[next] Re-enable shared lambdas by default (#4757)

This re-enables the shared lambdas optimization by default and also adds additional tests to ensure that when a `now.json` or `vercel.json` contains either `routes` or `functions` configs the shared lambda optimization is disabled. 

Additional test deployments done:

- minimal `now.json` with `builds` config [deploy](https://shared-lambdas-tests-d646fsqju.vercel.app)
- `now.json` with `functions` config [deploy](https://shared-lambdas-tests-ahnuosp4s.vercel.app)
- `now.json` with `routes` config [deploy](https://shared-lambdas-tests-gulam3jda.vercel.app)
- minimal `vercel.json` with `builds` config [deploy](https://shared-lambdas-tests-7ic7wzirs.vercel.app)
- `vercel.json` with `functions` config [deploy](https://shared-lambdas-tests-7ic7wzirs.vercel.app)
- `vercel.json` with `routes` config [deploy](https://shared-lambdas-tests-rja2391tq.vercel.app)

packages/now-next/src/index.ts

@@ -71,7 +71,7 @@ import {
   syncEnvVars,
   validateEntrypoint,
 } from './utils';
-// import findUp from 'find-up';
+import findUp from 'find-up';
 import { Sema } from 'async-sema';
 
 interface BuildParamsMeta {
@@ -231,47 +231,39 @@ export const build = async ({
     });
   }
 
-  // let nowJsonPath = Object.keys(files).find(file => {
+  const nowJsonPath = await findUp(['now.json', 'vercel.json'], {
-  //   return file.endsWith('now.json') || file.endsWith('vercel.json')
+    cwd: path.join(workPath, path.dirname(entrypoint)),
-  // })
+  });
 
-  // if (nowJsonPath) nowJsonPath = files[nowJsonPath].fsPath
+  let hasLegacyRoutes = false;
+  const hasFunctionsConfig = !!config.functions;
 
-  // if (!nowJsonPath) {
+  if (nowJsonPath) {
-  //   nowJsonPath = await findUp(['now.json', 'vercel.json'], {
+    const nowJsonData = JSON.parse(await readFile(nowJsonPath, 'utf8'));
-  //     cwd: path.join(workPath, path.dirname(entrypoint))
-  //   })
-  // }
 
-  // let hasLegacyRoutes = false;
+    if (Array.isArray(nowJsonData.routes) && nowJsonData.routes.length > 0) {
-  // const hasFunctionsConfig = !!config.functions;
+      hasLegacyRoutes = true;
+      console.warn(
+        `WARNING: your application is being opted out of @vercel/next's optimized lambdas mode due to legacy routes in ${path.basename(
+          nowJsonPath
+        )}. http://err.sh/vercel/vercel/next-legacy-routes-optimized-lambdas`
+      );
+    }
+  }
 
-  // if (nowJsonPath) {
+  if (hasFunctionsConfig) {
-  //   const nowJsonData = JSON.parse(await readFile(nowJsonPath, 'utf8'));
+    console.warn(
-
+      `WARNING: Your application is being opted out of "@vercel/next" optimized lambdas mode due to \`functions\` config.\nMore info: http://err.sh/vercel/vercel/next-functions-config-optimized-lambdas`
-  //   if (Array.isArray(nowJsonData.routes) && nowJsonData.routes.length > 0) {
+    );
-  //     hasLegacyRoutes = true;
+  }
-  //     console.warn(
-  //       `WARNING: your application is being opted out of @vercel/next's optimized lambdas mode due to legacy routes in ${path.basename(
-  //         nowJsonPath
-  //       )}. http://err.sh/vercel/vercel/next-legacy-routes-optimized-lambdas`
-  //     );
-  //   }
-  // }
-
-  // if (hasFunctionsConfig) {
-  //   console.warn(
-  //     `WARNING: Your application is being opted out of "@vercel/next" optimized lambdas mode due to \`functions\` config.\nMore info: http://err.sh/vercel/vercel/next-functions-config-optimized-lambdas`
-  //   );
-  // }
 
   // default to true but still allow opting out with the config
-  const isSharedLambdas = !!config.sharedLambdas;
+  const isSharedLambdas =
-  // !hasLegacyRoutes &&
+    !hasLegacyRoutes &&
-  // !hasFunctionsConfig &&
+    !hasFunctionsConfig &&
-  // typeof config.sharedLambdas === 'undefined'
+    typeof config.sharedLambdas === 'undefined'
-  //   ? true
+      ? true
-  //   : !!config.sharedLambdas;
+      : !!config.sharedLambdas;
 
   if (meta.isDev) {
     let childProcess: ChildProcess | undefined;

packages/now-next/test/fixtures/00-shared-lambdas/now.json

@@ -1,12 +1,10 @@
 {
   "version": 2,
+  "uploadNowJson": true,
   "builds": [
     {
       "src": "package.json",
-      "use": "@vercel/next",
+      "use": "@vercel/next"
-      "config": {
-        "sharedLambdas": true
-      }
     }
   ],
   "probes": [
@@ -29,6 +27,12 @@
     {
       "path": "/another/invite/hello",
       "mustContain": "hello from /[teamSlug]/[project]/[id]"
+    },
+    {
+      "logMustNotContain": "WARNING: your application is being opted out of @vercel/next's optimized lambdas mode due to legacy routes"
+    },
+    {
+      "logMustNotContain": "WARNING: Your application is being opted out of \"@vercel/next\" optimized lambdas mode due to `functions` config"
     }
   ]
 }

packages/now-next/test/fixtures/06-lambda-with-memory/now.json

@@ -17,6 +17,9 @@
       "path": "/api/memory",
       "status": 200,
       "mustContain": "128"
+    },
+    {
+      "logMustContain": "WARNING: Your application is being opted out of \"@vercel/next\" optimized lambdas mode due to `functions` config"
     }
   ]
 }

packages/now-next/test/fixtures/07-custom-routes/now.json

@@ -1,5 +1,6 @@
 {
   "version": 2,
+  "uploadNowJson": true,
   "builds": [{ "src": "package.json", "use": "@vercel/next" }],
   "probes": [
     {
@@ -61,6 +62,12 @@
         "x-hello": "world",
         "x-another": "value"
       }
+    },
+    {
+      "logMustNotContain": "WARNING: your application is being opted out of @vercel/next's optimized lambdas mode due to legacy routes"
+    },
+    {
+      "logMustNotContain": "WARNING: Your application is being opted out of \"@vercel/next\" optimized lambdas mode due to `functions` config"
     }
   ]
 }

