fix(browser): allow immidiate reinvalidation of mocked dependencies

packages/browser/src/client/tester/msw.ts

@@ -27,6 +27,10 @@ export function createModuleMocker() {
         http.get(/.+/, async ({ request }) => {
           const path = cleanQuery(request.url.slice(location.origin.length))
           if (!mocks.has(path)) {
+            if (path.includes('/deps/')) {
+              return fetch(bypass(request))
+            }
+
             return passthrough()
           }
 
@@ -128,6 +132,20 @@ function passthrough() {
   })
 }
 
+function bypass(request: Request) {
+  const clonedRequest = request.clone()
+  clonedRequest.headers.set('x-msw-intention', 'bypass')
+  const cacheControl = clonedRequest.headers.get('cache-control')
+  if (cacheControl) {
+    clonedRequest.headers.set(
+      'cache-control',
+      // allow reinvalidation of the cache so mocks can be updated
+      cacheControl.replace(', immutable', ''),
+    )
+  }
+  return clonedRequest
+}
+
 const postfixRE = /[?#].*$/
 function cleanUrl(url: string): string {
   return url.replace(postfixRE, '')

packages/browser/src/node/plugin.ts

@@ -41,7 +41,7 @@ export default (browserServer: BrowserServer, base = '/'): Plugin[] => {
         })
         // eslint-disable-next-line prefer-arrow-callback
         server.middlewares.use(async function vitestBrowserMode(req, res, next) {
-          if (!req.url) {
+          if (!req.url || !browserServer.provider) {
             return next()
           }
           const url = new URL(req.url, 'http://localhost')

test/browser/cjs-lib/lib.d.ts

@@ -0,0 +1 @@
+export function lib(): string

test/browser/cjs-lib/lib.mjs

@@ -0,0 +1,3 @@
+export function lib() {
+  return 'original'
+}

test/browser/cjs-lib/package.json

@@ -2,6 +2,10 @@
   "name": "@vitest/cjs-lib",
   "type": "commonjs",
   "exports": {
-    "default": "./index.js"
+    "./lib": {
+      "types": "./lib.d.ts",
+      "default": "./lib.mjs"
+    },
+    ".": "./index.js"
   }
 }

test/browser/fixtures/mocking-watch/1_mocked-on-watch-change.test.ts

@@ -0,0 +1,12 @@
+import { lib } from '@vitest/cjs-lib/lib'
+import { vi, test, expect } from 'vitest'
+
+vi.mock(import('@vitest/cjs-lib/lib'), () => {
+  return {
+    lib: vi.fn(() => 'mocked')
+  }
+})
+
+test('mocks correctly', () => {
+  expect(lib()).toBe('mocked')
+})

test/browser/fixtures/mocking-watch/2_not-mocked-import.test.ts

@@ -0,0 +1,6 @@
+import { lib } from '@vitest/cjs-lib/lib'
+import { test, expect } from 'vitest'
+
+test('not mocked', () => {
+  expect(lib()).toBe('original')
+})

test/browser/fixtures/mocking-watch/vitest.config.ts

@@ -0,0 +1,22 @@
+import { fileURLToPath } from 'node:url'
+import { defineConfig } from 'vitest/config'
+
+const provider = process.env.PROVIDER || 'playwright'
+const name =
+  process.env.BROWSER || (provider === 'playwright' ? 'chromium' : 'chrome')
+
+export default defineConfig({
+  optimizeDeps: {
+    include: ['@vitest/cjs-lib', '@vitest/cjs-lib/lib'],
+  },
+  cacheDir: fileURLToPath(new URL("./node_modules/.vite", import.meta.url)),
+  test: {
+    browser: {
+      fileParallelism: false,
+      enabled: true,
+      provider,
+      name,
+      headless: true,
+    },
+  },
+})

test/browser/fixtures/mocking/vitest.config.ts

@@ -1,3 +1,4 @@
+import { fileURLToPath } from 'node:url'
 import { defineConfig } from 'vitest/config'
 
 const provider = process.env.PROVIDER || 'playwright'
@@ -9,6 +10,7 @@ export default defineConfig({
     include: ['@vitest/cjs-lib'],
     needsInterop: ['@vitest/cjs-lib'],
   },
+  cacheDir: fileURLToPath(new URL("./node_modules/.vite", import.meta.url)),
   test: {
     browser: {
       enabled: true,

test/browser/package.json

@@ -10,6 +10,7 @@
     "test:safaridriver": "PROVIDER=webdriverio BROWSER=safari pnpm run test:unit",
     "test-fixtures": "vitest",
     "test-mocking": "vitest --root ./fixtures/mocking",
+    "test-mocking-watch": "vitest --root ./fixtures/mocking-watch",
     "test-snapshots": "vitest --root ./fixtures/update-snapshot",
     "coverage": "vitest --coverage.enabled --coverage.provider=istanbul --browser.headless=yes",
     "test:browser:preview": "PROVIDER=preview vitest",

test/browser/specs/mocking.test.ts

@@ -1,5 +1,5 @@
-import { expect, onTestFailed, test } from 'vitest'
-import { runVitest } from '../../test-utils'
+import { expect, onTestFailed, onTestFinished, test } from 'vitest'
+import { editFile, runVitest } from '../../test-utils'
 
 test.each([true, false])('mocking works correctly - isolated %s', async (isolate) => {
   const result = await runVitest({
@@ -26,3 +26,29 @@ test.each([true, false])('mocking works correctly - isolated %s', async (isolate
   expect(result.stdout).toContain('mocked-do-mock-factory.test.ts')
   expect(result.exitCode).toBe(0)
 })
+
+test('mocking dependency correctly invalidates it on rerun', async () => {
+  const { vitest, ctx } = await runVitest({
+    root: 'fixtures/mocking-watch',
+    watch: true,
+  })
+  onTestFinished(async () => {
+    await ctx.close()
+    await ctx.closingPromise
+  })
+
+  await vitest.waitForStdout('Waiting for file changes...')
+
+  expect(vitest.stderr).toBe('')
+  expect(vitest.stdout).toContain('1_mocked-on-watch-change.test.ts')
+  expect(vitest.stdout).toContain('2_not-mocked-import.test.ts')
+
+  vitest.resetOutput()
+  editFile('./fixtures/mocking-watch/1_mocked-on-watch-change.test.ts', content => `${content}\n`)
+
+  await vitest.waitForStdout('Waiting for file changes...')
+
+  expect(vitest.stderr).toBe('')
+  expect(vitest.stdout).toContain('1_mocked-on-watch-change.test.ts')
+  expect(vitest.stdout).not.toContain('2_not-mocked-import.test.ts')
+})