Record leveraged configs

packages/next/build/index.ts

@@ -1048,6 +1048,9 @@ export default async function build(
         (staticPages.size + ssgPages.size + serverPropsPages.size),
       hasStatic404: useStatic404,
       hasReportWebVitals: namedExports?.includes('reportWebVitals') ?? false,
+      rewritesCount: rewrites.length,
+      headersCount: headers.length,
+      redirectsCount: redirects.length - 1, // reduce one for trailing slash
     })
   )
 

packages/next/telemetry/events/build.ts

@@ -45,6 +45,9 @@ type EventBuildOptimized = {
   hasTestPages: boolean
   hasStatic404: boolean
   hasReportWebVitals: boolean
+  headersCount: number
+  rewritesCount: number
+  redirectsCount: number
 }
 
 export function eventBuildOptimize(

packages/next/telemetry/events/version.ts

@@ -21,6 +21,17 @@ type EventCliSessionStarted = {
   buildTarget: string
   hasWebpackConfig: boolean
   hasBabelConfig: boolean
+  basePathEnabled: boolean
+  i18nEnabled: boolean
+  imageEnabled: boolean
+  locales: string | null
+  localeDomainsCount: number | null
+  localeDetectionEnabled: boolean | null
+  imageDomainsCount: number | null
+  imageSizes: string | null
+  imageLoader: string | null
+  trailingSlashEnabled: boolean
+  reactStrictMode: boolean
 }
 
 function hasBabelConfig(dir: string): boolean {
@@ -83,6 +94,17 @@ export function eventCliSession(
     | 'buildTarget'
     | 'hasWebpackConfig'
     | 'hasBabelConfig'
+    | 'basePathEnabled'
+    | 'i18nEnabled'
+    | 'imageEnabled'
+    | 'locales'
+    | 'localeDomainsCount'
+    | 'localeDetectionEnabled'
+    | 'imageDomainsCount'
+    | 'imageSizes'
+    | 'imageLoader'
+    | 'trailingSlashEnabled'
+    | 'reactStrictMode'
   >
 ): { eventName: string; payload: EventCliSessionStarted }[] {
   // This should be an invariant, if it fails our build tooling is broken.
@@ -92,6 +114,9 @@ export function eventCliSession(
 
   const userConfiguration = getNextConfig(phase, dir)
 
+  const { images, experimental } = userConfiguration || {}
+  const { i18n } = experimental || {}
+
   const payload: EventCliSessionStarted = {
     nextVersion: process.env.__NEXT_VERSION,
     nodeVersion: process.version,
@@ -103,6 +128,17 @@ export function eventCliSession(
     buildTarget: userConfiguration?.target ?? 'default',
     hasWebpackConfig: typeof userConfiguration?.webpack === 'function',
     hasBabelConfig: hasBabelConfig(dir),
+    imageEnabled: !!images,
+    basePathEnabled: !!userConfiguration?.basePath,
+    i18nEnabled: !!i18n,
+    locales: i18n?.locales ? i18n.locales.join(',') : null,
+    localeDomainsCount: i18n?.domains ? i18n.domains.length : null,
+    localeDetectionEnabled: !i18n ? null : i18n.localeDetection !== false,
+    imageDomainsCount: images?.domains ? images.domains.length : null,
+    imageSizes: images?.sizes ? images.sizes.join(',') : null,
+    imageLoader: images?.loader,
+    trailingSlashEnabled: !!userConfiguration?.trailingSlash,
+    reactStrictMode: !!userConfiguration?.reactStrictMode,
   }
   return [{ eventName: EVENT_VERSION, payload }]
 }

test/integration/telemetry/next.config.custom-routes

@@ -0,0 +1,38 @@
+module.exports = phase => {
+  return {
+    rewrites() {
+      return [
+        {
+          source: '/hello-1',
+          destination: '/world'
+        },
+        {
+          source: '/hello-2',
+          destination: '/world'
+        },
+      ]
+    },
+    redirects() {
+      return [
+        {
+          source: '/hello-3',
+          destination: '/world',
+          permanent: false
+        }
+      ]
+    },
+    headers() {
+      return [
+        {
+          source: '/hello-4',
+          headers: [
+            {
+              key: 'x-path',
+              value: 'hello-4'
+            }
+          ]
+        }
+      ]
+    }
+  }
+}

