slash@3.0.0.js'
+
+// test without local server
+// import slash from 'https://esm.sh/slash@3.0.0'
+
+test('network imports', () => {
+  expect(slash('foo\\bar')).toBe('foo/bar')
+})

test/network-imports/vitest.config.ts

@@ -0,0 +1,24 @@
+import { defineConfig } from 'vitest/config'
+
+export default defineConfig({
+  test: {
+    poolOptions: {
+      threads: {
+        execArgv: ['--experimental-network-imports'],
+      },
+      forks: {
+        execArgv: ['--experimental-network-imports'],
+      },
+      // not supported?
+      //   FAIL  test/basic.test.ts [ test/basic.test.ts ]
+      //   Error: ENOENT: no such file or directory, open 'http://localhost:9602/slash@3.0.0.js'
+      //    ❯ Object.openSync node:fs:596:3
+      //    ❯ readFileSync node:fs:464:35
+      vmThreads: {
+        execArgv: ['--experimental-network-imports'],
+      },
+    },
+    // let vite serve public/slash@3.0.0.js
+    api: 9602,
+  },
+})