Publish Stable

- @vercel/build-utils@5.0.0 - vercel@26.0.0 - @vercel/client@12.0.4 - @vercel/fs-detectors@1.0.0 - @vercel/go@2.0.4 - @vercel/next@3.1.3 - @vercel/node@2.4.0 - @vercel/python@3.0.4 - @vercel/redwood@1.0.5 - @vercel/remix@1.0.5 - @vercel/ruby@1.3.12 - @vercel/static-build@1.0.4
Update trailing slash handling for _next/data resolving (#8080 )
2025-12-11 12:57:46 +00:00 · 2022-07-05 08:47:49 -04:00 · 2022-07-04 09:52:08 -05:00 · 2022-07-04 13:22:35 +00:00 · 2022-07-01 22:47:36 +00:00 · 2022-07-01 20:38:02 +00:00
335 changed files with 19648 additions and 11937 deletions
--- a/.prettierignore
+++ b/.prettierignore
@@ -0,0 +1,4 @@
+# https://prettier.io/docs/en/ignore.html
+
+# ignore this file with an intentional syntax error
+packages/cli/test/dev/fixtures/edge-function-error/api/edge-error-syntax.js
--- a/.vercelignore
+++ b/.vercelignore
@@ -1,18 +1 @@
-*
-
-# general
-!utils/
-!utils/run.js
-!.yarnrc
-!yarn.lock
-!package.json
-!turbo.json
-
-# api
-!api/
-!api/**
-
-# packages
-!packages/
-!packages/frameworks
-!packages/frameworks/**
+packages/*/test/**
--- a/api/_lib/script/build.ts
+++ b/api/_lib/script/build.ts
@@ -1,5 +1,6 @@
 import fs from 'fs/promises';
-import { join } from 'path';
+import { join, dirname } from 'path';
+import execa from 'execa';
 import { getExampleList } from '../examples/example-list';
 import { mapOldToNew } from '../examples/map-old-to-new';

@@ -40,7 +41,32 @@ async function main() {
    JSON.stringify([...existingExamples, ...oldExamples])
  );

+  const { stdout: sha } = await execa('git', ['rev-parse', '--short', 'HEAD'], {
+    cwd: repoRoot,
+  });
+
+  const tarballsDir = join(pubDir, 'tarballs');
+  const packagesDir = join(repoRoot, 'packages');
+  const packages = await fs.readdir(packagesDir);
+  for (const pkg of packages) {
+    const fullDir = join(packagesDir, pkg);
+    const packageJsonRaw = await fs.readFile(
+      join(fullDir, 'package.json'),
+      'utf-8'
+    );
+    const packageJson = JSON.parse(packageJsonRaw);
+    const tarballName = `${packageJson.name
+      .replace('@', '')
+      .replace('/', '-')}-v${packageJson.version}-${sha.trim()}.tgz`;
+    const destTarballPath = join(tarballsDir, `${packageJson.name}.tgz`);
+    await fs.mkdir(dirname(destTarballPath), { recursive: true });
+    await fs.copyFile(join(fullDir, tarballName), destTarballPath);
+  }
+
  console.log('Completed building static frontend.');
 }

-main().catch(console.error);
+main().catch(err => {
+  console.log('error running build:', err);
+  process.exit(1);
+});
--- a/examples/create-react-app/src/vitals.js
+++ b/examples/create-react-app/src/vitals.js
@@ -24,7 +24,6 @@ export function sendToVercelAnalytics(metric) {
    speed: getConnectionSpeed(),
  };

-  console.log({ body });
  const blob = new Blob([new URLSearchParams(body).toString()], {
    // This content type is necessary for `sendBeacon`
    type: 'application/x-www-form-urlencoded',
--- a/examples/remix/.eslintrc.js
+++ b/examples/remix/.eslintrc.js
@@ -0,0 +1,3 @@
+module.exports = {
+  extends: ["@remix-run/eslint-config", "@remix-run/eslint-config/node"],
+};
--- a/examples/remix/.gitignore
+++ b/examples/remix/.gitignore
@@ -1,7 +1,11 @@
 node_modules

 .cache
+.env
 .vercel
+.output

-public/build
-api/_build
+/build/
+/public/build
+/api/index.js
+/api/index.js.map
--- a/examples/remix/api/index.js
+++ b/examples/remix/api/index.js
@@ -1,5 +0,0 @@
-const { createRequestHandler } = require("@remix-run/vercel");
-
-module.exports = createRequestHandler({
-  build: require("./_build")
-});
--- a/examples/remix/app/entry.client.tsx
+++ b/examples/remix/app/entry.client.tsx
@@ -1,4 +1,4 @@
+import { RemixBrowser } from "@remix-run/react";
 import { hydrate } from "react-dom";
-import { RemixBrowser } from "remix";

 hydrate(<RemixBrowser />, document);
--- a/examples/remix/app/entry.server.tsx
+++ b/examples/remix/app/entry.server.tsx
@@ -1,6 +1,6 @@
+import type { EntryContext } from "@remix-run/node";
+import { RemixServer } from "@remix-run/react";
 import { renderToString } from "react-dom/server";
-import { RemixServer } from "remix";
-import type { EntryContext } from "remix";

 export default function handleRequest(
  request: Request,
@@ -16,6 +16,6 @@ export default function handleRequest(

  return new Response("<!DOCTYPE html>" + markup, {
    status: responseStatusCode,
-    headers: responseHeaders
+    headers: responseHeaders,
  });
 }
--- a/examples/remix/app/root.tsx
+++ b/examples/remix/app/root.tsx
@@ -1,3 +1,4 @@
+import type { LinksFunction, MetaFunction } from "@remix-run/node";
 import {
  Link,
  Links,
@@ -6,14 +7,13 @@ import {
  Outlet,
  Scripts,
  ScrollRestoration,
-  useCatch
-} from "remix";
-import type { LinksFunction } from "remix";
+  useCatch,
+} from "@remix-run/react";

-import globalStylesUrl from "~/styles/global.css";
 import darkStylesUrl from "~/styles/dark.css";
+import globalStylesUrl from "~/styles/global.css";

-// https://remix.run/api/app#links
+// https://remix.run/api/conventions#links
 export let links: LinksFunction = () => {
  return [
    { rel: "stylesheet", href: globalStylesUrl },
@@ -25,6 +25,12 @@ export let links: LinksFunction = () => {
  ];
 };

+// https://remix.run/api/conventions#meta
+export let meta: MetaFunction = () => ({
+  charset: "utf-8",
+  viewport: "width=device-width,initial-scale=1",
+});
+
 // https://remix.run/api/conventions#default-export
 // https://remix.run/api/conventions#route-filenames
 export default function App() {
@@ -37,7 +43,7 @@ export default function App() {
  );
 }

-// https://remix.run/docs/en/v1/api/conventions#errorboundary
+// https://remix.run/api/conventions#errorboundary
 export function ErrorBoundary({ error }: { error: Error }) {
  console.error(error);
  return (
@@ -57,7 +63,7 @@ export function ErrorBoundary({ error }: { error: Error }) {
  );
 }

-// https://remix.run/docs/en/v1/api/conventions#catchboundary
+// https://remix.run/api/conventions#catchboundary
 export function CatchBoundary() {
  let caught = useCatch();

@@ -103,8 +109,6 @@ function Document({
  return (
    <html lang="en">
      <head>
-        <meta charSet="utf-8" />
-        <meta name="viewport" content="width=device-width,initial-scale=1" />
        {title ? <title>{title}</title> : null}
        <Meta />
        <Links />
@@ -113,7 +117,7 @@ function Document({
        {children}
        <ScrollRestoration />
        <Scripts />
-        {process.env.NODE_ENV === "development" && <LiveReload />}
+        <LiveReload />
      </body>
    </html>
  );
--- a/examples/remix/app/routes/demos/about.tsx
+++ b/examples/remix/app/routes/demos/about.tsx
@@ -1,5 +1,5 @@
-import { Outlet } from "remix";
-import type { MetaFunction, LinksFunction } from "remix";
+import type { MetaFunction, LinksFunction } from "@remix-run/node";
+import { Outlet } from "@remix-run/react";

 import stylesUrl from "~/styles/demos/about.css";

