fix(nuxt): use useId for client-fallback component uid (#30314)

packages/nuxt/src/app/components/client-fallback.client.ts

@@ -1,13 +1,10 @@
-import { createElementBlock, defineComponent, onMounted, ref } from 'vue'
+import { createElementBlock, defineComponent, onMounted, ref, useId } from 'vue'
 import { useState } from '../composables/state'
 
 export default defineComponent({
   name: 'NuxtClientFallback',
   inheritAttrs: false,
   props: {
-    uid: {
-      type: String,
-    },
     fallbackTag: {
       type: String,
       default: () => 'div',
@@ -31,7 +28,7 @@ export default defineComponent({
   setup (props, ctx) {
     const mounted = ref(false)
     // This is deliberate - `uid` should not be provided by user but by a transform plugin and will not be reactive.
-    const ssrFailed = useState(`${props.uid}`)
+    const ssrFailed = useState(useId())
 
     if (ssrFailed.value) {
       onMounted(() => { mounted.value = true })

packages/nuxt/src/app/components/client-fallback.server.ts

@@ -1,18 +1,14 @@
-import { defineComponent, getCurrentInstance, onErrorCaptured, ref } from 'vue'
+import { defineComponent, getCurrentInstance, onErrorCaptured, ref, useId } from 'vue'
 import { ssrRenderAttrs, ssrRenderSlot, ssrRenderVNode } from 'vue/server-renderer'
 
 import { isPromise } from '@vue/shared'
 import { useState } from '../composables/state'
-import { useNuxtApp } from '../nuxt'
 import { createBuffer } from './utils'
 
 const NuxtClientFallbackServer = defineComponent({
   name: 'NuxtClientFallback',
   inheritAttrs: false,
   props: {
-    uid: {
-      type: String,
-    },
     fallbackTag: {
       type: String,
       default: () => 'div',
@@ -37,11 +33,10 @@ const NuxtClientFallbackServer = defineComponent({
       return true
     },
   },
-  async setup (props, ctx) {
+  async setup (_, ctx) {
     const vm = getCurrentInstance()
     const ssrFailed = ref(false)
-    const nuxtApp = useNuxtApp()
-    const error = useState<boolean | undefined>(`${props.uid}`)
+    const error = useState<boolean | undefined>(useId())
 
     onErrorCaptured((err) => {
       error.value = true
@@ -68,7 +63,7 @@ const NuxtClientFallbackServer = defineComponent({
       return { ssrFailed, ssrVNodes }
     } catch (ssrError) {
       // catch in dev
-      nuxtApp.runWithContext(() => useState(`${props.uid}`, () => true))
+      error.value = true
       ctx.emit('ssr-error', ssrError)
       return { ssrFailed: true, ssrVNodes: [] }
     }

packages/nuxt/src/components/module.ts

@@ -7,7 +7,6 @@ import { distDir } from '../dirs'
 import { componentNamesTemplate, componentsIslandsTemplate, componentsMetadataTemplate, componentsPluginTemplate, componentsTypeTemplate } from './templates'
 import { scanComponents } from './scan'
 
-import { ClientFallbackAutoIdPlugin } from './plugins/client-fallback-auto-id'
 import { LoaderPlugin } from './plugins/loader'
 import { ComponentsChunkPlugin, IslandsTransformPlugin } from './plugins/islands-transform'
 import { TransformPlugin } from './plugins/transform'
@@ -220,11 +219,6 @@ export default defineNuxtModule<ComponentsOptions>({
       addBuildPlugin(TreeShakeTemplatePlugin({ sourcemap: !!nuxt.options.sourcemap.server, getComponents }), { client: false })
     }
 
-    if (nuxt.options.experimental.clientFallback) {
-      addBuildPlugin(ClientFallbackAutoIdPlugin({ sourcemap: !!nuxt.options.sourcemap.client, rootDir: nuxt.options.rootDir }), { server: false })
-      addBuildPlugin(ClientFallbackAutoIdPlugin({ sourcemap: !!nuxt.options.sourcemap.server, rootDir: nuxt.options.rootDir }), { client: false })
-    }
-
     const sharedLoaderOptions = {
       getComponents,
       serverComponentRuntime,

packages/nuxt/src/components/plugins/client-fallback-auto-id.ts

@@ -1,55 +0,0 @@
-import { createUnplugin } from 'unplugin'
-import type { ComponentsOptions } from '@nuxt/schema'
-import MagicString from 'magic-string'
-import { isAbsolute, relative } from 'pathe'
-import { hash } from 'ohash'
-import { isVue } from '../../core/utils'
-
-interface LoaderOptions {
-  sourcemap?: boolean
-  transform?: ComponentsOptions['transform']
-  rootDir: string
-}
-const CLIENT_FALLBACK_RE = /<(?:NuxtClientFallback|nuxt-client-fallback)(?: [^>]*)?>/
-const CLIENT_FALLBACK_GLOBAL_RE = /<(NuxtClientFallback|nuxt-client-fallback)( [^>]*)?>/g
-const UID_RE = / :?uid=/
-export const ClientFallbackAutoIdPlugin = (options: LoaderOptions) => createUnplugin(() => {
-  const exclude = options.transform?.exclude || []
-  const include = options.transform?.include || []
-
-  return {
-    name: 'nuxt:client-fallback-auto-id',
-    enforce: 'pre',
-    transformInclude (id) {
-      if (exclude.some(pattern => pattern.test(id))) {
-        return false
-      }
-      if (include.some(pattern => pattern.test(id))) {
-        return true
-      }
-      return isVue(id)
-    },
-    transform (code, id) {
-      if (!CLIENT_FALLBACK_RE.test(code)) { return }
-
-      const s = new MagicString(code)
-      const relativeID = isAbsolute(id) ? relative(options.rootDir, id) : id
-      let count = 0
-
-      s.replace(CLIENT_FALLBACK_GLOBAL_RE, (full, name, attrs) => {
-        count++
-        if (UID_RE.test(attrs)) { return full }
-        return `<${name} :uid="'${hash(relativeID)}' + JSON.stringify($props) + '${count}'"  ${attrs ?? ''}>`
-      })
-
-      if (s.hasChanged()) {
-        return {
-          code: s.toString(),
-          map: options.sourcemap
-            ? s.generateMap({ hires: true })
-            : undefined,
-        }
-      }
-    },
-  }
-})