packages/now-next/test/fixtures/09-yarn-workspaces/now.json

@@ -1,11 +1,15 @@
 {
   "version": 2,
+  "uploadNowJson": true,
   "builds": [{ "src": "packages/web/next.config.js", "use": "@vercel/next" }],
   "routes": [{ "src": "/(.*)", "dest": "/packages/web/$1", "continue": true }],
   "probes": [
     {
       "path": "/",
       "mustContain": "hello world <!-- -->6"
+    },
+    {
+      "logMustContain": "WARNING: your application is being opted out of @vercel/next's optimized lambdas mode due to legacy routes"
     }
   ]
 }

packages/now-next/test/fixtures/22-ssg-v2-shared-lambdas/additional.js

@@ -1,159 +0,0 @@
-/* eslint-env jest */
-const fetch = require('node-fetch');
-const cheerio = require('cheerio');
-
-module.exports = function(ctx) {
-  it('should revalidate content properly from pathname', async () => {
-    const res = await fetch(`${ctx.deploymentUrl}/another`);
-    expect(res.status).toBe(200);
-
-    let $ = cheerio.load(await res.text());
-    const initialTime = $('#time').text();
-    const initialRandom = $('#random').text();
-    expect($('#hello').text()).toBe('hello: world');
-
-    // wait for revalidation to occur
-    await new Promise(resolve => setTimeout(resolve, 2000));
-
-    const res2 = await fetch(`${ctx.deploymentUrl}/another`);
-    expect(res2.status).toBe(200);
-
-    $ = cheerio.load(await res2.text());
-    expect($('#hello').text()).toBe('hello: world');
-    expect(initialTime).not.toBe($('#time').text());
-    expect(initialRandom).not.toBe($('#random').text());
-  });
-
-  it('should revalidate content properly from dynamic pathname', async () => {
-    const res = await fetch(`${ctx.deploymentUrl}/blog/post-123`);
-    expect(res.status).toBe(200);
-
-    let $ = cheerio.load(await res.text());
-    const initialTime = $('#time').text();
-    const initialRandom = $('#random').text();
-    expect($('#post').text()).toBe('Post: post-123');
-
-    // wait for revalidation to occur
-    await new Promise(resolve => setTimeout(resolve, 2000));
-
-    const res2 = await fetch(`${ctx.deploymentUrl}/blog/post-123`);
-    expect(res2.status).toBe(200);
-
-    $ = cheerio.load(await res2.text());
-    expect($('#post').text()).toBe('Post: post-123');
-    expect(initialTime).not.toBe($('#time').text());
-    expect(initialRandom).not.toBe($('#random').text());
-  });
-
-  it('should revalidate content properly from dynamic pathnames', async () => {
-    const res = await fetch(`${ctx.deploymentUrl}/blog/post-123/comment-321`);
-    expect(res.status).toBe(200);
-
-    let $ = cheerio.load(await res.text());
-    const initialTime = $('#time').text();
-    const initialRandom = $('#random').text();
-    expect($('#post').text()).toBe('Post: post-123');
-    expect($('#comment').text()).toBe('Comment: comment-321');
-
-    // wait for revalidation to occur
-    await new Promise(resolve => setTimeout(resolve, 2000));
-
-    const res2 = await fetch(`${ctx.deploymentUrl}/blog/post-123/comment-321`);
-    expect(res2.status).toBe(200);
-
-    $ = cheerio.load(await res2.text());
-    expect($('#post').text()).toBe('Post: post-123');
-    expect($('#comment').text()).toBe('Comment: comment-321');
-    expect(initialTime).not.toBe($('#time').text());
-    expect(initialRandom).not.toBe($('#random').text());
-  });
-
-  it('should revalidate content properly from /_next/data pathname', async () => {
-    const res = await fetch(
-      `${ctx.deploymentUrl}/_next/data/testing-build-id/another.json`
-    );
-    expect(res.status).toBe(200);
-
-    const { pageProps: data } = await res.json();
-    const initialTime = data.time;
-    const initialRandom = data.random;
-    expect(data.world).toBe('world');
-    expect(isNaN(initialTime)).toBe(false);
-    expect(isNaN(initialRandom)).toBe(false);
-
-    // wait for revalidation to occur
-    await new Promise(resolve => setTimeout(resolve, 2000));
-
-    const res2 = await fetch(
-      `${ctx.deploymentUrl}/_next/data/testing-build-id/another.json`
-    );
-    expect(res2.status).toBe(200);
-
-    const { pageProps: data2 } = await res2.json();
-    expect(data2.world).toBe('world');
-    expect(isNaN(data2.time)).toBe(false);
-    expect(isNaN(data2.random)).toBe(false);
-    expect(initialTime).not.toBe(data2.time);
-    expect(initialRandom).not.toBe(data2.random);
-  });
-
-  it('should revalidate content properly from /_next/data dynamic pathname', async () => {
-    const res = await fetch(
-      `${ctx.deploymentUrl}/_next/data/testing-build-id/blog/post-123.json`
-    );
-    expect(res.status).toBe(200);
-
-    const { pageProps: data } = await res.json();
-    const initialTime = data.time;
-    const initialRandom = data.random;
-    expect(data.post).toBe('post-123');
-    expect(isNaN(initialTime)).toBe(false);
-    expect(isNaN(initialRandom)).toBe(false);
-
-    // wait for revalidation to occur
-    await new Promise(resolve => setTimeout(resolve, 2000));
-
-    const res2 = await fetch(
-      `${ctx.deploymentUrl}/_next/data/testing-build-id/blog/post-123.json`
-    );
-    expect(res2.status).toBe(200);
-
-    const { pageProps: data2 } = await res2.json();
-    expect(data2.post).toBe('post-123');
-    expect(isNaN(data2.time)).toBe(false);
-    expect(isNaN(data2.random)).toBe(false);
-    expect(initialTime).not.toBe(data2.time);
-    expect(initialRandom).not.toBe(data2.random);
-  });
-
-  it('should revalidate content properly from /_next/data dynamic pathnames', async () => {
-    const res = await fetch(
-      `${ctx.deploymentUrl}/_next/data/testing-build-id/blog/post-123/comment-321.json`
-    );
-    expect(res.status).toBe(200);
-
-    const { pageProps: data } = await res.json();
-    const initialTime = data.time;
-    const initialRandom = data.random;
-    expect(data.post).toBe('post-123');
-    expect(data.comment).toBe('comment-321');
-    expect(isNaN(initialTime)).toBe(false);
-    expect(isNaN(initialRandom)).toBe(false);
-
-    // wait for revalidation to occur
-    await new Promise(resolve => setTimeout(resolve, 2000));
-
-    const res2 = await fetch(
-      `${ctx.deploymentUrl}/_next/data/testing-build-id/blog/post-123/comment-321.json`
-    );
-    expect(res2.status).toBe(200);
-
-    const { pageProps: data2 } = await res2.json();
-    expect(data2.post).toBe('post-123');
-    expect(data2.comment).toBe('comment-321');
-    expect(isNaN(data2.time)).toBe(false);
-    expect(isNaN(data2.random)).toBe(false);
-    expect(initialTime).not.toBe(data2.time);
-    expect(initialRandom).not.toBe(data2.random);
-  });
-};

