wip: devtools integration

packages/next/src/client/components/react-dev-overlay/app/hot-reloader-client.tsx

@@ -4,6 +4,7 @@ import stripAnsi from 'next/dist/compiled/strip-ansi'
 import formatWebpackMessages from '../internal/helpers/format-webpack-messages'
 import { useRouter } from '../../navigation'
 import {
+  ACTION_AFTER_ERROR,
   ACTION_BEFORE_REFRESH,
   ACTION_BUILD_ERROR,
   ACTION_BUILD_OK,
@@ -38,10 +39,12 @@ import type { HydrationErrorState } from '../internal/helpers/hydration-error-in
 import type { DebugInfo } from '../types'
 import { useUntrackedPathname } from '../../navigation-untracked'
 import { getReactStitchedError } from '../internal/helpers/stitched-error'
+import { decorateServerError } from '../../../../shared/lib/error-source'
 
 export interface Dispatcher {
   onBuildOk(): void
   onBuildError(message: string): void
+  onAfterError(error: Error): void
   onVersionInfo(versionInfo: VersionInfo): void
   onDebugInfo(debugInfo: DebugInfo): void
   onBeforeRefresh(): void
@@ -276,7 +279,19 @@ function processMessage(
     return
   }
 
-  function handleErrors(errors: ReadonlyArray<unknown>) {
+  function handleAfterErrors(errors: ReadonlyArray<Error>) {
+    console.log('handleAfterErrors', errors)
+    for (const error of errors) {
+      dispatcher.onAfterError(error)
+    }
+
+    // // Also log them to the console.
+    // for (let i = 0; i < errors.length; i++) {
+    //   console.error(errors[i])
+    // }
+  }
+
+  function handleBuildErrors(errors: ReadonlyArray<unknown>) {
     // "Massage" webpack messages.
     const formatted = formatWebpackMessages({
       errors: errors,
@@ -387,7 +402,7 @@ function processMessage(
           })
         )
 
-        handleErrors(errors)
+        handleBuildErrors(errors)
         return
       }
 
@@ -501,13 +516,24 @@ function processMessage(
       // TODO-APP: potentially only refresh if the currently viewed page was added/removed.
       return router.hmrRefresh()
     }
+    case HMR_ACTIONS_SENT_TO_BROWSER.AFTER_ERROR: {
+      const { errorJSON, source } = obj
+      if (errorJSON) {
+        const { message, stack } = JSON.parse(errorJSON)
+        const error = new Error(message)
+        error.stack = stack
+        decorateServerError(error, source ?? 'server')
+        handleAfterErrors([error])
+      }
+      return
+    }
     case HMR_ACTIONS_SENT_TO_BROWSER.SERVER_ERROR: {
       const { errorJSON } = obj
       if (errorJSON) {
         const { message, stack } = JSON.parse(errorJSON)
         const error = new Error(message)
         error.stack = stack
-        handleErrors([error])
+        handleBuildErrors([error])
       }
       return
     }
@@ -536,6 +562,13 @@ export default function HotReload({
       onBuildError(message) {
         dispatch({ type: ACTION_BUILD_ERROR, message })
       },
+      onAfterError(reason) {
+        dispatch({
+          type: ACTION_AFTER_ERROR,
+          reason,
+          frames: parseStack(reason.stack!),
+        })
+      },
       onBeforeRefresh() {
         dispatch({ type: ACTION_BEFORE_REFRESH })
       },

packages/next/src/client/components/react-dev-overlay/internal/container/Errors.tsx

@@ -1,7 +1,9 @@
 import { useState, useEffect, useMemo, useCallback } from 'react'
 import {
+  ACTION_AFTER_ERROR,
   ACTION_UNHANDLED_ERROR,
   ACTION_UNHANDLED_REJECTION,
+  type AfterErrorAction,
   type UnhandledErrorAction,
   type UnhandledRejectionAction,
 } from '../../shared'
@@ -38,7 +40,7 @@ import {
 
 export type SupportedErrorEvent = {
   id: number
-  event: UnhandledErrorAction | UnhandledRejectionAction
+  event: UnhandledErrorAction | UnhandledRejectionAction | AfterErrorAction
 }
 export type ErrorsProps = {
   isAppDir: boolean
@@ -98,6 +100,7 @@ function ErrorDescription({
 function getErrorSignature(ev: SupportedErrorEvent): string {
   const { event } = ev
   switch (event.type) {
+    case ACTION_AFTER_ERROR:
     case ACTION_UNHANDLED_ERROR:
     case ACTION_UNHANDLED_REJECTION: {
       return `${event.reason.name}::${event.reason.message}::${event.reason.stack}`

packages/next/src/client/components/react-dev-overlay/internal/helpers/get-error-by-type.ts