--- a/examples/remix/app/routes/demos/about/index.tsx
+++ b/examples/remix/app/routes/demos/about/index.tsx
@@ -1,4 +1,4 @@
-import { Link } from "remix";
+import { Link } from "@remix-run/react";

 export default function AboutIndex() {
  return (
--- a/examples/remix/app/routes/demos/about/whoa.tsx
+++ b/examples/remix/app/routes/demos/about/whoa.tsx
@@ -1,4 +1,4 @@
-import { Link } from "remix";
+import { Link } from "@remix-run/react";

 export default function AboutIndex() {
  return (
--- a/examples/remix/app/routes/demos/actions.tsx
+++ b/examples/remix/app/routes/demos/actions.tsx
@@ -1,6 +1,7 @@
+import type { ActionFunction } from "@remix-run/node";
+import { json, redirect } from "@remix-run/node";
+import { Form, useActionData } from "@remix-run/react";
 import { useEffect, useRef } from "react";
-import type { ActionFunction } from "remix";
-import { Form, json, useActionData, redirect } from "remix";

 export function meta() {
  return { title: "Actions Demo" };
--- a/examples/remix/app/routes/demos/params.tsx
+++ b/examples/remix/app/routes/demos/params.tsx
@@ -1,8 +1,8 @@
-import { useCatch, Link, json, useLoaderData, Outlet } from "remix";
+import type { MetaFunction } from "@remix-run/node";
+import { json } from "@remix-run/node";
+import { Link, Outlet, useCatch, useLoaderData } from "@remix-run/react";

-export function meta() {
-  return { title: "Boundaries Demo" };
-}
+export let meta: MetaFunction = () => ({ title: "Boundaries Demo" });

 export default function Boundaries() {
  return (
--- a/examples/remix/app/routes/demos/params/$id.tsx
+++ b/examples/remix/app/routes/demos/params/$id.tsx
@@ -1,5 +1,6 @@
-import { useCatch, Link, json, useLoaderData } from "remix";
-import type { LoaderFunction, MetaFunction } from "remix";
+import type { LoaderFunction, MetaFunction } from "@remix-run/node";
+import { json } from "@remix-run/node";
+import { Link, useCatch, useLoaderData } from "@remix-run/react";

 // The `$` in route filenames becomes a pattern that's parsed from the URL and
 // passed to your loaders so you can look up data.
--- a/examples/remix/app/routes/demos/params/index.tsx
+++ b/examples/remix/app/routes/demos/params/index.tsx
@@ -1,5 +1,6 @@
-import { useCatch, Link, json, useLoaderData, Outlet } from "remix";
-import type { LoaderFunction } from "remix";
+import type { LoaderFunction } from "@remix-run/node";
+import { json } from "@remix-run/node";
+import { Link, Outlet, useCatch, useLoaderData } from "@remix-run/react";

 export default function Boundaries() {
  return (
--- a/examples/remix/app/routes/index.tsx
+++ b/examples/remix/app/routes/index.tsx
@@ -1,5 +1,6 @@
-import type { MetaFunction, LoaderFunction } from "remix";
-import { useLoaderData, json, Link } from "remix";
+import type { MetaFunction, LoaderFunction } from "@remix-run/node";
+import { json } from "@remix-run/node";
+import { Link, useLoaderData } from "@remix-run/react";

 type IndexData = {
  resources: Array<{ name: string; url: string }>;
--- a/examples/remix/package-lock.json
+++ b/examples/remix/package-lock.json
--- a/examples/remix/package.json
+++ b/examples/remix/package.json
@@ -1,26 +1,28 @@
 {
  "private": true,
-  "name": "remix-app-template",
-  "description": "",
-  "license": "",
+  "sideEffects": false,
  "scripts": {
    "build": "remix build",
-    "dev": "remix dev",
-    "postinstall": "remix setup node"
+    "dev": "remix dev"
  },
  "dependencies": {
-    "@remix-run/react": "^1.0.6",
+    "@remix-run/node": "^1.5.1",
+    "@remix-run/react": "^1.5.1",
+    "@remix-run/vercel": "^1.5.1",
+    "@vercel/node": "^2.0.0",
    "react": "^17.0.2",
-    "react-dom": "^17.0.2",
-    "remix": "^1.0.6",
-    "@remix-run/serve": "^1.0.6",
-    "@remix-run/vercel": "^1.0.6"
+    "react-dom": "^17.0.2"
  },
  "devDependencies": {
-    "@remix-run/dev": "^1.0.6",
-    "@types/react": "^17.0.24",
-    "@types/react-dom": "^17.0.9",
-    "typescript": "^4.1.2"
+    "@remix-run/dev": "^1.5.1",
+    "@remix-run/eslint-config": "^1.5.1",
+    "@remix-run/serve": "^1.5.1",
+    "@types/react": "^17.0.45",
+    "@types/react-dom": "^17.0.17",
+    "eslint": "^8.15.0",
+    "typescript": "^4.6.4"
  },
-  "sideEffects": false
+  "engines": {
+    "node": ">=14"
+  }
 }
--- a/examples/remix/remix.config.js
+++ b/examples/remix/remix.config.js
@@ -1,9 +1,15 @@
 /**
- * @type {import('@remix-run/dev/config').AppConfig}
+ * @type {import('@remix-run/dev').AppConfig}
 */
 module.exports = {
-  appDirectory: "app",
-  browserBuildDirectory: "public/build",
-  publicPath: "/build/",
-  serverBuildDirectory: "api/_build"
+  serverBuildTarget: "vercel",
+  // When running locally in development mode, we use the built in remix
+  // server. This does not understand the vercel lambda module format,
+  // so we default back to the standard build output.
+  server: process.env.NODE_ENV === "development" ? undefined : "./server.js",
+  ignoredRouteFiles: ["**/.*"],
+  // appDirectory: "app",
+  // assetsBuildDirectory: "public/build",
+  // serverBuildPath: "api/index.js",
+  // publicPath: "/build/",
 };
--- a/examples/remix/server.js
+++ b/examples/remix/server.js
@@ -0,0 +1,4 @@
+import * as build from "@remix-run/dev/server-build";
+import { createRequestHandler } from "@remix-run/vercel";
+
+export default createRequestHandler({ build, mode: process.env.NODE_ENV });
--- a/examples/sveltekit/package.json
+++ b/examples/sveltekit/package.json
@@ -19,7 +19,6 @@
    "prettier-plugin-svelte": "^2.5.0",
    "svelte": "^3.46.0",
    "svelte-check": "^2.2.6",
-    "svelte-preprocess": "^4.10.6",
    "typescript": "~4.6.2"
  },
  "type": "module",
--- a/examples/sveltekit/pnpm-lock.yaml
+++ b/examples/sveltekit/pnpm-lock.yaml
--- a/examples/sveltekit/src/routes/__layout.svelte
+++ b/examples/sveltekit/src/routes/__layout.svelte
@@ -7,14 +7,12 @@

  let analyticsId = import.meta.env.VERCEL_ANALYTICS_ID;

-  if (browser && analyticsId) {
-    page.subscribe(({ url, params }) =>
-      webVitals({
-        path: url.pathname,
-        params,
-        analyticsId
-      })
-    );
+  $: if (browser && analyticsId) {
+    webVitals({
+      path: $page.url.pathname,
+      params: $page.params,
+      analyticsId
+    })
  }
 </script>

--- a/examples/sveltekit/svelte.config.js
+++ b/examples/sveltekit/svelte.config.js
@@ -1,19 +1,18 @@
 import adapter from '@sveltejs/adapter-auto';
-import preprocess from 'svelte-preprocess';

 /** @type {import('@sveltejs/kit').Config} */
 const config = {
-  preprocess: preprocess({
-    replace: [
-      ['import.meta.env.VERCEL_ANALYTICS_ID', JSON.stringify(process.env.VERCEL_ANALYTICS_ID)]
-    ]
-  }),
  kit: {
    adapter: adapter(),