packages/now-next/test/fixtures/22-ssg-v2-shared-lambdas/next.config.js

@@ -1,5 +0,0 @@
-module.exports = {
-  generateBuildId() {
-    return 'testing-build-id';
-  },
-};

packages/now-next/test/fixtures/22-ssg-v2-shared-lambdas/now.json

@@ -1,146 +0,0 @@
-{
-  "version": 2,
-  "builds": [
-    {
-      "src": "package.json",
-      "use": "@vercel/next",
-      "config": {
-        "sharedLambdas": true
-      }
-    }
-  ],
-  "probes": [
-    {
-      "path": "/lambda",
-      "status": 200,
-      "responseHeaders": {
-        "x-vercel-cache": "MISS"
-      }
-    },
-    {
-      "path": "/forever",
-      "status": 200,
-      "responseHeaders": {
-        "x-vercel-cache": "PRERENDER"
-      }
-    },
-    { "delay": 2000 },
-    {
-      "path": "/forever",
-      "status": 200,
-      "responseHeaders": {
-        "x-vercel-cache": "HIT"
-      }
-    },
-    {
-      "path": "/blog/post-3",
-      "status": 200,
-      "mustContain": "loading..."
-    },
-    { "delay": 2000 },
-    {
-      "path": "/blog/post-3",
-      "status": 200,
-      "responseHeaders": {
-        "x-vercel-cache": "/HIT|STALE/"
-      }
-    },
-    {
-      "path": "/_next/data/testing-build-id/blog/post-4.json",
-      "status": 200,
-      "responseHeaders": {
-        "x-vercel-cache": "MISS"
-      }
-    },
-    { "delay": 2000 },
-    {
-      "path": "/_next/data/testing-build-id/blog/post-4.json",
-      "status": 200,
-      "responseHeaders": {
-        "x-vercel-cache": "/HIT|STALE/"
-      }
-    },
-    {
-      "path": "/blog/post-3",
-      "status": 200,
-      "mustContain": "post-3"
-    },
-    {
-      "path": "/blog/post-3/comment-3",
-      "status": 200,
-      "mustContain": "loading..."
-    },
-    {
-      "path": "/_next/data/testing-build-id/lambda.json",
-      "status": 404
-    },
-    {
-      "path": "/_next/data/testing-build-id/forever.json",
-      "status": 200,
-      "responseHeaders": {
-        "x-vercel-cache": "/PRERENDER|HIT/"
-      }
-    },
-    { "delay": 2000 },
-    {
-      "path": "/blog/post-3/comment-3",
-      "status": 200,
-      "mustContain": "comment-3"
-    },
-    {
-      "path": "/_next/data/testing-build-id/forever.json",
-      "status": 200,
-      "responseHeaders": {
-        "x-vercel-cache": "HIT"
-      }
-    },
-    {
-      "path": "/_next/data/testing-build-id/another2.json",
-      "status": 200,
-      "responseHeaders": {
-        "x-vercel-cache": "PRERENDER"
-      }
-    },
-    { "delay": 2000 },
-    {
-      "path": "/_next/data/testing-build-id/another2.json",
-      "status": 200,
-      "responseHeaders": {
-        "x-vercel-cache": "HIT"
-      }
-    },
-    {
-      "path": "/nofallback/one",
-      "status": 200,
-      "mustContain": "one"
-    },
-    {
-      "path": "/nofallback/two",
-      "status": 200,
-      "mustContain": "two"
-    },
-    {
-      "path": "/nofallback/nope",
-      "status": 404,
-      "mustContain": "This page could not be found"
-    },
-    {
-      "path": "/_next/data/testing-build-id/nofallback/one.json",
-      "status": 200,
-      "responseHeaders": {
-        "x-vercel-cache": "/HIT|STALE|PRERENDER/"
-      }
-    },
-    {
-      "path": "/_next/data/testing-build-id/nofallback/two.json",
-      "status": 200,
-      "responseHeaders": {
-        "x-vercel-cache": "/HIT|STALE|PRERENDER/"
-      }
-    },
-    {
-      "path": "/_next/data/testing-build-id/nofallback/nope.json",
-      "status": 404
-    }
-  ]
-}

packages/now-next/test/fixtures/22-ssg-v2-shared-lambdas/package.json

@@ -1,7 +0,0 @@
-{
-  "dependencies": {
-    "next": "canary",
-    "react": "^16.8.6",
-    "react-dom": "^16.8.6"
-  }
-}

packages/now-next/test/fixtures/22-ssg-v2-shared-lambdas/pages/another.js

@@ -1,23 +0,0 @@
-import React from 'react';
-
-// eslint-disable-next-line camelcase
-export async function getStaticProps() {
-  return {
-    props: {
-      world: 'world',
-      random: Math.random(),
-      time: new Date().getTime(),
-    },
-    unstable_revalidate: 1,
-  };
-}
-
-export default ({ world, time, random }) => {
-  return (
-    <>
-      <p id="hello">hello: {world}</p>
-      <span id="time">time: {time}</span>
-      <span id="random">random: {random}</span>
-    </>
-  );
-};

packages/now-next/test/fixtures/22-ssg-v2-shared-lambdas/pages/another2.js

@@ -1,21 +0,0 @@
-import React from 'react';
-
-// eslint-disable-next-line camelcase
-export async function getStaticProps() {
-  return {
-    props: {
-      world: 'world',
-      time: new Date().getTime(),
-    },
-    unstable_revalidate: 5,
-  };
-}
-
-export default ({ world, time }) => {
-  return (
-    <>
-      <p>hello: {world}</p>
-      <span>time: {time}</span>
-    </>
-  );
-};

packages/now-next/test/fixtures/22-ssg-v2-shared-lambdas/pages/blog/[post]/[comment].js

@@ -1,40 +0,0 @@
-import React from 'react';
-
-// eslint-disable-next-line camelcase
-export async function getStaticPaths() {
-  return {
-    paths: [
-      '/blog/post-1/comment-1',
-      { params: { post: 'post-2', comment: 'comment-2' } },
-      '/blog/post-1337/comment-1337',
-      '/blog/post-123/comment-321'
-    ],
-    fallback: true,
-  };
-}
-
-// eslint-disable-next-line camelcase
-export async function getStaticProps({ params }) {
-  return {
-    props: {
-      post: params.post,
-      random: Math.random(),
-      comment: params.comment,
-      time: new Date().getTime(),
-    },
-    unstable_revalidate: 1,
-  };
-}
-
-export default ({ post, comment, time, random }) => {
-  if (!post) return <p>loading...</p>;
-
-  return (
-    <>
-      <p id='post'>Post: {post}</p>
-      <p id='comment'>Comment: {comment}</p>
-      <span id='time'>time: {time}</span>
-      <span id='random'>random: {random}</span>
-    </>
-  );
-};

packages/now-next/test/fixtures/22-ssg-v2-shared-lambdas/pages/blog/[post]/index.js