@@ -1,4 +1,5 @@
 import {
+  ACTION_AFTER_ERROR,
   ACTION_UNHANDLED_ERROR,
   ACTION_UNHANDLED_REJECTION,
 } from '../../shared'
@@ -22,6 +23,7 @@ export async function getErrorByType(
 ): Promise<ReadyRuntimeError> {
   const { id, event } = ev
   switch (event.type) {
+    case ACTION_AFTER_ERROR:
     case ACTION_UNHANDLED_ERROR:
     case ACTION_UNHANDLED_REJECTION: {
       const readyRuntimeError: ReadyRuntimeError = {

packages/next/src/client/components/react-dev-overlay/shared.ts

@@ -32,6 +32,7 @@ export const ACTION_REFRESH = 'fast-refresh'
 export const ACTION_VERSION_INFO = 'version-info'
 export const ACTION_UNHANDLED_ERROR = 'unhandled-error'
 export const ACTION_UNHANDLED_REJECTION = 'unhandled-rejection'
+export const ACTION_AFTER_ERROR = 'after-error'
 export const ACTION_DEBUG_INFO = 'debug-info'
 
 interface StaticIndicatorAction {
@@ -66,6 +67,12 @@ export interface UnhandledRejectionAction {
   frames: StackFrame[]
 }
 
+export interface AfterErrorAction {
+  type: typeof ACTION_AFTER_ERROR
+  reason: Error
+  frames: StackFrame[]
+}
+
 export interface DebugInfoAction {
   type: typeof ACTION_DEBUG_INFO
   debugInfo: any
@@ -83,6 +90,7 @@ export type BusEvent =
   | FastRefreshAction
   | UnhandledErrorAction
   | UnhandledRejectionAction
+  | AfterErrorAction
   | VersionInfoAction
   | StaticIndicatorAction
   | DebugInfoAction
@@ -147,8 +155,10 @@ export function useErrorOverlayReducer() {
           refreshState: { type: 'idle' },
         }
       }
+      case ACTION_AFTER_ERROR:
       case ACTION_UNHANDLED_ERROR:
       case ACTION_UNHANDLED_REJECTION: {
+        console.log('useErrorOverlayReducer', action)
         switch (_state.refreshState.type) {
           case 'idle': {
             return {

packages/next/src/server/base-server.ts

@@ -366,6 +366,8 @@ export default abstract class Server<
   protected readonly enabledDirectories: NextEnabledDirectories
   protected abstract getEnabledDirectories(dev: boolean): NextEnabledDirectories
 
+  protected afterTaskErrorHandler: ((error: unknown) => void) | undefined
+
   protected readonly experimentalTestProxy?: boolean
 
   protected abstract findPageComponents(params: {
@@ -2437,7 +2439,7 @@ export default abstract class Server<
         postponed,
         waitUntil: this.getWaitUntil(),
         onClose: res.onClose.bind(res),
-        onAfterTaskError: undefined,
+        onAfterTaskError: this.afterTaskErrorHandler,
         // only available in dev
         setAppIsrStatus: (this as any).setAppIsrStatus,
       }
@@ -2484,7 +2486,7 @@ export default abstract class Server<
               isRevalidate: isSSG,
               waitUntil: this.getWaitUntil(),
               onClose: res.onClose.bind(res),
-              onAfterTaskError: undefined,
+              onAfterTaskError: this.afterTaskErrorHandler,
               onInstrumentationRequestError:
                 this.renderOpts.onInstrumentationRequestError,
               buildId: this.renderOpts.buildId,

packages/next/src/server/dev/hot-reloader-types.ts

@@ -7,6 +7,7 @@ import type { RouteDefinition } from '../route-definitions/route-definition'
 import type { Project, Update as TurbopackUpdate } from '../../build/swc/types'
 import type { VersionInfo } from './parse-version-info'
 import type { DebugInfo } from '../../client/components/react-dev-overlay/types'
+import type { ErrorSourceType } from '../../shared/lib/error-source'
 
 export const enum HMR_ACTIONS_SENT_TO_BROWSER {
   ADDED_PAGE = 'addedPage',
@@ -22,6 +23,7 @@ export const enum HMR_ACTIONS_SENT_TO_BROWSER {
   DEV_PAGES_MANIFEST_UPDATE = 'devPagesManifestUpdate',
   TURBOPACK_MESSAGE = 'turbopack-message',
   SERVER_ERROR = 'serverError',
+  AFTER_ERROR = 'afterError',
   TURBOPACK_CONNECTED = 'turbopack-connected',
   APP_ISR_MANIFEST = 'appIsrManifest',
 }
@@ -31,6 +33,12 @@ interface ServerErrorAction {
   errorJSON: string
 }
 