    // Override http methods in the Todo forms
    methodOverride: {
      allowed: ['PATCH', 'DELETE']
+    },
+    vite: {
+      define: {
+        'import.meta.env.VERCEL_ANALYTICS_ID': JSON.stringify(process.env.VERCEL_ANALYTICS_ID)
+      }
    }
  }
 };
--- a/package.json
+++ b/package.json
@@ -31,7 +31,7 @@
    "prettier": "2.6.2",
    "ts-eager": "2.0.2",
    "ts-jest": "28.0.5",
-    "turbo": "1.2.14"
+    "turbo": "1.3.1"
  },
  "scripts": {
    "lerna": "lerna",
@@ -41,7 +41,7 @@
    "publish-from-github": "./utils/publish.sh",
    "changelog": "node utils/changelog.js",
    "build": "turbo run build",
-    "vercel-build": "yarn build && cd api && node -r ts-eager/register ./_lib/script/build.ts",
+    "vercel-build": "yarn build && yarn run pack && cd api && node -r ts-eager/register ./_lib/script/build.ts",
    "pre-commit": "lint-staged",
    "test": "jest --rootDir=\"test\" --testPathPattern=\"\\.test.js\"",
    "test-unit": "yarn test && turbo run test-unit",
@@ -49,7 +49,8 @@
    "test-integration-once": "turbo run test-integration-once",
    "test-integration-dev": "turbo run test-integration-dev",
    "lint": "eslint . --ext .ts,.js",
-    "prepare": "husky install"
+    "prepare": "husky install",
+    "pack": "cd utils && node -r ts-eager/register ./pack.ts"
  },
  "lint-staged": {
    "./{*,{api,packages,test,utils}/**/*}.{js,ts}": [
--- a/packages/build-utils/package.json
+++ b/packages/build-utils/package.json
@@ -1,6 +1,6 @@
 {
  "name": "@vercel/build-utils",
-  "version": "4.1.1-canary.1",
+  "version": "5.0.0",
  "license": "MIT",
  "main": "./dist/index.js",
  "types": "./dist/index.d.js",
@@ -31,7 +31,6 @@
    "@types/node-fetch": "^2.1.6",
    "@types/semver": "6.0.0",
    "@types/yazl": "2.4.2",
-    "@vercel/frameworks": "1.0.2-canary.0",
    "@vercel/ncc": "0.24.0",
    "aggregate-error": "3.0.1",
    "async-retry": "1.2.3",
--- a/packages/build-utils/src/fs/run-user-scripts.ts
+++ b/packages/build-utils/src/fs/run-user-scripts.ts
@@ -61,6 +61,13 @@ export interface SpawnOptionsExtended extends SpawnOptions {
   * Pretty formatted command that is being spawned for logging purposes.
   */
  prettyCommand?: string;
+
+  /**
+   * Returns instead of throwing an error when the process exits with a
+   * non-0 exit code. When relevant, the returned object will include
+   * the error code, stdout and stderr.
+   */
+  ignoreNon0Exit?: boolean;
 }

 export function spawnAsync(
@@ -79,7 +86,7 @@ export function spawnAsync(

    child.on('error', reject);
    child.on('close', (code, signal) => {
-      if (code === 0) {
+      if (code === 0 || opts.ignoreNon0Exit) {
        return resolve();
      }

@@ -123,24 +130,24 @@ export function execAsync(

      child.on('error', reject);
      child.on('close', (code, signal) => {
-        if (code !== 0) {
-          const cmd = opts.prettyCommand
-            ? `Command "${opts.prettyCommand}"`
-            : 'Command';
-
-          return reject(
-            new NowBuildError({
-              code: `BUILD_UTILS_EXEC_${code || signal}`,
-              message: `${cmd} exited with ${code || signal}`,
-            })
-          );
+        if (code === 0 || opts.ignoreNon0Exit) {
+          return resolve({
+            code,
+            stdout: Buffer.concat(stdoutList).toString(),
+            stderr: Buffer.concat(stderrList).toString(),
+          });
        }

-        return resolve({
-          code,
-          stdout: Buffer.concat(stdoutList).toString(),
-          stderr: Buffer.concat(stderrList).toString(),
-        });
+        const cmd = opts.prettyCommand
+          ? `Command "${opts.prettyCommand}"`
+          : 'Command';
+
+        return reject(
+          new NowBuildError({
+            code: `BUILD_UTILS_EXEC_${code || signal}`,
+            message: `${cmd} exited with ${code || signal}`,
+          })
+        );
      });
    }
  );
@@ -166,9 +173,30 @@ export async function execCommand(command: string, options: SpawnOptions = {}) {
  return true;
 }

-export async function getNodeBinPath({ cwd }: { cwd: string }) {
-  const { stdout } = await execAsync('npm', ['bin'], { cwd });
-  return stdout.trim();
+export async function getNodeBinPath({
+  cwd,
+}: {
+  cwd: string;
+}): Promise<string> {
+  const { code, stdout, stderr } = await execAsync('npm', ['bin'], {
+    cwd,
+    prettyCommand: 'npm bin',
+
+    // in some rare cases, we saw `npm bin` exit with a non-0 code, but still
+    // output the right bin path, so we ignore the exit code
+    ignoreNon0Exit: true,
+  });
+
+  const nodeBinPath = stdout.trim();
+
+  if (path.isAbsolute(nodeBinPath)) {
+    return nodeBinPath;
+  }
+
+  throw new NowBuildError({
+    code: `BUILD_UTILS_GET_NODE_BIN_PATH`,
+    message: `Running \`npm bin\` failed to return a valid bin path (code=${code}, stdout=${stdout}, stderr=${stderr})`,
+  });
 }

 async function chmodPlusX(fsPath: string) {
@@ -205,10 +233,23 @@ export function getSpawnOptions(
  };

  if (!meta.isDev) {
-    // Ensure that the selected Node version is at the beginning of the `$PATH`
-    opts.env.PATH = `/node${nodeVersion.major}/bin${path.delimiter}${
-      opts.env.PATH || process.env.PATH
-    }`;
+    let found = false;
+    const oldPath = opts.env.PATH || process.env.PATH || '';
+
+    const pathSegments = oldPath.split(path.delimiter).map(segment => {
+      if (/^\/node[0-9]+\/bin/.test(segment)) {
+        found = true;
+        return `/node${nodeVersion.major}/bin`;
+      }
+      return segment;
+    });
+
+    if (!found) {
+      // If we didn't find & replace, prepend at beginning of PATH
+      pathSegments.unshift(`/node${nodeVersion.major}/bin`);
+    }
+
+    opts.env.PATH = pathSegments.filter(Boolean).join(path.delimiter);
  }

  return opts;
@@ -446,20 +487,31 @@ export function getEnvForPackageManager({
  env: { [x: string]: string | undefined };
 }) {
  const newEnv: { [x: string]: string | undefined } = { ...env };
+  const oldPath = env.PATH + '';
+  const npm7 = '/node16/bin-npm7';
+  const pnpm7 = '/pnpm7/node_modules/.bin';
+  const corepackEnabled = env.ENABLE_EXPERIMENTAL_COREPACK === '1';
  if (cliType === 'npm') {
    if (
      typeof lockfileVersion === 'number' &&
      lockfileVersion >= 2 &&
-      (nodeVersion?.major || 0) < 16
+      (nodeVersion?.major || 0) < 16 &&
+      !oldPath.includes(npm7) &&
+      !corepackEnabled
    ) {
      // Ensure that npm 7 is at the beginning of the `$PATH`
-      newEnv.PATH = `/node16/bin-npm7${path.delimiter}${env.PATH}`;
-      console.log('Detected `package-lock.json` generated by npm 7...');
+      newEnv.PATH = `${npm7}${path.delimiter}${oldPath}`;
+      console.log('Detected `package-lock.json` generated by npm 7+...');
    }
  } else if (cliType === 'pnpm') {
-    if (typeof lockfileVersion === 'number' && lockfileVersion === 5.4) {
+    if (
+      typeof lockfileVersion === 'number' &&
+      lockfileVersion === 5.4 &&
+      !oldPath.includes(pnpm7) &&
+      !corepackEnabled
+    ) {
      // Ensure that pnpm 7 is at the beginning of the `$PATH`
-      newEnv.PATH = `/pnpm7/node_modules/.bin${path.delimiter}${env.PATH}`;
+      newEnv.PATH = `${pnpm7}${path.delimiter}${oldPath}`;
      console.log('Detected `pnpm-lock.yaml` generated by pnpm 7...');
    }
  } else {
--- a/packages/build-utils/src/index.ts
+++ b/packages/build-utils/src/index.ts
@@ -80,16 +80,6 @@ export {
 };

 export { EdgeFunction } from './edge-function';
-export {
-  detectBuilders,
-  detectOutputDirectory,
-  detectApiDirectory,
-  detectApiExtensions,
-} from './detect-builders';
-export { detectFileSystemAPI } from './detect-file-system-api';
-export { detectFramework } from './detect-framework';
-export { getProjectPaths } from './get-project-paths';
-export { DetectorFilesystem } from './detectors/filesystem';
 export { readConfigFile } from './fs/read-config-file';
 export { normalizePath } from './fs/normalize-path';

