fix(build): time client, server and nitro from Vite's own bundles

packages/nuxt-cli/src/utils/build-progress.ts

@@ -22,7 +22,6 @@ const HOOK_PHASES: Record<string, string> = {
   'builder:generateApp': 'app',
   'prepare:types': 'types',
   'build:before': 'client',
-  'nitro:build:before': 'nitro',
 }
 
 /** Nitro builds on its own hooks, which Nuxt's never see. */
@@ -45,10 +44,14 @@ interface HookableLike {
 }
 
 interface NuxtLike {
-  options?: { experimental?: { viteEnvironmentApi?: boolean } }
   hooks?: HookableLike
 }
 
+interface VitePluginContext {
+  /** Missing before Vite 6. */
+  environment?: { name: string }
+}
+
 /**
  * Tracks how far a production build has got, so the same transient phase line
  * `nuxt dev` shows can report `nuxt build`, and the completion summary can list
@@ -58,11 +61,10 @@ export class BuildProgress extends PhaseTimeline {
   #message = BUILD_PHASES[0]!.message
   #finished = false
   /**
-   * With the Vite environment API a single build covers both environments, so
-   * the client and server configs resolve up front and cannot mark the boundary
-   * between them.
+   * Vite can resolve every config, and start Nitro's build, before it bundles
+   * anything, so with Vite only its bundle hooks mark the phases.
    */
-  #splitBundles = true
+  #bundledByVite = false
 
   constructor() {
     super(BUILD_PHASES)
@@ -110,16 +112,19 @@ export class BuildProgress extends PhaseTimeline {
    * the project's own build rather than a schedule guessed by the CLI.
    */
   attachNuxt(nuxt: NuxtLike): void {
-    this.#splitBundles = !nuxt.options?.experimental?.viteEnvironmentApi
     nuxt.hooks?.beforeEach?.(({ name, args }) => {
       const phase = HOOK_PHASES[name]
       if (phase) {
-        this.setPhase(phase, phase === 'client' && !this.#splitBundles ? 'Bundling app' : undefined)
+        this.setPhase(phase)
         return
       }
-      if (name === 'vite:configResolved' && this.#splitBundles) {
-        const ctx = args?.[1] as { isServer?: boolean } | undefined
-        this.setPhase(ctx?.isServer ? 'server' : 'client')
+      if (name === 'vite:extend') {
+        this.#bundledByVite = true
+        const { config } = args![0] as { config: { plugins?: unknown[] } }
+        ;(config.plugins ||= []).push(this.#vitePlugin())
+      }
+      else if (name === 'nitro:build:before' && !this.#bundledByVite) {
+        this.setPhase('nitro')
       }
       else if (name === 'webpack:compile') {
         const ctx = args?.[0] as { name?: string } | undefined
@@ -131,6 +136,27 @@ export class BuildProgress extends PhaseTimeline {
     })
   }
 
+  #vitePlugin() {
+    const setPhase = (id: string) => this.setPhase(id)
+    let ssr = false
+    const isServer = (ctx: VitePluginContext) => (ctx.environment?.name ?? (ssr ? 'ssr' : 'client')) === 'ssr'
+    return {
+      name: 'nuxt-cli:build-progress',
+      configResolved(config: { build?: { ssr?: unknown } }) {
+        ssr = !!config.build?.ssr
+      },
+      buildStart(this: VitePluginContext) {
+        setPhase(isServer(this) ? 'server' : 'client')
+      },
+      // Nitro copies public assets and prerenders before its own bundle starts.
+      closeBundle(this: VitePluginContext) {
+        if (isServer(this)) {
+          setPhase('nitro')
+        }
+      },
+    }
+  }
+
   #attachNitro(hooks: HookableLike | undefined): void {
     hooks?.beforeEach?.(({ name, args }) => {
       // Nitro's hooks also run while Nuxt is still bundling the app, and those

packages/nuxt-cli/test/unit/build-progress.spec.ts

@@ -6,19 +6,29 @@ import { BuildProgress } from '../../src/utils/build-progress'
 
 type HookHandler = (event: { name: string, args?: unknown[] }) => void
 
-function nuxtStub(options: { viteEnvironmentApi?: boolean } = {}) {
+interface VitePlugin {
+  configResolved: (config: { build?: { ssr?: unknown } }) => void
+  buildStart: (this: { environment?: { name: string } }) => void
+  closeBundle: (this: { environment?: { name: string } }) => void
+}
+
+function nuxtStub() {
   const handlers: HookHandler[] = []
   const nitroHandlers: HookHandler[] = []
   return {
     nuxt: {
-      options: { experimental: { viteEnvironmentApi: options.viteEnvironmentApi } },
       hooks: { beforeEach: (fn: HookHandler) => void handlers.push(fn) },
     },
     call(name: string, ...args: unknown[]) {
       for (const handler of handlers) {
         handler({ name, args })
       }
     },
+    extendVite() {
+      const config: { plugins?: VitePlugin[] } = {}
+      this.call('vite:extend', { config })
+      return config.plugins![0]!
+    },
     nitro: { hooks: { beforeEach: (fn: HookHandler) => void nitroHandlers.push(fn) } },
     callNitro(name: string, ...args: unknown[]) {
       for (const handler of nitroHandlers) {
@@ -45,8 +55,13 @@ describe('build progress', () => {
     stub.call('builder:generateApp')
     stub.call('prepare:types')
     stub.call('build:before')
-    stub.call('vite:configResolved', {}, { isClient: true, isServer: false })
-    stub.call('vite:configResolved', {}, { isClient: false, isServer: true })
+    const plugin = stub.extendVite()
+    plugin.configResolved({ build: {} })
+    plugin.buildStart.call({})
+    plugin.closeBundle.call({})
+    plugin.configResolved({ build: { ssr: true } })
+    plugin.buildStart.call({})
+    plugin.closeBundle.call({})
     stub.call('nitro:build:before', {})
     progress.finish()
 
@@ -62,17 +77,27 @@ describe('build progress', () => {
     expect(progress.timings.map(timing => timing.phase)).toEqual(['config', 'modules', 'app', 'types', 'client', 'server', 'nitro'])
   })
 
-  it('should not split the bundle phase when a single build covers both environments', () => {
+  it('should time each bundle when Vite builds every environment in one run', () => {
     const progress = new BuildProgress()
-    const stub = nuxtStub({ viteEnvironmentApi: true })
+    const stub = nuxtStub()
     progress.attachNuxt(stub.nuxt)
     const seen = messages(progress)
 
     stub.call('build:before')
+    const plugin = stub.extendVite()
     stub.call('vite:configResolved', {}, { isClient: true, isServer: false })
     stub.call('vite:configResolved', {}, { isClient: false, isServer: true })
+    stub.call('nitro:build:before', {})
+    expect(seen).toEqual(['Loading Nuxt config', 'Bundling client'])
+
+    for (const name of ['client', 'ssr', 'nitro']) {
+      plugin.buildStart.call({ environment: { name } })
+      plugin.closeBundle.call({ environment: { name } })
+    }
+    progress.finish()
 
-    expect(seen).toEqual(['Loading Nuxt config', 'Bundling app'])
+    expect(seen).toEqual(['Loading Nuxt config', 'Bundling client', 'Bundling server', 'Building Nitro server'])
+    expect(progress.timings.map(timing => timing.phase)).toEqual(['config', 'client', 'server', 'nitro'])
   })
 
   it('should name what the Nitro phase is doing', () => {