+export interface AfterErrorAction {
+  action: HMR_ACTIONS_SENT_TO_BROWSER.AFTER_ERROR
+  source: ErrorSourceType
+  errorJSON: string
+}
+
 export interface TurbopackMessageAction {
   action: HMR_ACTIONS_SENT_TO_BROWSER.TURBOPACK_MESSAGE
   data: TurbopackUpdate | TurbopackUpdate[]
@@ -130,6 +138,7 @@ export type HMR_ACTION_TYPES =
   | ServerOnlyChangesAction
   | DevPagesManifestUpdateAction
   | ServerErrorAction
+  | AfterErrorAction
   | AppIsrManifestAction
 
 export type TurbopackMsgToBrowser =

packages/next/src/server/dev/next-dev-server.ts

@@ -200,6 +200,15 @@ export default class DevServer extends Server {
     this.pagesDir = pagesDir
     this.appDir = appDir
 
+    if (this.nextConfig.experimental.after) {
+      this.afterTaskErrorHandler = (error: unknown) => {
+        return this.bundlerService.reportAfterTaskError(
+          error,
+          process.env.NEXT_RUNTIME === 'edge' ? 'edge-server' : 'server'
+        )
+      }
+    }
+
     if (this.nextConfig.experimental.serverComponentsHmrCache) {
       this.serverComponentsHmrCache = new LRUCache(
         this.nextConfig.cacheMaxMemorySize,

packages/next/src/server/lib/dev-bundler-service.ts

@@ -36,6 +36,11 @@ export class DevBundlerService {
   public logErrorWithOriginalStack =
     this.bundler.logErrorWithOriginalStack.bind(this.bundler)
 
+  public reportAfterTaskError: typeof this.bundler.reportAfterTaskError =
+    async (...args) => {
+      return await this.bundler.reportAfterTaskError(...args)
+    }
+
   public async getFallbackErrorComponents(url?: string) {
     await this.bundler.hotReloader.buildFallbackError()
     // Build the error page to ensure the fallback is built too.

packages/next/src/server/lib/router-utils/setup-dev-bundler.ts

@@ -75,6 +75,9 @@ import { normalizeMetadataPageToRoute } from '../../../lib/metadata/get-metadata
 import { createEnvDefinitions } from '../experimental/create-env-definitions'
 import { JsConfigPathsPlugin } from '../../../build/webpack/plugins/jsconfig-paths-plugin'
 import { store as consoleStore } from '../../../build/output/store'
+import { type ErrorSourceType } from '../../../shared/lib/error-source'
+import { stringifyError } from '../../../shared/lib/utils'
+import isError from '../../../lib/is-error'
 
 export type SetupOpts = {
   renderServer: LazyRenderServerInstance
@@ -950,11 +953,32 @@ async function startWatcher(opts: SetupOpts) {
     }
   }
 
+  async function reportAfterTaskError(error: unknown, source: ErrorSourceType) {
+    const serializeErrorToJSON = (err: unknown) => {
+      if (isError(err)) {
+        return stringifyError(err)
+      }
+
+      try {
+        return JSON.stringify(err)
+      } catch (_) {
+        return '<unknown>'
+      }
+    }
+
+    hotReloader.send({
+      action: HMR_ACTIONS_SENT_TO_BROWSER.AFTER_ERROR,
+      source: source,
+      errorJSON: serializeErrorToJSON(error),
+    })
+  }
+
   return {
     serverFields,
     hotReloader,
     requestHandler,
     logErrorWithOriginalStack,
+    reportAfterTaskError,
 
     async ensureMiddleware(requestUrl?: string) {
       if (!serverFields.actualMiddlewareFile) return

test/e2e/app-dir/next-after-app/app/test/layout.js

@@ -0,0 +1,12 @@
+export const metadata = {
+  title: 'Next.js',
+  description: 'Generated by Next.js',
+}
+
+export default function RootLayout({ children }) {
+  return (
+    <html lang="en">
+      <body>{children}</body>
+    </html>
+  )
+}

test/e2e/app-dir/next-after-app/app/test/nested/page.js

@@ -0,0 +1,25 @@
+import { unstable_after } from 'next/server'
+import { setTimeout } from 'timers/promises'
+
+export default function Page() {
+  helper()
+  return null
+}
+
+function helper() {
+  unstable_after(async () => {
+    await setTimeout(500)
+    nestedHelper()
+  })
+}
+
+function nestedHelper() {
+  unstable_after(async () => {
+    await setTimeout(500)
+    throws()
+  })
+}
+
+function throws() {
+  throw new Error('kaboom')
+}

test/e2e/app-dir/next-after-app/app/test/page.js

@@ -0,0 +1,21 @@
+import { unstable_after } from 'next/server'
+import { setTimeout } from 'timers/promises'
+
+export default function Page() {
+  helper()
+  return null
+}
+
+function helper() {
+  unstable_after(async () => {
+    // TODO(after): this delay is load-bearing, otherwise
+    // the client-side won't have booted yet and our `HMR_ACTIONS_SENT_TO_BROWSER.AFTER_ERROR`
+    // will be dropped on the floor, so we won't display anything
+    await setTimeout(1000)
+    throws()
+  })
+}
+
+function throws() {
+  throw new Error('kaboom')
+}