@@ -97,35 +87,3 @@ export * from './should-serve';
 export * from './schemas';
 export * from './types';
 export * from './errors';
-
-/**
- * Helper function to support both `@vercel` and legacy `@now` official Runtimes.
- */
-export const isOfficialRuntime = (desired: string, name?: string): boolean => {
-  if (typeof name !== 'string') {
-    return false;
-  }
-  return (
-    name === `@vercel/${desired}` ||
-    name === `@now/${desired}` ||
-    name.startsWith(`@vercel/${desired}@`) ||
-    name.startsWith(`@now/${desired}@`)
-  );
-};
-
-export const isStaticRuntime = (name?: string): boolean => {
-  return isOfficialRuntime('static', name);
-};
-
-export { workspaceManagers } from './workspaces/workspace-managers';
-export {
-  getWorkspaces,
-  GetWorkspaceOptions,
-  Workspace,
-  WorkspaceType,
-} from './workspaces/get-workspaces';
-export {
-  getWorkspacePackagePaths,
-  GetWorkspacePackagePathsOptions,
-} from './workspaces/get-workspace-package-paths';
-export { monorepoManagers } from './monorepos/monorepo-managers';
--- a/packages/build-utils/test/convert-runtime/invalid-functions/api/users.rb
+++ b/packages/build-utils/test/convert-runtime/invalid-functions/api/users.rb
@@ -1 +0,0 @@
-# users.rb
--- a/packages/build-utils/test/convert-runtime/invalid-functions/vercel.json
+++ b/packages/build-utils/test/convert-runtime/invalid-functions/vercel.json
@@ -1,10 +0,0 @@
-{
-  "functions": {
-    "api/users.rb": {
-      "memory": 3008
-    },
-    "api/doesnt-exist.rb": {
-      "memory": 768
-    }
-  }
-}
--- a/packages/build-utils/test/convert-runtime/python-api/api/db/[id].py
+++ b/packages/build-utils/test/convert-runtime/python-api/api/db/[id].py
@@ -1 +0,0 @@
-# [id].py
--- a/packages/build-utils/test/convert-runtime/python-api/api/index.py
+++ b/packages/build-utils/test/convert-runtime/python-api/api/index.py
@@ -1 +0,0 @@
-# index
--- a/packages/build-utils/test/convert-runtime/python-api/api/project/[aid]/[bid]/index.py
+++ b/packages/build-utils/test/convert-runtime/python-api/api/project/[aid]/[bid]/index.py
@@ -1 +0,0 @@
-# project/[aid]/[bid]/index.py
--- a/packages/build-utils/test/convert-runtime/python-api/api/users/get.py
+++ b/packages/build-utils/test/convert-runtime/python-api/api/users/get.py
@@ -1 +0,0 @@
-# get
--- a/packages/build-utils/test/convert-runtime/python-api/api/users/post.py
+++ b/packages/build-utils/test/convert-runtime/python-api/api/users/post.py
@@ -1 +0,0 @@
-# post
--- a/packages/build-utils/test/convert-runtime/python-api/file.txt
+++ b/packages/build-utils/test/convert-runtime/python-api/file.txt
@@ -1 +0,0 @@
-This file should also be included
--- a/packages/build-utils/test/convert-runtime/python-api/util/date.py
+++ b/packages/build-utils/test/convert-runtime/python-api/util/date.py
@@ -1 +0,0 @@
-# date
--- a/packages/build-utils/test/convert-runtime/python-api/util/math.py
+++ b/packages/build-utils/test/convert-runtime/python-api/util/math.py
@@ -1 +0,0 @@
-# math
--- a/packages/build-utils/test/convert-runtime/python-api/vercel.json
+++ b/packages/build-utils/test/convert-runtime/python-api/vercel.json
@@ -1,7 +0,0 @@
-{
-  "functions": {
-    "api/users/post.py": {
-      "memory": 3008
-    }
-  }
-}
--- a/packages/build-utils/test/integration.test.ts
+++ b/packages/build-utils/test/integration.test.ts
@@ -5,7 +5,6 @@ import {
  testDeployment,
  // @ts-ignore
 } from '../../../test/lib/deployment/test-deployment';
-import { glob, detectBuilders } from '../src';

 jest.setTimeout(4 * 60 * 1000);

@@ -32,11 +31,6 @@ const skipFixtures: string[] = [
  '08-zero-config-middleman',
  '21-npm-workspaces',
  '23-pnpm-workspaces',
-  '27-yarn-workspaces',
-  '28-turborepo-with-yarn-workspaces',
-  '29-nested-workspaces',
-  '30-double-nested-workspaces',
-  '31-turborepo-in-package-json',
 ];