test/integration/telemetry/next.config.i18n-images

@@ -0,0 +1,24 @@
+module.exports = phase => {
+  return {
+    images: {
+      sizes: [64, 128, 256, 512, 1024],
+      domains: ['example.com'],
+    },
+    experimental: {
+      i18n: {
+        locales: ['en','nl','fr'],
+        defaultLocale: 'en',
+        domains: [
+          {
+            domain: 'example.com',
+            defaultLocale: 'en'
+          },
+          {
+            domain: 'example.fr',
+            defaultLocale: 'fr'
+          }
+        ]
+      }
+    }
+  }
+}

test/integration/telemetry/test/index.test.js

@@ -420,4 +420,91 @@ describe('Telemetry CLI', () => {
     event1 = /NEXT_BUILD_OPTIMIZED[\s\S]+?{([\s\S]+?)}/.exec(build.stderr).pop()
     expect(event1).toMatch(/hasReportWebVitals.*?false/)
   })
+
+  it('detects rewrites, headers, and redirects for next build', async () => {
+    await fs.rename(
+      path.join(appDir, 'next.config.custom-routes'),
+      path.join(appDir, 'next.config.js')
+    )
+
+    const { stderr } = await nextBuild(appDir, [], {
+      stderr: true,
+      env: { NEXT_TELEMETRY_DEBUG: 1 },
+    })
+
+    await fs.rename(
+      path.join(appDir, 'next.config.js'),
+      path.join(appDir, 'next.config.custom-routes')
+    )
+
+    const event1 = /NEXT_BUILD_OPTIMIZED[\s\S]+?{([\s\S]+?)}/.exec(stderr).pop()
+    expect(event1).toMatch(/"headersCount": 1/)
+    expect(event1).toMatch(/"rewritesCount": 2/)
+    expect(event1).toMatch(/"redirectsCount": 1/)
+  })
+
+  it('detects i18n and image configs for session start', async () => {
+    await fs.rename(
+      path.join(appDir, 'next.config.i18n-images'),
+      path.join(appDir, 'next.config.js')
+    )
+
+    const { stderr } = await nextBuild(appDir, [], {
+      stderr: true,
+      env: { NEXT_TELEMETRY_DEBUG: 1 },
+    })
+
+    await fs.rename(
+      path.join(appDir, 'next.config.js'),
+      path.join(appDir, 'next.config.i18n-images')
+    )
+
+    const event1 = /NEXT_CLI_SESSION_STARTED[\s\S]+?{([\s\S]+?)}/
+      .exec(stderr)
+      .pop()
+
+    expect(event1).toMatch(/"i18nEnabled": true/)
+    expect(event1).toMatch(/"locales": "en,nl,fr"/)
+    expect(event1).toMatch(/"localeDomainsCount": 2/)
+    expect(event1).toMatch(/"localeDetectionEnabled": true/)
+    expect(event1).toMatch(/"imageDomainsCount": 1/)
+    expect(event1).toMatch(/"imageSizes": "64,128,256,512,1024"/)
+    expect(event1).toMatch(/"trailingSlashEnabled": false/)
+    expect(event1).toMatch(/"reactStrictMode": false/)
+
+    await fs.rename(
+      path.join(appDir, 'next.config.i18n-images'),
+      path.join(appDir, 'next.config.js')
+    )
+
+    let stderr2 = ''
+
+    let app = await launchApp(appDir, await findPort(), {
+      onStderr(msg) {
+        stderr2 += msg || ''
+      },
+      env: {
+        NEXT_TELEMETRY_DEBUG: 1,
+      },
+    })
+    await waitFor(1000)
+    await killApp(app)
+
+    await fs.rename(
+      path.join(appDir, 'next.config.js'),
+      path.join(appDir, 'next.config.i18n-images')
+    )
+
+    const event2 = /NEXT_CLI_SESSION_STARTED[\s\S]+?{([\s\S]+?)}/
+      .exec(stderr2)
+      .pop()
+    expect(event2).toMatch(/"i18nEnabled": true/)
+    expect(event2).toMatch(/"locales": "en,nl,fr"/)
+    expect(event2).toMatch(/"localeDomainsCount": 2/)
+    expect(event2).toMatch(/"localeDetectionEnabled": true/)
+    expect(event2).toMatch(/"imageDomainsCount": 1/)
+    expect(event2).toMatch(/"imageSizes": "64,128,256,512,1024"/)
+    expect(event2).toMatch(/"trailingSlashEnabled": false/)
+    expect(event2).toMatch(/"reactStrictMode": false/)
+  })
 })