@@ -1,43 +0,0 @@
-import React from 'react';
-
-// eslint-disable-next-line camelcase
-export async function getStaticPaths() {
-  return {
-    paths: [
-      '/blog/post-1',
-      { params: { post: 'post-2' } },
-      '/blog/post-123',
-    ],
-    fallback: true,
-  };
-}
-
-// eslint-disable-next-line camelcase
-export async function getStaticProps({ params }) {
-  if (params.post === 'post-10') {
-    await new Promise(resolve => {
-      setTimeout(() => resolve(), 1000);
-    });
-  }
-
-  return {
-    props: {
-      post: params.post,
-      random: Math.random(),
-      time: (await import('perf_hooks')).performance.now(),
-    },
-    unstable_revalidate: 1,
-  };
-}
-
-export default ({ post, time, random }) => {
-  if (!post) return <p>loading...</p>;
-
-  return (
-    <>
-      <p id='post'>Post: {post}</p>
-      <span id='time'>time: {time}</span>
-      <span id='random'>random: {random}</span>
-    </>
-  );
-};

packages/now-next/test/fixtures/22-ssg-v2-shared-lambdas/pages/forever.js

@@ -1,21 +0,0 @@
-import React from 'react';
-
-// eslint-disable-next-line camelcase
-export async function getStaticProps() {
-  return {
-    props: {
-      world: 'world',
-      time: new Date().getTime(),
-    },
-    unstable_revalidate: false,
-  };
-}
-
-export default ({ world, time }) => {
-  return (
-    <>
-      <p>hello: {world}</p>
-      <span>time: {time}</span>
-    </>
-  );
-};

packages/now-next/test/fixtures/22-ssg-v2-shared-lambdas/pages/index.js

@@ -1 +0,0 @@
-export default () => 'Hi';

packages/now-next/test/fixtures/22-ssg-v2-shared-lambdas/pages/lambda.js

@@ -1,5 +0,0 @@
-const Page = ({ data }) => <p>{data} world</p>;
-
-Page.getInitialProps = () => ({ data: 'hello' });
-
-export default Page;

packages/now-next/test/fixtures/22-ssg-v2-shared-lambdas/pages/nofallback/[slug].js

@@ -1,31 +0,0 @@
-import React from 'react';
-
-// eslint-disable-next-line camelcase
-export async function getStaticPaths() {
-  return {
-    paths: ['/nofallback/one', { params: { slug: 'two' } }],
-    fallback: false,
-  };
-}
-
-// eslint-disable-next-line camelcase
-export async function getStaticProps({ params }) {
-  return {
-    props: {
-      slug: params.slug,
-      time: (await import('perf_hooks')).performance.now(),
-    },
-    unstable_revalidate: 10,
-  };
-}
-
-export default ({ slug, time }) => {
-  return (
-    <>
-      <p>
-        Slug ({slug.length}): {slug}
-      </p>
-      <span>time: {time}</span>
-    </>
-  );
-};

packages/now-next/test/fixtures/22-ssg-v2/now.json

@@ -1,5 +1,6 @@
 {
   "version": 2,
+  "uploadNowJson": true,
   "builds": [{ "src": "package.json", "use": "@vercel/next" }],
   "probes": [
     {
@@ -133,6 +134,12 @@
     {
       "path": "/_next/data/testing-build-id/nofallback/nope.json",
       "status": 404
+    },
+    {
+      "logMustNotContain": "WARNING: your application is being opted out of @vercel/next's optimized lambdas mode due to legacy routes"
+    },
+    {
+      "logMustNotContain": "WARNING: Your application is being opted out of \"@vercel/next\" optimized lambdas mode due to `functions` config"
     }
   ]
 }

packages/now-next/test/fixtures/23-custom-routes-verbose-shared-lambdas/.gitignore

@@ -1 +0,0 @@
-!public

packages/now-next/test/fixtures/23-custom-routes-verbose-shared-lambdas/next.config.js

@@ -1,217 +0,0 @@
-module.exports = {
-  generateBuildId() {
-    return 'testing-build-id';
-  },
-  async rewrites() {
-    return [
-      {
-        source: '/to-another',
-        destination: '/another/one',
-      },
-      {
-        source: '/nav',
-        destination: '/404',
-      },
-      {
-        source: '/hello-world',
-        destination: '/static/hello.txt',
-      },
-      {
-        source: '/',
-        destination: '/another',
-      },
-      {
-        source: '/another',
-        destination: '/multi-rewrites',
-      },
-      {
-        source: '/first',
-        destination: '/hello',
-      },
-      {
-        source: '/second',
-        destination: '/hello-again',
-      },
-      {
-        source: '/to-hello',
-        destination: '/hello',
-      },
-      {
-        source: '/(.*)-:id(\\d+).html',
-        destination: '/blog/:id',
-      },
-      {
-        source: '/blog/post-1',
-        destination: '/blog/post-2',
-      },
-      {
-        source: '/test/:path',
-        destination: '/:path',
-      },
-      {
-        source: '/test-overwrite/:something/:another',
-        destination: '/params/this-should-be-the-value',
-      },
-      {
-        source: '/params/:something',
-        destination: '/with-params',
-      },
-      {
-        source: '/query-rewrite/:section/:name',
-        destination: '/with-params?first=:section&second=:name',
-      },
-      {
-        source: '/hidden/_next/:path*',
-        destination: '/_next/:path*',
-      },
-      {
-        source: '/api-hello',
-        destination: '/api/hello',
-      },
-      {
-        source: '/api-hello-regex/(.*)',
-        destination: '/api/hello?name=:1',
-      },
-      {
-        source: '/api-hello-param/:name',
-        destination: '/api/hello?hello=:name',
-      },
-      {
-        source: '/api-dynamic-param/:name',
-        destination: '/api/dynamic/:name?hello=:name',
-      },
-      {
-        source: '/:path/post-321',
-        destination: '/with-params',
-      },
-      {
-        source: '/a/catch-all/:path*',
-        destination: '/a/catch-all',
-      },
-    ];
-  },
-  async redirects() {
-    return [
-      {
-        source: '/redirect/me/to-about/:lang',
-        destination: '/:lang/about',
-        permanent: false,
-      },
-      {
-        source: '/docs/router-status/:code',
-        destination: '/docs/v2/network/status-codes#:code',
-        statusCode: 301,
-      },
-      {
-        source: '/docs/github',
-        destination: '/docs/v2/advanced/now-for-github',
-        statusCode: 301,
-      },
-      {
-        source: '/docs/v2/advanced/:all(.*)',
-        destination: '/docs/v2/more/:all',
-        statusCode: 301,
-      },
-      {
-        source: '/hello/:id/another',
-        destination: '/blog/:id',
-        permanent: false,
-      },
-      {
-        source: '/redirect1',
-        destination: '/',
-        permanent: false,
-      },
-      {
-        source: '/redirect2',
-        destination: '/',
-        statusCode: 301,
-      },
-      {
-        source: '/redirect3',
-        destination: '/another',
-        statusCode: 302,
-      },
-      {
-        source: '/redirect4',
-        destination: '/',
-        permanent: true,
-      },
-      {
-        source: '/redir-chain1',
-        destination: '/redir-chain2',
-        statusCode: 301,
-      },
-      {
-        source: '/redir-chain2',
-        destination: '/redir-chain3',
-        statusCode: 302,
-      },
-      {
-        source: '/redir-chain3',
-        destination: '/',
-        statusCode: 303,
-      },
-      {
-        source: '/to-external',
-        destination: 'https://google.com',
-        permanent: false,
-      },
-      {
-        source: '/query-redirect/:section/:name',
-        destination: '/with-params?first=:section&second=:name',
-        permanent: false,
-      },
-      {
-        source: '/named-like-unnamed/:0',
-        destination: '/:0',
-        permanent: false,
-      },
-      {
-        source: '/redirect-override',
-        destination: '/thank-you-next',
-        permanent: false,
-      },
-    ];
-  },
-
-  async headers() {
-    return [
-      {
-        source: '/add-header',
-        headers: [
-          {
-            key: 'x-custom-header',
-            value: 'hello world',
-          },
-          {
-            key: 'x-another-header',
-            value: 'hello again',
-          },
-        ],
-      },
-      {
-        source: '/my-headers/(.*)',
-        headers: [
-          {
-            key: 'x-first-header',
-            value: 'first',
-          },
-          {
-            key: 'x-second-header',
-            value: 'second',
-          },
-        ],
-      },
-      {
-        source: '/:path*',
-        headers: [
-          {
-            key: 'x-something',
-            value: 'applied-everywhere',
-          },
-        ],
-      },
-    ];
-  },
-};