 // eslint-disable-next-line no-restricted-syntax
@@ -83,145 +77,3 @@ for (const builder of buildersToTestWith) {
    }
  }
 }
-
-it('Test `detectBuilders` and `detectRoutes`', async () => {
-  const fixture = path.join(__dirname, 'fixtures', '01-zero-config-api');
-  const pkg = await fs.readJSON(path.join(fixture, 'package.json'));
-  const fileList = await glob('**', fixture);
-  const files = Object.keys(fileList);
-
-  const probes = [
-    {
-      path: '/api/my-endpoint',
-      mustContain: 'my-endpoint',
-      status: 200,
-    },
-    {
-      path: '/api/other-endpoint',
-      mustContain: 'other-endpoint',
-      status: 200,
-    },
-    {
-      path: '/api/team/zeit',
-      mustContain: 'team/zeit',
-      status: 200,
-    },
-    {
-      path: '/api/user/myself',
-      mustContain: 'user/myself',
-      status: 200,
-    },
-    {
-      path: '/api/not-okay/',
-      status: 404,
-    },
-    {
-      path: '/api',
-      status: 404,
-    },
-    {
-      path: '/api/',
-      status: 404,
-    },
-    {
-      path: '/',
-      mustContain: 'hello from index.txt',
-    },
-  ];
-
-  const { builders, defaultRoutes } = await detectBuilders(files, pkg);
-
-  const nowConfig = { builds: builders, routes: defaultRoutes, probes };
-
-  await fs.writeFile(
-    path.join(fixture, 'now.json'),
-    JSON.stringify(nowConfig, null, 2)
-  );
-
-  const deployment = await testDeployment(
-    { builderUrl, buildUtilsUrl },
-    fixture
-  );
-  expect(deployment).toBeDefined();
-});
-
-it('Test `detectBuilders` with `index` files', async () => {
-  const fixture = path.join(__dirname, 'fixtures', '02-zero-config-api');
-  const pkg = await fs.readJSON(path.join(fixture, 'package.json'));
-  const fileList = await glob('**', fixture);
-  const files = Object.keys(fileList);
-
-  const probes = [
-    {
-      path: '/api/not-okay',
-      status: 404,
-    },
-    {
-      path: '/api',
-      mustContain: 'hello from api/index.js',
-      status: 200,
-    },
-    {
-      path: '/api/',
-      mustContain: 'hello from api/index.js',
-      status: 200,
-    },
-    {
-      path: '/api/index',
-      mustContain: 'hello from api/index.js',
-      status: 200,
-    },
-    {
-      path: '/api/index.js',
-      mustContain: 'hello from api/index.js',
-      status: 200,
-    },
-    {
-      path: '/api/date.js',
-      mustContain: 'hello from api/date.js',
-      status: 200,
-    },
-    {
-      // Someone might expect this to be `date.js`,
-      // but I doubt that there is any case were both
-      // `date/index.js` and `date.js` exists,
-      // so it is not special cased
-      path: '/api/date',
-      mustContain: 'hello from api/date/index.js',
-      status: 200,
-    },
-    {
-      path: '/api/date/',
-      mustContain: 'hello from api/date/index.js',
-      status: 200,
-    },
-    {
-      path: '/api/date/index',
-      mustContain: 'hello from api/date/index.js',
-      status: 200,
-    },
-    {
-      path: '/api/date/index.js',
-      mustContain: 'hello from api/date/index.js',
-      status: 200,
-    },
-    {
-      path: '/',
-      mustContain: 'hello from index.txt',
-    },
-  ];
-
-  const { builders, defaultRoutes } = await detectBuilders(files, pkg);
-
-  const nowConfig = { builds: builders, routes: defaultRoutes, probes };
-  await fs.writeFile(
-    path.join(fixture, 'now.json'),
-    JSON.stringify(nowConfig, null, 2)
-  );
-
-  const deployment = await testDeployment(
-    { builderUrl, buildUtilsUrl },
-    fixture
-  );
-  expect(deployment).toBeDefined();
-});
--- a/packages/build-utils/test/unit.exec-async.test.ts
+++ b/packages/build-utils/test/unit.exec-async.test.ts
@@ -0,0 +1,29 @@
+import { execAsync, NowBuildError } from '../src';
+
+it('should execute a command', async () => {
+  const { code, stdout, stderr } = await execAsync('echo', ['hello']);
+
+  expect(code).toBe(0);
+  expect(stdout).toContain('hello');
+  expect(stderr).toBe('');
+});
+
+it('should throw if the command exits with non-0 code', async () => {
+  await expect(execAsync('find', ['unknown-file'])).rejects.toBeInstanceOf(
+    NowBuildError
+  );
+});
+
+it('should return if the command exits with non-0 code and ignoreNon0Exit=true', async () => {
+  const { code, stdout, stderr } = await execAsync('find', ['unknown-file'], {
+    ignoreNon0Exit: true,
+  });
+
+  expect(code).toBe(process.platform === 'win32' ? 2 : 1);
+  expect(stdout).toBe('');
+  expect(stderr).toContain(
+    process.platform === 'win32'
+      ? 'Parameter format not correct'
+      : 'No such file or directory'
+  );
+});
--- a/packages/build-utils/test/unit.get-env-for-package-manager.test.ts
+++ b/packages/build-utils/test/unit.get-env-for-package-manager.test.ts
@@ -38,6 +38,38 @@ describe('Test `getEnvForPackageManager()`', () => {
        PATH: `/node16/bin-npm7${delimiter}foo`,
      },
    },
+    {
+      name: 'should not set npm path if corepack enabled',
+      args: {
+        cliType: 'npm',
+        nodeVersion: { major: 14, range: '14.x', runtime: 'nodejs14.x' },
+        lockfileVersion: 2,
+        env: {
+          FOO: 'bar',
+          ENABLE_EXPERIMENTAL_COREPACK: '1',
+        },
+      },
+      want: {
+        FOO: 'bar',
+        ENABLE_EXPERIMENTAL_COREPACK: '1',
+      },
+    },
+    {
+      name: 'should not prepend npm path again if already detected',
+      args: {
+        cliType: 'npm',
+        nodeVersion: { major: 14, range: '14.x', runtime: 'nodejs14.x' },
+        lockfileVersion: 2,
+        env: {
+          FOO: 'bar',
+          PATH: `/node16/bin-npm7${delimiter}foo`,
+        },
+      },
+      want: {
+        FOO: 'bar',
+        PATH: `/node16/bin-npm7${delimiter}foo`,
+      },
+    },
    {
      name: 'should not set path if node is 16 and npm 7+ is detected',
      args: {
@@ -101,6 +133,38 @@ describe('Test `getEnvForPackageManager()`', () => {
        PATH: `/pnpm7/node_modules/.bin${delimiter}foo`,
      },
    },
+    {
+      name: 'should not set pnpm path if corepack is enabled',
+      args: {
+        cliType: 'pnpm',
+        nodeVersion: { major: 16, range: '16.x', runtime: 'nodejs16.x' },
+        lockfileVersion: 5.4,
+        env: {
+          FOO: 'bar',
+          ENABLE_EXPERIMENTAL_COREPACK: '1',
+        },
+      },
+      want: {
+        FOO: 'bar',
+        ENABLE_EXPERIMENTAL_COREPACK: '1',
+      },
+    },
+    {
+      name: 'should not prepend pnpm path again if already detected',
+      args: {
+        cliType: 'pnpm',
+        nodeVersion: { major: 16, range: '16.x', runtime: 'nodejs16.x' },
+        lockfileVersion: 5.4,
+        env: {
+          FOO: 'bar',
+          PATH: `/pnpm7/node_modules/.bin${delimiter}foo`,
+        },
+      },
+      want: {
+        FOO: 'bar',
+        PATH: `/pnpm7/node_modules/.bin${delimiter}foo`,
+      },
+    },
    {
      name: 'should not set path if pnpm 6 is detected',
      args: {
--- a/packages/build-utils/test/unit.get-spawn-options.test.ts
+++ b/packages/build-utils/test/unit.get-spawn-options.test.ts
@@ -0,0 +1,111 @@
+import { delimiter } from 'path';
+import { getSpawnOptions } from '../src';
+
+describe('Test `getSpawnOptions()`', () => {
+  const origProcessEnvPath = process.env.PATH;
+
+  beforeEach(() => {
+    process.env.PATH = undefined;
+  });
+
+  afterEach(() => {
+    process.env.PATH = origProcessEnvPath;
+  });
+
+  const cases: Array<{
+    name: string;
+    args: Parameters<typeof getSpawnOptions>;
+    envPath: string | undefined;
+    want: string | undefined;
+  }> = [
+    {
+      name: 'should do nothing when isDev and node14',
+      args: [
+        { isDev: true },
+        { major: 14, range: '14.x', runtime: 'nodejs14.x' },
+      ],
+      envPath: '/foo',
+      want: '/foo',
+    },
+    {
+      name: 'should do nothing when isDev and node16',
+      args: [
+        { isDev: true },
+        { major: 16, range: '16.x', runtime: 'nodejs16.x' },
+      ],
+      envPath: '/foo',
+      want: '/foo',
+    },
+    {
+      name: 'should replace 14 with 16 when only path',
+      args: [
+        { isDev: false },
+        { major: 16, range: '16.x', runtime: 'nodejs16.x' },
+      ],
+      envPath: '/node14/bin',
+      want: '/node16/bin',
+    },
+    {
+      name: 'should replace 14 with 16 at beginning',
+      args: [
+        { isDev: false },
+        { major: 16, range: '16.x', runtime: 'nodejs16.x' },
+      ],
+      envPath: `/node14/bin${delimiter}/foo`,
+      want: `/node16/bin${delimiter}/foo`,
+    },
+    {
+      name: 'should replace 14 with 16 at end',
+      args: [
+        { isDev: false },
+        { major: 16, range: '16.x', runtime: 'nodejs16.x' },
+      ],
+      envPath: `/foo${delimiter}/node14/bin`,
+      want: `/foo${delimiter}/node16/bin`,
+    },
+    {
+      name: 'should replace 14 with 16 in middle',
+      args: [
+        { isDev: false },
+        { major: 16, range: '16.x', runtime: 'nodejs16.x' },
+      ],
+      envPath: `/foo${delimiter}/node14/bin${delimiter}/bar`,
+      want: `/foo${delimiter}/node16/bin${delimiter}/bar`,
+    },
+    {
+      name: 'should prepend 16 at beginning when nothing to replace',
+      args: [
+        { isDev: false },
+        { major: 16, range: '16.x', runtime: 'nodejs16.x' },
+      ],
+      envPath: `/foo`,
+      want: `/node16/bin${delimiter}/foo`,
+    },
+    {
+      name: 'should prepend 16 at beginning no path input',
+      args: [
+        { isDev: false },
+        { major: 16, range: '16.x', runtime: 'nodejs16.x' },
+      ],
+      envPath: '',
+      want: `/node16/bin`,
+    },
+    {
+      name: 'should replace 12 with 14 when only path',
+      args: [
+        { isDev: false },
+        { major: 14, range: '14.x', runtime: 'nodejs14.x' },
+      ],
+      envPath: '/node12/bin',
+      want: '/node14/bin',
+    },
+  ];
+
+  for (const { name, args, envPath, want } of cases) {
+    it(name, () => {
+      process.env.PATH = envPath;
+      const opts = getSpawnOptions(...args);
+      expect(opts.env?.PATH).toBe(want);
+    });
+  }
+});
--- a/packages/build-utils/test/unit.spawn-async.test.ts
+++ b/packages/build-utils/test/unit.spawn-async.test.ts
@@ -0,0 +1,21 @@
+import { spawnAsync, NowBuildError } from '../src';
+
+it('should execute a command', async () => {
+  // should resolve (it doesn't return anything, so it resolves with "undefined")
+  await expect(spawnAsync('echo', ['hello'])).resolves.toBeUndefined();
+});
+
+it('should throw if the command exits with non-0 code', async () => {
+  await expect(spawnAsync('find', ['unknown-file'])).rejects.toBeInstanceOf(
+    NowBuildError
+  );
+});
+
+it('should return if the command exits with non-0 code and ignoreNon0Exit=true', async () => {
+  // should resolve (it doesn't return anything, so it resolves with "undefined")
+  await expect(
+    spawnAsync('find', ['unknown-file'], {
+      ignoreNon0Exit: true,
+    })
+  ).resolves.toBeUndefined();
+});
--- a/packages/build-utils/test/unit.test.ts
+++ b/packages/build-utils/test/unit.test.ts
@@ -18,6 +18,8 @@ import {
  Meta,
 } from '../src';

