fix: replace import.meta.hot with undefined in the production (#11317)

Author: xunmi1

packages/vite/src/node/__tests__/plugins/define.spec.ts

@@ -41,17 +41,17 @@ describe('definePlugin', () => {
   })
 
   test('preserve import.meta.hot with override', async () => {
-    // assert that the default behavior is to replace import.meta.hot with false
+    // assert that the default behavior is to replace import.meta.hot with undefined
     const transform = await createDefinePluginTransform()
-    expect(await transform('const isHot = import.meta.hot;')).toBe(
-      'const isHot = false;',
+    expect(await transform('const hot = import.meta.hot;')).toBe(
+      'const hot = undefined;',
     )
     // assert that we can specify a user define to preserve import.meta.hot
     const overrideTransform = await createDefinePluginTransform({
       'import.meta.hot': 'import.meta.hot',
     })
-    expect(await overrideTransform('const isHot = import.meta.hot;')).toBe(
-      'const isHot = import.meta.hot;',
+    expect(await overrideTransform('const hot = import.meta.hot;')).toBe(
+      'const hot = import.meta.hot;',
     )
   })
 })

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

@@ -46,7 +46,7 @@ export function definePlugin(config: ResolvedConfig): Plugin {
       SSR: !!config.build.ssr,
     }
     // set here to allow override with config.define
-    importMetaKeys['import.meta.hot'] = `false`
+    importMetaKeys['import.meta.hot'] = `undefined`
     for (const key in env) {
       importMetaKeys[`import.meta.env.${key}`] = JSON.stringify(env[key])
     }

playground/hmr/counter/dep.ts

@@ -1,2 +1,4 @@
 // This file is never loaded
-import.meta.hot.accept(() => {})
+if (import.meta.hot) {
+  import.meta.hot.accept(() => {})
+}