fix(browser): fix import.meta.env define (#9205)

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

@@ -101,7 +101,8 @@ async function prepareTestEnvironment(options: PrepareOptions) {
 
   const state = getWorkerState()
 
-  state.metaEnv = import.meta.env
+  // @ts-expect-error replaced with `import.meta.env` by transform
+  state.metaEnv = __vitest_browser_import_meta_env_init__
   state.onCancel = onCancel
   state.ctx.rpc = rpc as any
   state.rpc = rpc as any

packages/browser/src/node/plugin.ts

@@ -622,6 +622,18 @@ body {
         }
       },
     },
+    {
+      name: 'vitest:browser:__vitest_browser_import_meta_env_init__',
+      transform: {
+        handler(code) {
+          // this transform runs after `vitest:meta-env-replacer` so that
+          // `import.meta.env` will be handled by Vite import analysis to match behavior.
+          if (code.includes('__vitest_browser_import_meta_env_init__')) {
+            return code.replace('__vitest_browser_import_meta_env_init__', 'import.meta.env')
+          }
+        },
+      },
+    },
   ]
 }
 

test/browser/test/env.test.ts

@@ -19,6 +19,10 @@ test('custom env', () => {
   expect(import.meta.env.CUSTOM_ENV).toBe('foo')
 })
 
+test('import.meta.env via define', () => {
+  expect(import.meta.env.DEFINE_CUSTOM_ENV).toBe('define-custom-env')
+})
+
 test('ignores import.meta.env in string literals', () => {
   expect('import.meta.env').toBe('import' + '.meta.env')
 })

test/browser/vitest.config.mts

@@ -52,6 +52,9 @@ export default defineConfig({
   optimizeDeps: {
     include: ['@vitest/cjs-lib', '@vitest/bundled-lib', 'react/jsx-dev-runtime'],
   },
+  define: {
+    'import.meta.env.DEFINE_CUSTOM_ENV': JSON.stringify('define-custom-env'),
+  },
   test: {
     include: ['test/**.test.{ts,js,tsx}'],
     includeSource: ['src/*.ts'],