+jest.setTimeout(7 * 1000);
+
 async function expectBuilderError(promise: Promise<any>, pattern: string) {
  let result;
  try {
--- a/packages/cli/package.json
+++ b/packages/cli/package.json
@@ -1,6 +1,6 @@
 {
  "name": "vercel",
-  "version": "25.1.1-canary.1",
+  "version": "26.0.0",
  "preferGlobal": true,
  "license": "Apache-2.0",
  "description": "The command-line interface for Vercel",
@@ -42,15 +42,15 @@
    "node": ">= 14"
  },
  "dependencies": {
-    "@vercel/build-utils": "4.1.1-canary.1",
-    "@vercel/go": "2.0.2-canary.1",
-    "@vercel/next": "3.0.2-canary.1",
-    "@vercel/node": "2.1.1-canary.1",
-    "@vercel/python": "3.0.2-canary.1",
-    "@vercel/redwood": "1.0.2-canary.1",
-    "@vercel/remix": "1.0.2-canary.1",
-    "@vercel/ruby": "1.3.10-canary.1",
-    "@vercel/static-build": "1.0.2-canary.1",
+    "@vercel/build-utils": "5.0.0",
+    "@vercel/go": "2.0.4",
+    "@vercel/next": "3.1.3",
+    "@vercel/node": "2.4.0",
+    "@vercel/python": "3.0.4",
+    "@vercel/redwood": "1.0.5",
+    "@vercel/remix": "1.0.5",
+    "@vercel/ruby": "1.3.12",
+    "@vercel/static-build": "1.0.4",
    "update-notifier": "5.1.0"
  },
  "devDependencies": {
@@ -95,8 +95,9 @@
    "@types/which": "1.3.2",
    "@types/write-json-file": "2.2.1",
    "@types/yauzl-promise": "2.1.0",
-    "@vercel/client": "12.0.2-canary.1",
-    "@vercel/frameworks": "1.0.2-canary.0",
+    "@vercel/client": "12.0.4",
+    "@vercel/frameworks": "1.0.2",
+    "@vercel/fs-detectors": "1.0.0",
    "@vercel/ncc": "0.24.0",
    "@zeit/fun": "0.11.2",
    "@zeit/source-map-support": "0.6.2",
--- a/packages/cli/src/commands/alias/rm.ts
+++ b/packages/cli/src/commands/alias/rm.ts
@@ -10,7 +10,6 @@ import confirm from '../../util/input/confirm';
 import findAliasByAliasOrId from '../../util/alias/find-alias-by-alias-or-id';

 import { Alias } from '../../types';
-import { Output } from '../../util/output';
 import { isValidName } from '../../util/is-valid-name';
 import { getCommandName } from '../../util/pkg-name';

@@ -71,7 +70,7 @@ export default async function rm(
  }

  const removeStamp = stamp();
-  if (!opts['--yes'] && !(await confirmAliasRemove(output, alias))) {
+  if (!opts['--yes'] && !(await confirmAliasRemove(client, alias))) {
    output.log('Aborted');
    return 0;
  }
@@ -85,7 +84,7 @@ export default async function rm(
  return 0;
 }

-async function confirmAliasRemove(output: Output, alias: Alias) {
+async function confirmAliasRemove(client: Client, alias: Alias) {
  const srcUrl = alias.deployment
    ? chalk.underline(alias.deployment.url)
    : null;
@@ -104,7 +103,7 @@ async function confirmAliasRemove(output: Output, alias: Alias) {
    }
  );

-  output.log(`The following alias will be removed permanently`);
-  output.print(`  ${tbl}\n`);
-  return confirm(chalk.red('Are you sure?'), false);
+  client.output.log(`The following alias will be removed permanently`);
+  client.output.print(`  ${tbl}\n`);
+  return confirm(client, chalk.red('Are you sure?'), false);
 }
--- a/packages/cli/src/commands/billing/add.js
+++ b/packages/cli/src/commands/billing/add.js
@@ -127,7 +127,7 @@ export default async function ({ creditCards, clear = false, contextName }) {
    }

    console.log(''); // New line
-    const stopSpinner = wait('Saving card');
+    const stopSpinner = wait(process.stderr, 'Saving card');

    try {
      const res = await creditCards.add({
--- a/packages/cli/src/commands/billing/index.js
+++ b/packages/cli/src/commands/billing/index.js
@@ -174,7 +174,7 @@ export default async client => {
        )} ${chalk.gray(`[${elapsed}]`)}`;
        const choices = buildInquirerChoices(cards);

-        cardId = await listInput({
+        cardId = await listInput(client, {
          message,
          choices,
          separator: true,
@@ -187,6 +187,7 @@ export default async client => {
      if (cardId) {
        const label = `Are you sure that you to set this card as the default?`;
        const confirmation = await promptBool(label, {
+          ...client,
          trailing: '\n',
        });

@@ -250,7 +251,7 @@ export default async client => {
        )} under ${chalk.bold(contextName)} ${chalk.gray(`[${elapsed}]`)}`;
        const choices = buildInquirerChoices(cards);

-        cardId = await listInput({
+        cardId = await listInput(client, {
          message,
          choices,
          separator: true,
@@ -262,7 +263,7 @@ export default async client => {
      // typed `vercel billing rm <some-id>`) is valid
      if (cardId) {
        const label = `Are you sure that you want to remove this card?`;
-        const confirmation = await promptBool(label);
+        const confirmation = await promptBool(label, client);
        if (!confirmation) {
          console.log('Aborted');
          break;
--- a/packages/cli/src/commands/bisect/index.ts
+++ b/packages/cli/src/commands/bisect/index.ts
@@ -14,8 +14,8 @@ import logo from '../../util/output/logo';
 import getArgs from '../../util/get-args';
 import Client from '../../util/client';
 import { getPkgName } from '../../util/pkg-name';
-import { Output } from '../../util/output';
 import { Deployment, PaginationOptions } from '../../types';
+import { normalizeURL } from '../../util/bisect/normalize-url';

 interface DeploymentV6
  extends Pick<
@@ -85,10 +85,10 @@ export default async function main(client: Client): Promise<number> {

  let bad =
    argv['--bad'] ||
-    (await prompt(output, `Specify a URL where the bug occurs:`));
+    (await prompt(client, `Specify a URL where the bug occurs:`));
  let good =
    argv['--good'] ||
-    (await prompt(output, `Specify a URL where the bug does not occur:`));
+    (await prompt(client, `Specify a URL where the bug does not occur:`));
  let subpath = argv['--path'] || '';
  let run = argv['--run'] || '';
  const openEnabled = argv['--open'] || false;
@@ -97,9 +97,7 @@ export default async function main(client: Client): Promise<number> {
    run = resolve(run);
  }

-  if (!bad.startsWith('https://')) {
-    bad = `https://${bad}`;
-  }
+  bad = normalizeURL(bad);
  let parsed = parse(bad);
  if (!parsed.hostname) {
    output.error('Invalid input: no hostname provided');
@@ -120,9 +118,7 @@ export default async function main(client: Client): Promise<number> {

  const badDeploymentPromise = getDeployment(client, bad).catch(err => err);

-  if (!good.startsWith('https://')) {
-    good = `https://${good}`;
-  }
+  good = normalizeURL(good);
  parsed = parse(good);
  if (!parsed.hostname) {
    output.error('Invalid input: no hostname provided');
@@ -146,7 +142,7 @@ export default async function main(client: Client): Promise<number> {

  if (!subpath) {
    subpath = await prompt(
-      output,
+      client,
      `Specify the URL subpath where the bug occurs:`
    );
  }
@@ -394,10 +390,10 @@ function getCommit(deployment: DeploymentV6) {
  return { sha, message };
 }