packages/now-next/test/fixtures/23-custom-routes-verbose-shared-lambdas/now.json

@@ -1,246 +0,0 @@
-{
-  "version": 2,
-  "builds": [
-    {
-      "src": "package.json",
-      "use": "@vercel/next",
-      "config": {
-        "sharedLambdas": true
-      }
-    }
-  ],
-  "probes": [
-    // should handle one-to-one rewrite successfully
-    {
-      "path": "/first",
-      "mustContain": "hello"
-    },
-    // should handle chained rewrites successfully
-    {
-      "path": "/",
-      "mustContain": "multi-rewrites"
-    },
-    // should not match dynamic route immediately after applying header
-    {
-      "path": "/blog/post-321",
-      "mustContain": "with-params"
-    },
-    {
-      "path": "/blog/post-321",
-      "mustNotContain": "post-321"
-    },
-    // should handle chained redirects successfully
-    {
-      "path": "/redir-chain1",
-      "status": 301,
-      "responseHeaders": {
-        "location": "//redir-chain2/"
-      },
-      "fetchOptions": {
-        "redirect": "manual"
-      }
-    },
-    {
-      "path": "/redir-chain2",
-      "status": 302,
-      "responseHeaders": {
-        "location": "//redir-chain3/"
-      },
-      "fetchOptions": {
-        "redirect": "manual"
-      }
-    },
-    {
-      "path": "/redir-chain3",
-      "status": 303,
-      "responseHeaders": {
-        "location": "//$/"
-      },
-      "fetchOptions": {
-        "redirect": "manual"
-      }
-    },
-    // should redirect successfully with permanent: false
-    {
-      "path": "/redirect1",
-      "status": 307,
-      "responseHeaders": {
-        "location": "//$/"
-      },
-      "fetchOptions": {
-        "redirect": "manual"
-      }
-    },
-    // should redirect with params successfully
-    {
-      "path": "/hello/123/another",
-      "status": 307,
-      "responseHeaders": {
-        "location": "//blog/123/"
-      },
-      "fetchOptions": {
-        "redirect": "manual"
-      }
-    },
-    // should redirect with hash successfully
-    {
-      "path": "/docs/router-status/500",
-      "status": 301,
-      "responseHeaders": {
-        "location": "/#500$/"
-      },
-      "fetchOptions": {
-        "redirect": "manual"
-      }
-    },
-    // should redirect successfully with provided statusCode
-    {
-      "path": "/redirect2",
-      "status": 301,
-      "responseHeaders": {
-        "location": "//$/"
-      },
-      "fetchOptions": {
-        "redirect": "manual"
-      }
-    },
-    // should server static files through a rewrite
-    {
-      "path": "/hello-world",
-      "mustContain": "hello world!"
-    },
-    // should rewrite with params successfully
-    {
-      "path": "/test/hello",
-      "mustContain": "Hello"
-    },
-    // should double redirect successfully
-    {
-      "path": "/docs/github",
-      "mustContain": "hi there"
-    },
-    // should allow params in query for rewrite
-    {
-      "path": "/query-rewrite/hello/world?a=b",
-      "mustContain": "\"a\":\"b\""
-    },
-    {
-      "path": "/query-rewrite/hello/world?a=b",
-      "mustContain": "\"section\":\"hello\""
-    },
-    {
-      "path": "/query-rewrite/hello/world?a=b",
-      "mustContain": "\"name\":\"world\""
-    },
-    {
-      "path": "/query-rewrite/hello/world?a=b",
-      "mustContain": "\"first\":\"hello\""
-    },
-    {
-      "path": "/query-rewrite/hello/world?a=b",
-      "mustContain": "\"second\":\"world\""
-    },
-    // should not allow rewrite to override page file
-    {
-      "path": "/nav",
-      "mustContain": "to-hello"
-    },
-    // show allow redirect to override the page
-    {
-      "path": "/redirect-override",
-      "status": 307,
-      "responseHeaders": {
-        "location": "//thank-you-next$/"
-      },
-      "fetchOptions": {
-        "redirect": "manual"
-      }
-    },
-    // should match a page after a rewrite
-    {
-      "path": "/to-hello",
-      "mustContain": "Hello"
-    },
-    // should match dynamic route after rewrite
-    {
-      "path": "/blog/post-1",
-      "mustContain": "post-2"
-    },
-    // should match public file after rewrite
-    {
-      "path": "/blog/data.json",
-      "mustContain": "\"hello\": \"world\""
-    },
-    // should match /_next file after rewrite
-    {
-      "path": "/hidden/_next/__NEXT_SCRIPT__(/hello)",
-      "mustContain": "createElement"
-    },
-    // should allow redirecting to external resource
-    {
-      "path": "/to-external",
-      "status": 307,
-      "responseHeaders": {
-        "location": "/google.com/"
-      },
-      "fetchOptions": {
-        "redirect": "manual"
-      }
-    },
-    // should apply headers for exact match
-    {
-      "path": "/add-header",
-      "responseHeaders": {
-        "x-custom-header": "hello world",
-        "x-another-header": "hello again"
-      }
-    },
-    // should apply headers for multi match
-    {
-      "path": "/my-headers/first",
-      "responseHeaders": {
-        "x-first-header": "first",
-        "x-second-header": "second"
-      }
-    },
-    // should handle basic api rewrite successfully
-    {
-      "path": "/api-hello",
-      "mustContain": "{\"query\":{}}"
-    },
-    // should handle api rewrite with param successfully
-    {
-      "path": "/api-hello-param/hello",
-      "mustContain": "{\"query\":{\"hello\":\"hello\",\"name\":\"hello\"}}"
-    },
-    // should handle encoded value in the pathname correctly
-    {
-      "path": "/redirect/me/to-about/%5Cgoogle.com",
-      "status": 307,
-      "responseHeaders": {
-        "location": "/%5Cgoogle.com/about/"
-      },
-      "fetchOptions": {
-        "redirect": "manual"
-      }
-    },
-    // should apply un-named multi-match correctly
-    {
-      "path": "/hello/post-123.html",
-      "status": 200,
-      "mustContain": "123"
-    },
-    // should rewrite to catch-all with dash in segment name
-    {
-      "path": "/catchall-dash/hello/world",
-      "status": 200,
-      "mustContain": "hello/world"
-    },
-    // should rewrite and normalize catch-all rewrite param
-    {
-      "path": "/a/catch-all/hello/world",
-      "status": 200,
-      "mustContain": "hello/world"
-    }
-  ]
-}

