fix(nuxt): use payload error state as source of truth (#6389)

packages/nuxt/src/app/composables/error.ts

@@ -1,10 +1,8 @@
 import { createError as _createError, H3Error } from 'h3'
-import { useNuxtApp, useState } from '#app'
+import { toRef } from 'vue'
+import { useNuxtApp } from '#app'
 
-export const useError = () => {
+export const useError = () => toRef(useNuxtApp().payload, 'error')
-  const nuxtApp = useNuxtApp()
-  return useState('error', () => process.server ? nuxtApp.ssrContext.error : nuxtApp.payload.error)
-}
 
 export interface NuxtError extends H3Error {}
 
@@ -14,12 +12,8 @@ export const showError = (_err: string | Error | Partial<NuxtError>) => {
   try {
     const nuxtApp = useNuxtApp()
     nuxtApp.callHook('app:error', err)
-    if (process.server) {
-      nuxtApp.ssrContext.error = nuxtApp.ssrContext.error || err
-    } else {
     const error = useError()
     error.value = error.value || err
-    }
   } catch {
     throw err
   }

packages/nuxt/src/app/entry.ts

@@ -35,7 +35,7 @@ if (process.server) {
       await nuxt.hooks.callHook('app:created', vueApp)
     } catch (err) {
       await nuxt.callHook('app:error', err)
-      ssrContext.error = ssrContext.error || err
+      nuxt.payload.error = nuxt.payload.error || err
     }
 
     return vueApp

packages/nuxt/src/app/nuxt.ts

@@ -59,7 +59,8 @@ interface _NuxtApp {
     res?: CompatibilityEvent['res']
     runtimeConfig: RuntimeConfig
     noSSR: boolean
-    error?: any
+    /** whether we are rendering an SSR error */
+    error?: boolean
     nuxt: _NuxtApp
     payload: _NuxtApp['payload']
     teleports?: Record<string, string>
@@ -70,6 +71,14 @@ interface _NuxtApp {
     data?: Record<string, any>
     state?: Record<string, any>
     rendered?: Function
+    error?: Error | {
+      url: string
+      statusCode: string
+      statusMessage: string
+      message: string
+      description: string
+      data?: any
+    }
     [key: string]: any
   }
 
@@ -119,19 +128,19 @@ export function createNuxtApp (options: CreateOptions) {
   defineGetter(nuxtApp.vueApp, '$nuxt', nuxtApp)
   defineGetter(nuxtApp.vueApp.config.globalProperties, '$nuxt', nuxtApp)
 
+  if (process.server) {
     // Expose nuxt to the renderContext
     if (nuxtApp.ssrContext) {
       nuxtApp.ssrContext.nuxt = nuxtApp
     }
-
-  if (process.server) {
     // Expose to server renderer to create window.__NUXT__
     nuxtApp.ssrContext = nuxtApp.ssrContext || {} as any
-    nuxtApp.ssrContext.payload = nuxtApp.payload
+    if (nuxtApp.ssrContext.payload) {
+      Object.assign(nuxtApp.payload, nuxtApp.ssrContext.payload)
     }
+    nuxtApp.ssrContext.payload = nuxtApp.payload
 
     // Expose client runtime-config to the payload
-  if (process.server) {
     nuxtApp.payload.config = {
       public: options.ssrContext.runtimeConfig.public,
       app: options.ssrContext.runtimeConfig.app

packages/nuxt/src/core/runtime/nitro/error.ts

@@ -2,13 +2,14 @@ import { withQuery } from 'ufo'
 import type { NitroErrorHandler } from 'nitropack'
 // @ts-ignore TODO
 import { normalizeError, isJsonRequest } from '#internal/nitro/utils'
+import { NuxtApp } from '#app'
 
 export default <NitroErrorHandler> async function errorhandler (_error, event) {
   // Parse and normalize error
   const { stack, statusCode, statusMessage, message } = normalizeError(_error)
 
   // Create an error object
-  const errorObject = {
+  const errorObject: Exclude<NuxtApp['payload']['error'], Error> = {
     url: event.req.url,
     statusCode,
     statusMessage,
@@ -20,7 +21,7 @@ export default <NitroErrorHandler> async function errorhandler (_error, event) {
   }
 
   // Set response code and message
-  event.res.statusCode = errorObject.statusCode
+  event.res.statusCode = errorObject.statusCode as any as number
   event.res.statusMessage = errorObject.statusMessage
 
   // Console output
@@ -36,7 +37,7 @@ export default <NitroErrorHandler> async function errorhandler (_error, event) {
   }
 
   // HTML response
-  const url = withQuery('/__nuxt_error', errorObject as any)
+  const url = withQuery('/__nuxt_error', errorObject)
   const html = await $fetch(url).catch((error) => {
     console.error('[nitro] Error while generating error response', error)
     return errorObject.statusMessage

packages/nuxt/src/core/runtime/nitro/renderer.ts

@@ -100,7 +100,7 @@ const getSPARenderer = lazyCachedFunction(async () => {
 
 export default eventHandler(async (event) => {
   // Whether we're rendering an error page
-  const ssrError = event.req.url?.startsWith('/__nuxt_error') ? useQuery(event) : null
+  const ssrError = event.req.url?.startsWith('/__nuxt_error') ? useQuery(event) as Exclude<NuxtApp['payload']['error'], Error> : null
   const url = ssrError?.url as string || event.req.url!
 
   // Initialize ssr context
@@ -111,9 +111,9 @@ export default eventHandler(async (event) => {
     res: event.res,
     runtimeConfig: useRuntimeConfig(),
     noSSR: !!event.req.headers['x-nuxt-no-ssr'],
-    error: ssrError,
+    error: !!ssrError,
     nuxt: undefined, /* NuxtApp */
-    payload: undefined
+    payload: ssrError ? { error: ssrError } : undefined
   }
 
   // Render app
@@ -126,8 +126,8 @@ export default eventHandler(async (event) => {
   if (!_rendered) {
     return
   }
-  if (ssrContext.error && !ssrError) {
+  if (ssrContext.payload?.error && !ssrError) {
-    throw ssrContext.error
+    throw ssrContext.payload.error
   }
 
   // Render meta