-async function prompt(output: Output, message: string): Promise<string> {
+async function prompt(client: Client, message: string): Promise<string> {
  // eslint-disable-next-line no-constant-condition
  while (true) {
-    const { val } = await inquirer.prompt({
+    const { val } = await client.prompt({
      type: 'input',
      name: 'val',
      message,
@@ -405,7 +401,7 @@ async function prompt(output: Output, message: string): Promise<string> {
    if (val) {
      return val;
    } else {
-      output.error('A value must be specified');
+      client.output.error('A value must be specified');
    }
  }
 }
--- a/packages/cli/src/commands/build.ts
+++ b/packages/cli/src/commands/build.ts
@@ -1,9 +1,8 @@
 import fs from 'fs-extra';
 import chalk from 'chalk';
 import dotenv from 'dotenv';
-import { join, normalize, relative } from 'path';
+import { join, normalize, relative, resolve } from 'path';
 import {
-  detectBuilders,
  normalizePath,
  Files,
  FileFsRef,
@@ -17,6 +16,7 @@ import {
  BuildResultV3,
  NowBuildError,
 } from '@vercel/build-utils';
+import { detectBuilders } from '@vercel/fs-detectors';
 import minimatch from 'minimatch';
 import {
  appendRoutesToPhase,
@@ -65,6 +65,7 @@ const help = () => {
    'DIR'
  )}    Path to the global ${'`.vercel`'} directory
      --cwd [path]                   The current working directory
+      --output [path]                Directory where built assets should be written to
      --prod                         Build a production deployment
      -d, --debug                    Debug mode [off]
      -y, --yes                      Skip the confirmation prompt
@@ -101,6 +102,7 @@ export default async function main(client: Client): Promise<number> {
  // Parse CLI args
  const argv = getArgs(client.argv.slice(2), {
    '--cwd': String,
+    '--output': String,
    '--prod': Boolean,
    '--yes': Boolean,
  });
@@ -138,6 +140,7 @@ export default async function main(client: Client): Promise<number> {
      }

      confirmed = await confirm(
+        client,
        `No Project Settings found locally. Run ${cli.getCommandName(
          'pull'
        )} for retrieving them?`,
@@ -280,7 +283,9 @@ export default async function main(client: Client): Promise<number> {
  }

  // Delete output directory from potential previous build
-  const outputDir = join(cwd, OUTPUT_DIR);
+  const outputDir = argv['--output']
+    ? resolve(argv['--output'])
+    : join(cwd, OUTPUT_DIR);
  await fs.remove(outputDir);

  const buildStamp = stamp();
@@ -297,6 +302,7 @@ export default async function main(client: Client): Promise<number> {
      {
        '//': 'This file was generated by the `vercel build` command. It is not part of the Build Output API.',
        target,
+        argv: process.argv,
        builds: builds.map(build => {
          const builderWithPkg = buildersWithPkgs.get(build.use);
          if (!builderWithPkg) {
@@ -305,6 +311,7 @@ export default async function main(client: Client): Promise<number> {
          const { builder, pkg: builderPkg } = builderWithPkg;
          return {
            require: builderPkg.name,
+            requirePath: builderWithPkg.path,
            apiVersion: builder.version,
            ...build,
          };
@@ -463,11 +470,12 @@ export default async function main(client: Client): Promise<number> {
  };
  await fs.writeJSON(join(outputDir, 'config.json'), config, { spaces: 2 });

+  const relOutputDir = relative(cwd, outputDir);
  output.print(
    `${prependEmoji(
-      `Build Completed in ${chalk.bold(OUTPUT_DIR)} ${chalk.gray(
-        buildStamp()
-      )}`,
+      `Build Completed in ${chalk.bold(
+        relOutputDir.startsWith('..') ? outputDir : relOutputDir
+      )} ${chalk.gray(buildStamp())}`,
      emoji('success')
    )}\n`
  );
--- a/packages/cli/src/commands/deploy/index.ts
+++ b/packages/cli/src/commands/deploy/index.ts
@@ -160,12 +160,12 @@ export default async (client: Client) => {
    }
  }

-  const { log, debug, error, prettyError, isTTY } = output;
+  const { log, debug, error, prettyError } = output;

-  const quiet = !isTTY;
+  const quiet = !client.stdout.isTTY;

  // check paths
-  const pathValidation = await validatePaths(output, paths);
+  const pathValidation = await validatePaths(client, paths);

  if (!pathValidation.valid) {
    return pathValidation.exitCode;
@@ -243,6 +243,7 @@ export default async (client: Client) => {
    const shouldStartSetup =
      autoConfirm ||
      (await confirm(
+        client,
        `Set up and deploy ${chalk.cyan(`“${toHumanPath(path)}”`)}?`,
        true
      ));
@@ -287,7 +288,7 @@ export default async (client: Client) => {

    if (typeof projectOrNewProjectName === 'string') {
      newProjectName = projectOrNewProjectName;
-      rootDirectory = await inputRootDirectory(path, output, autoConfirm);
+      rootDirectory = await inputRootDirectory(client, path, autoConfirm);
    } else {
      project = projectOrNewProjectName;
      rootDirectory = project.rootDirectory;
@@ -521,7 +522,7 @@ export default async (client: Client) => {
      }

      const settings = await editProjectSettings(
-        output,
+        client,
        projectSettings,
        framework,
        false,
--- a/packages/cli/src/commands/dev/dev.ts
+++ b/packages/cli/src/commands/dev/dev.ts
@@ -110,9 +110,11 @@ export default async function dev(
  // v3 Build Output because it will incorrectly be detected by
  // @vercel/static-build in BuildOutputV3.getBuildOutputDirectory()
  if (!devCommand) {
-    output.log(`Removing ${OUTPUT_DIR}`);
    const outputDir = join(cwd, OUTPUT_DIR);
-    await fs.remove(outputDir);
+    if (await fs.pathExists(outputDir)) {
+      output.log(`Removing ${OUTPUT_DIR}`);
+      await fs.remove(outputDir);
+    }
  }

  const devServer = new DevServer(cwd, {
--- a/packages/cli/src/commands/dns/add.ts
+++ b/packages/cli/src/commands/dns/add.ts
@@ -46,7 +46,7 @@ export default async function add(

  const addStamp = stamp();
  const { domain, data: argData } = parsedParams;
-  const data = await getDNSData(output, argData);
+  const data = await getDNSData(client, argData);
  if (!data) {
    output.log(`Aborted`);
    return 1;
--- a/packages/cli/src/commands/domains/buy.ts
+++ b/packages/cli/src/commands/domains/buy.ts
@@ -87,7 +87,8 @@ export default async function buy(
    !(await promptBool(
      `Buy now for ${chalk.bold(`$${price}`)} (${`${period}yr${
        period > 1 ? 's' : ''
-      }`})?`
+      }`})?`,
+      client
    ))
  ) {
    return 0;
@@ -99,7 +100,7 @@ export default async function buy(
      : `Auto renew every ${renewalPrice.period} years for ${chalk.bold(
          `$${price}`
        )}?`,
-    { defaultValue: true }
+    { ...client, defaultValue: true }
  );

  let buyResult;
--- a/packages/cli/src/commands/domains/move.ts
+++ b/packages/cli/src/commands/domains/move.ts
@@ -77,7 +77,8 @@ export default async function move(
      !(await promptBool(
        `Are you sure you want to move ${param(domainName)} to ${param(
          destination
-        )}?`
+        )}?`,
+        client
      ))
    ) {
      output.log('Aborted');
@@ -95,7 +96,8 @@ export default async function move(
      );
      if (
        !(await promptBool(
-          `Are you sure you want to move ${param(domainName)}?`
+          `Are you sure you want to move ${param(domainName)}?`,
+          client
        ))
      ) {
        output.log('Aborted');
--- a/packages/cli/src/commands/domains/rm.ts
+++ b/packages/cli/src/commands/domains/rm.ts
@@ -92,7 +92,10 @@ export default async function rm(
  const skipConfirmation = opts['--yes'] || false;
  if (
    !skipConfirmation &&
-    !(await promptBool(`Are you sure you want to remove ${param(domainName)}?`))
+    !(await promptBool(
+      `Are you sure you want to remove ${param(domainName)}?`,
+      client
+    ))
  ) {
    output.log('Aborted');
    return 0;
@@ -230,7 +233,7 @@ async function removeDomain(

    if (
      !skipConfirmation &&
-      !(await promptBool(`Remove conflicts associated with domain?`))
+      !(await promptBool(`Remove conflicts associated with domain?`, client))
    ) {
      output.log('Aborted');
      return 0;
--- a/packages/cli/src/commands/domains/transfer-in.ts
+++ b/packages/cli/src/commands/domains/transfer-in.ts
@@ -81,7 +81,8 @@ export default async function transferIn(
  const shouldTransfer = await promptBool(
    transferPolicy === 'no-change'
      ? `Transfer now for ${chalk.bold(`$${price}`)}?`
-      : `Transfer now with 1yr renewal for ${chalk.bold(`$${price}`)}?`
+      : `Transfer now with 1yr renewal for ${chalk.bold(`$${price}`)}?`,
+    client
  );
  if (!shouldTransfer) {
    return 0;
--- a/packages/cli/src/commands/env/add.ts
+++ b/packages/cli/src/commands/env/add.ts
@@ -31,7 +31,7 @@ export default async function add(
  // improve the way we show inquirer prompts
  require('../../util/input/patch-inquirer');