packages/now-next/test/fixtures/23-custom-routes-verbose-shared-lambdas/package.json

@@ -1,7 +0,0 @@
-{
-  "dependencies": {
-    "next": "canary",
-    "react": "^16.8.6",
-    "react-dom": "^16.8.6"
-  }
-}

packages/now-next/test/fixtures/23-custom-routes-verbose-shared-lambdas/pages/a/catch-all.js

@@ -1,9 +0,0 @@
-import { useRouter } from 'next/router';
-
-export default () => <p>{useRouter().query.path?.join('/')}</p>;
-
-export const getServerSideProps = () => {
-  return {
-    props: {},
-  };
-};

packages/now-next/test/fixtures/23-custom-routes-verbose-shared-lambdas/pages/another/[id].js

@@ -1 +0,0 @@
-export default () => 'hi'

packages/now-next/test/fixtures/23-custom-routes-verbose-shared-lambdas/pages/api/dynamic/[slug].js

@@ -1 +0,0 @@
-export default async (req, res) => res.json({ query: req.query })

packages/now-next/test/fixtures/23-custom-routes-verbose-shared-lambdas/pages/api/hello.js

@@ -1 +0,0 @@
-export default async (req, res) => res.json({ query: req.query });

packages/now-next/test/fixtures/23-custom-routes-verbose-shared-lambdas/pages/blog/[post]/index.js

@@ -1,11 +0,0 @@
-import { useRouter } from 'next/router'
-
-const Page = () => (
-  <>
-    <p>post: {useRouter().query.post}</p>
-  </>
-)
-
-Page.getInitialProps = () => ({ hello: 'world' })
-
-export default Page

packages/now-next/test/fixtures/23-custom-routes-verbose-shared-lambdas/pages/catchall-dash/[...hello-world].js

@@ -1,17 +0,0 @@
-import { useRouter } from 'next/router'
-
-const Page = () => {
-  return (
-    <p>path: {useRouter().query['hello-world']?.join('/')}</p>
-  )
-}
-
-export default Page
-
-export const getServerSideProps = () => {
-  return {
-    props: {
-      hello: 'world'
-    }
-  }
-}

packages/now-next/test/fixtures/23-custom-routes-verbose-shared-lambdas/pages/dash/[hello-world].js

@@ -1 +0,0 @@
-export default () => 'hi'

packages/now-next/test/fixtures/23-custom-routes-verbose-shared-lambdas/pages/docs/v2/more/now-for-github.js

@@ -1 +0,0 @@
-export default () => 'hi there';

packages/now-next/test/fixtures/23-custom-routes-verbose-shared-lambdas/pages/hello-again.js

@@ -1,10 +0,0 @@
-import Link from 'next/link';
-
-export default () => (
-  <>
-    <h3 id="hello-again">Hello again</h3>
-    <Link href="/nav">
-      <a id="to-nav">to nav</a>
-    </Link>
-  </>
-);

packages/now-next/test/fixtures/23-custom-routes-verbose-shared-lambdas/pages/hello.js

@@ -1,14 +0,0 @@
-import Link from 'next/link';
-
-const Page = () => (
-  <>
-    <h3 id="hello">Hello</h3>
-    <Link href="/nav">
-      <a id="to-nav">to nav</a>
-    </Link>
-  </>
-);
-
-Page.getInitialProps = () => ({ hello: 'world' });
-
-export default Page;

packages/now-next/test/fixtures/23-custom-routes-verbose-shared-lambdas/pages/multi-rewrites.js

@@ -1 +0,0 @@
-export default () => 'multi-rewrites';

packages/now-next/test/fixtures/23-custom-routes-verbose-shared-lambdas/pages/nav.js

@@ -1,13 +0,0 @@
-import Link from 'next/link';
-
-export default () => (
-  <>
-    <h3 id="nav">Nav</h3>
-    <Link href="/hello" as="/first">
-      <a id="to-hello">to hello</a>
-    </Link>
-    <Link href="/hello-again" as="/second">
-      <a id="to-hello-again">to hello-again</a>
-    </Link>
-  </>
-);

packages/now-next/test/fixtures/23-custom-routes-verbose-shared-lambdas/pages/params.js

@@ -1,10 +0,0 @@
-import { useRouter } from 'next/router';
-
-const Page = () => {
-  const { query } = useRouter();
-  return <p>{JSON.stringify(query)}</p>;
-};
-
-Page.getInitialProps = () => ({ a: 'b' });
-
-export default Page;

packages/now-next/test/fixtures/23-custom-routes-verbose-shared-lambdas/pages/redirect-override.js

@@ -1 +0,0 @@
-export default () => 'got to the page';

packages/now-next/test/fixtures/23-custom-routes-verbose-shared-lambdas/pages/with-params.js

@@ -1,10 +0,0 @@
-import { useRouter } from 'next/router';
-
-const Page = () => {
-  const { query } = useRouter();
-  return <p>{JSON.stringify(query)}</p>;
-};
-
-Page.getInitialProps = () => ({ hello: 'GIPGIP' });
-
-export default Page;

packages/now-next/test/fixtures/23-custom-routes-verbose-shared-lambdas/public/blog/data.json

@@ -1,3 +0,0 @@
-{
-  "hello": "world"
-}

packages/now-next/test/fixtures/23-custom-routes-verbose-shared-lambdas/public/static/hello.txt

@@ -1 +0,0 @@
-hello world!

packages/now-next/test/fixtures/25-mono-repo-404/vercel.json

@@ -1,5 +1,6 @@
 {
   "version": 2,
+  "uploadNowJson": true,
   "routes": [
     { "src": "/(.*)", "dest": "/packages/webapp/$1", "continue": true }
   ],
@@ -31,6 +32,9 @@
     {
       "path": "/non-existent",
       "status": 404
+    },
+    {
+      "logMustContain": "WARNING: your application is being opted out of @vercel/next's optimized lambdas mode due to legacy routes"
     }
   ]
 }

packages/now-next/test/fixtures/26-mono-repo-404-lambda/now.json

@@ -1,5 +1,6 @@
 {
   "version": 2,
+  "uploadNowJson": true,
   "routes": [
     { "src": "/(.*)", "dest": "/packages/webapp/$1", "continue": true }
   ],
@@ -25,6 +26,9 @@
     {
       "path": "/non-existent",
       "status": 404
+    },
+    {
+      "logMustContain": "WARNING: your application is being opted out of @vercel/next's optimized lambdas mode due to legacy routes"
     }
   ]
 }

packages/now-next/test/integration/index.test.js

@@ -15,8 +15,8 @@ it(
       buildResult: { output },
     } = await runBuildLambda(path.join(__dirname, 'standard'));
     expect(output['index']).toBeDefined();
-    expect(output.goodbye).toBeDefined();
+    expect(output.goodbye).not.toBeDefined();
-    expect(output.__NEXT_PAGE_LAMBDA_0).not.toBeDefined();
+    expect(output.__NEXT_PAGE_LAMBDA_0).toBeDefined();
     const filePaths = Object.keys(output);
     const serverlessError = filePaths.some(filePath =>
       filePath.match(/_error/)
@@ -34,27 +34,29 @@ it(
   FOUR_MINUTES
 );
 
-// it(
+it(
-//   'Should opt-out of shared lambdas when routes are detected',
+  'Should opt-out of shared lambdas when routes are detected',
-//   async () => {
+  async () => {
-//     const {
+    const {
-//       buildResult: { output },
+      buildResult: { output },
-//     } = await runBuildLambda(path.join(__dirname, '../fixtures/26-mono-repo-404-lambda'));
+    } = await runBuildLambda(
-//     expect(output['packages/webapp/404']).toBeDefined();
+      path.join(__dirname, '../fixtures/26-mono-repo-404-lambda')
-//     expect(output['packages/webapp/index']).toBeDefined();
+    );
-//     expect(output['packages/webapp/__NEXT_PAGE_LAMBDA_0']).not.toBeDefined();
+    expect(output['packages/webapp/404']).toBeDefined();
-//     const filePaths = Object.keys(output);
+    expect(output['packages/webapp/index']).toBeDefined();
-//     const hasUnderScoreAppStaticFile = filePaths.some(filePath =>
+    expect(output['packages/webapp/__NEXT_PAGE_LAMBDA_0']).not.toBeDefined();
-//       filePath.match(/static.*\/pages\/_app\.js$/)
+    const filePaths = Object.keys(output);
-//     );
+    const hasUnderScoreAppStaticFile = filePaths.some(filePath =>
-//     const hasUnderScoreErrorStaticFile = filePaths.some(filePath =>
+      filePath.match(/static.*\/pages\/_app\.js$/)
-//       filePath.match(/static.*\/pages\/_error\.js$/)
+    );
-//     );
+    const hasUnderScoreErrorStaticFile = filePaths.some(filePath =>
-//     expect(hasUnderScoreAppStaticFile).toBeTruthy();
+      filePath.match(/static.*\/pages\/_error\.js$/)
-//     expect(hasUnderScoreErrorStaticFile).toBeTruthy();
+    );
-//   },
+    expect(hasUnderScoreAppStaticFile).toBeTruthy();
-//   FOUR_MINUTES
+    expect(hasUnderScoreErrorStaticFile).toBeTruthy();
-// );
+  },
+  FOUR_MINUTES
+);
 
 it(
   'Should build the monorepo example',
@@ -63,8 +65,8 @@ it(
       buildResult: { output },
     } = await runBuildLambda(path.join(__dirname, 'monorepo'));
 
-    expect(output['www/index']).toBeDefined();
+    expect(output['www/index']).not.toBeDefined();
-    expect(output['www/__NEXT_PAGE_LAMBDA_0']).not.toBeDefined();
+    expect(output['www/__NEXT_PAGE_LAMBDA_0']).toBeDefined();
     expect(output['www/static/test.txt']).toBeDefined();
     expect(output['www/data.txt']).toBeDefined();
     const filePaths = Object.keys(output);
@@ -164,9 +166,9 @@ it(
       buildResult: { output },
     } = await runBuildLambda(path.join(__dirname, 'serverless-config'));
 
-    expect(output.index).toBeDefined();
+    expect(output.index).not.toBeDefined();
-    expect(output.goodbye).toBeDefined();
+    expect(output.goodbye).not.toBeDefined();
-    expect(output.__NEXT_PAGE_LAMBDA_0).not.toBeDefined();
+    expect(output.__NEXT_PAGE_LAMBDA_0).toBeDefined();
     const filePaths = Object.keys(output);
     const serverlessError = filePaths.some(filePath =>
       filePath.match(/_error/)
@@ -201,9 +203,9 @@ it(
       path.join(__dirname, 'serverless-config-monorepo-missing')
     );
 
-    expect(output['nested/index']).toBeDefined();
+    expect(output['nested/index']).not.toBeDefined();
-    expect(output['nested/goodbye']).toBeDefined();
+    expect(output['nested/goodbye']).not.toBeDefined();
-    expect(output['nested/__NEXT_PAGE_LAMBDA_0']).not.toBeDefined();
+    expect(output['nested/__NEXT_PAGE_LAMBDA_0']).toBeDefined();
     const filePaths = Object.keys(output);
     const serverlessError = filePaths.some(filePath =>
       filePath.match(/_error/)
@@ -235,9 +237,9 @@ it(
       path.join(__dirname, 'serverless-config-monorepo-present')
     );
 
-    expect(output['nested/index']).toBeDefined();
+    expect(output['nested/index']).not.toBeDefined();
-    expect(output['nested/goodbye']).toBeDefined();
+    expect(output['nested/goodbye']).not.toBeDefined();
-    expect(output['nested/__NEXT_PAGE_LAMBDA_0']).not.toBeDefined();
+    expect(output['nested/__NEXT_PAGE_LAMBDA_0']).toBeDefined();
     const filePaths = Object.keys(output);
     const serverlessError = filePaths.some(filePath =>
       filePath.match(/_error/)
@@ -303,8 +305,8 @@ it(
     } = await runBuildLambda(path.join(__dirname, 'serverless-config-object'));
 
     expect(output['index']).toBeDefined();
-    expect(output.goodbye).toBeDefined();
+    expect(output.goodbye).not.toBeDefined();
-    expect(output.__NEXT_PAGE_LAMBDA_0).not.toBeDefined();
+    expect(output.__NEXT_PAGE_LAMBDA_0).toBeDefined();
     const filePaths = Object.keys(output);
     const serverlessError = filePaths.some(filePath =>
       filePath.match(/_error/)
@@ -338,8 +340,8 @@ it(
     } = await runBuildLambda(path.join(__dirname, 'serverless-no-config'));
 
     expect(output['index']).toBeDefined();
-    expect(output.goodbye).toBeDefined();
+    expect(output.goodbye).not.toBeDefined();
-    expect(output.__NEXT_PAGE_LAMBDA_0).not.toBeDefined();
+    expect(output.__NEXT_PAGE_LAMBDA_0).toBeDefined();
     const filePaths = Object.keys(output);
     const serverlessError = filePaths.some(filePath =>
       filePath.match(/_error/)

packages/now-next/test/test.js

@@ -24,9 +24,12 @@ beforeAll(async () => {
   }
 
   process.env.NEXT_TELEMETRY_DISABLED = '1';
-  const builderPath = path.resolve(__dirname, '..');
+
-  builderUrl = await packAndDeploy(builderPath);
+  if (!builderUrl) {
-  console.log('builderUrl', builderUrl);
+    const builderPath = path.resolve(__dirname, '..');
+    builderUrl = await packAndDeploy(builderPath);
+    console.log('builderUrl', builderUrl);
+  }
 });
 
 const fixturesPath = path.resolve(__dirname, 'fixtures');

test/lib/deployment/now-deploy.js

@@ -5,9 +5,11 @@ const _fetch = require('node-fetch');
 const fetch = require('./fetch-retry.js');
 const sleep = ms => new Promise(resolve => setTimeout(resolve, ms));
 
-async function nowDeploy(bodies, randomness) {
+async function nowDeploy(bodies, randomness, uploadNowJson) {
   const files = Object.keys(bodies)
-    .filter(n => n !== 'vercel.json' && n !== 'now.json')
+    .filter(n =>
+      uploadNowJson ? true : n !== 'vercel.json' && n !== 'now.json'
+    )
     .map(n => ({
       sha: digestOfFile(bodies[n]),
       size: bodies[n].length,

test/lib/deployment/test-deployment.js

@@ -57,6 +57,8 @@ async function testDeployment(
 
   // we use json5 to allow comments for probes
   const nowJson = json5.parse(bodies[configName]);
+  const uploadNowJson = nowJson.uploadNowJson;
+  delete nowJson.uploadNowJson;
 
   if (process.env.VERCEL_BUILDER_DEBUG) {
     if (!nowJson.build) {
@@ -94,8 +96,14 @@ async function testDeployment(
 
   bodies[configName] = Buffer.from(JSON.stringify(nowJson));
   delete bodies['probe.js'];
-  const { deploymentId, deploymentUrl } = await nowDeploy(bodies, randomness);
+
+  const { deploymentId, deploymentUrl } = await nowDeploy(
+    bodies,
+    randomness,
+    uploadNowJson
+  );
   let nextBuildManifest;
+  let deploymentLogs;
 
   for (const probe of nowJson.probes || []) {
     console.log('testing', JSON.stringify(probe));
@@ -104,6 +112,60 @@ async function testDeployment(
       continue;
     }
 
+    if (probe.logMustContain || probe.logMustNotContain) {
+      const shouldContain = !!probe.logMustContain;
+      const toCheck = probe.logMustContain || probe.logMustNotContain;
+
+      if (probe.logMustContain && probe.logMustNotContain) {
+        throw new Error(
+          `probe can not check logMustContain and logMustNotContain in the same check`
+        );
+      }
+
+      if (!deploymentLogs) {
+        try {
+          const logsRes = await fetch(
+            `https://vercel.com/api/v1/now/deployments/${deploymentId}/events?limit=-1`
+          );
+
+          if (!logsRes.ok) {
+            throw new Error(
+              `fetching logs failed with status ${logsRes.status}`
+            );
+          }
+          deploymentLogs = await logsRes.json();
+        } catch (err) {
+          throw new Error(
+            `Failed to get deployment logs for probe: ${err.message}`
+          );
+        }
+      }
+
+      let found = false;
+
+      for (const log of deploymentLogs) {
+        if (log.text && log.text.includes(toCheck)) {
+          if (shouldContain) {
+            found = true;
+            break;
+          } else {
+            throw new Error(
+              `Expected deployment logs not to contain ${toCheck}, but found ${log.text}`
+            );
+          }
+        }
+      }
+
+      if (!found && shouldContain) {
+        throw new Error(
+          `Expected deployment logs to contain ${toCheck}, it was not found`
+        );
+      } else {
+        console.log('finished testing', JSON.stringify(probe));
+        continue;
+      }
+    }
+
     const nextScriptIndex = probe.path.indexOf('__NEXT_SCRIPT__(');
 
     if (nextScriptIndex > -1) {

yarn.lock

@@ -2190,6 +2190,11 @@
     semver "^7.3.2"
     tsutils "^3.17.1"
 
+"@vercel/static-build@0.17.4-canary.1":
+  version "0.17.4-canary.1"
+  resolved "https://registry.yarnpkg.com/@vercel/static-build/-/static-build-0.17.4-canary.1.tgz#42ba89d5dee7ced3a20ec0a3a2986d293405530a"
+  integrity sha512-SWvu9zm6sQGuQeouHDnxOYxDlgvKSk7pb4m2QuVufFXrhOkx7OL6e91riHXCpmscv8Pb9mD7DFVl2o78FK7viA==
+
 "@zeit/dns-cached-resolve@2.1.0":
   version "2.1.0"
   resolved "https://registry.yarnpkg.com/@zeit/dns-cached-resolve/-/dns-cached-resolve-2.1.0.tgz#78583010df1683fdb7b05949b75593c9a8641bc1"