-  const stdInput = await readStandardInput();
+  const stdInput = await readStandardInput(client.stdin);
  let [envName, envTargetArg, envGitBranch] = args;

  if (args.length > 3) {
--- a/packages/cli/src/commands/env/pull.ts
+++ b/packages/cli/src/commands/env/pull.ts
@@ -74,6 +74,7 @@ export default async function pull(
    exists &&
    !skipConfirmation &&
    !(await confirm(
+      client,
      `Found existing file ${param(filename)}. Do you want to overwrite?`,
      false
    ))
--- a/packages/cli/src/commands/env/rm.ts
+++ b/packages/cli/src/commands/env/rm.ts
@@ -104,6 +104,7 @@ export default async function rm(
  if (
    !skipConfirmation &&
    !(await confirm(
+      client,
      `Removing Environment Variable ${param(env.key)} from ${formatEnvTarget(
        env
      )} in Project ${chalk.bold(project.name)}. Are you sure?`,
--- a/packages/cli/src/commands/init/init.ts
+++ b/packages/cli/src/commands/init/init.ts
@@ -46,7 +46,11 @@ export default async function init(
  const exampleList = examples.filter(x => x.visible).map(x => x.name);

  if (!name) {
-    const chosen = await chooseFromDropdown('Select example:', exampleList);
+    const chosen = await chooseFromDropdown(
+      client,
+      'Select example:',
+      exampleList
+    );

    if (!chosen) {
      output.log('Aborted');
@@ -65,7 +69,7 @@ export default async function init(
    return extractExample(client, name, dir, force, 'v1');
  }

-  const found = await guess(exampleList, name);
+  const found = await guess(client, exampleList, name);

  if (typeof found === 'string') {
    return extractExample(client, found, dir, force);
@@ -90,14 +94,18 @@ async function fetchExampleList(client: Client) {
 /**
 * Prompt user for choosing which example to init
 */
-async function chooseFromDropdown(message: string, exampleList: string[]) {
+async function chooseFromDropdown(
+  client: Client,
+  message: string,
+  exampleList: string[]
+) {
  const choices = exampleList.map(name => ({
    name,
    value: name,
    short: name,
  }));

-  return listInput({
+  return listInput(client, {
    message,
    choices,
  });
@@ -194,7 +202,7 @@ function prepareFolder(cwd: string, folder: string, force?: boolean) {
 /**
 * Guess which example user try to init
 */
-async function guess(exampleList: string[], name: string) {
+async function guess(client: Client, exampleList: string[], name: string) {
  const GuessError = new Error(
    `No example found for ${chalk.bold(name)}, run ${getCommandName(
      `init`
@@ -208,7 +216,7 @@ async function guess(exampleList: string[], name: string) {
  const found = didYouMean(name, exampleList, 0.7);

  if (typeof found === 'string') {
-    if (await promptBool(`Did you mean ${chalk.bold(found)}?`)) {
+    if (await promptBool(`Did you mean ${chalk.bold(found)}?`, client)) {
      return found;
    }
  } else {
--- a/packages/cli/src/commands/teams/switch.ts
+++ b/packages/cli/src/commands/teams/switch.ts
@@ -83,7 +83,7 @@ export default async function main(client: Client, desiredSlug?: string) {
    ];

    output.stopSpinner();
-    desiredSlug = await listInput({
+    desiredSlug = await listInput(client, {
      message: 'Switch to:',
      choices,
      eraseFinalAnswer: true,
--- a/packages/cli/src/commands/whoami.ts
+++ b/packages/cli/src/commands/whoami.ts
@@ -54,12 +54,12 @@ export default async (client: Client): Promise<number> => {
    throw err;
  }

-  if (output.isTTY) {
+  if (client.stdout.isTTY) {
    output.log(contextName);
  } else {
    // If stdout is not a TTY, then only print the username
    // to support piping the output to another file / exe
-    output.print(`${contextName}\n`, { w: process.stdout });
+    client.stdout.write(`${contextName}\n`);
  }

  return 0;
--- a/packages/cli/src/index.ts
+++ b/packages/cli/src/index.ts
@@ -23,7 +23,7 @@ import * as Sentry from '@sentry/node';
 import hp from './util/humanize-path';
 import commands from './commands';
 import pkg from './util/pkg';
-import createOutput from './util/output';
+import { Output } from './util/output';
 import cmd from './util/output/cmd';
 import info from './util/output/info';
 import error from './util/output/error';
@@ -109,7 +109,7 @@ const main = async () => {
  }

  const isDebugging = argv['--debug'];
-  const output = createOutput({ debug: isDebugging });
+  const output = new Output(process.stderr, { debug: isDebugging });

  debug = output.debug;

@@ -387,6 +387,9 @@ const main = async () => {
  // Shared API `Client` instance for all sub-commands to utilize
  client = new Client({
    apiUrl,
+    stdin: process.stdin,
+    stdout: process.stdout,
+    stderr: output.stream,
    output,
    config,
    authConfig,
@@ -796,7 +799,5 @@ process.on('uncaughtException', handleUnexpected);
 main()
  .then(exitCode => {
    process.exitCode = exitCode;
-    // @ts-ignore - "nowExit" is a non-standard event name
-    process.emit('nowExit');
  })
  .catch(handleUnexpected);
--- a/packages/cli/src/types.ts
+++ b/packages/cli/src/types.ts
@@ -1,3 +1,5 @@
+import type { Readable, Writable } from 'stream';
+
 export type ProjectSettings = import('@vercel/build-utils').ProjectSettings;

 export type Primitive =
@@ -442,3 +444,19 @@ export interface BuildOutput {
    layers?: string[];
  } | null;
 }
+
+export interface ReadableTTY extends Readable {
+  isTTY?: boolean;
+  isRaw?: boolean;
+  setRawMode?: (mode: boolean) => void;
+}
+
+export interface WritableTTY extends Writable {
+  isTTY?: boolean;
+}
+
+export interface Stdio {
+  stdin: ReadableTTY;
+  stdout: WritableTTY;
+  stderr: WritableTTY;
+}
--- a/packages/cli/src/util/bisect/normalize-url.ts
+++ b/packages/cli/src/util/bisect/normalize-url.ts
@@ -0,0 +1,7 @@
+function hasScheme(url: string): Boolean {
+  return url.startsWith('http://') || url.startsWith('https://');
+}
+
+export function normalizeURL(url: string): string {
+  return hasScheme(url) ? url : `https://${url}`;
+}
--- a/packages/cli/src/util/build/write-build-result.ts
+++ b/packages/cli/src/util/build/write-build-result.ts
@@ -385,8 +385,14 @@ export async function* findDirs(
  }
  for (const path of paths) {
    const abs = join(dir, path);
-    const s = await fs.stat(abs);
-    if (s.isDirectory()) {
+    let stat: fs.Stats;
+    try {
+      stat = await fs.lstat(abs);
+    } catch (err: any) {
+      if (err.code === 'ENOENT') continue;
+      throw err;
+    }
+    if (stat.isDirectory()) {
      if (path === name) {
        yield relative(root, abs);
      } else {
--- a/packages/cli/src/util/client.ts
+++ b/packages/cli/src/util/client.ts
@@ -1,3 +1,5 @@
+import { bold } from 'chalk';
+import inquirer from 'inquirer';
 import { EventEmitter } from 'events';
 import { URLSearchParams } from 'url';
 import { parse as parseUrl } from 'url';
@@ -11,10 +13,16 @@ import printIndications from './print-indications';
 import reauthenticate from './login/reauthenticate';
 import { SAMLError } from './login/types';
 import { writeToAuthConfigFile } from './config/files';
-import { AuthConfig, GlobalConfig, JSONObject } from '../types';
+import type {
+  AuthConfig,
+  GlobalConfig,
+  JSONObject,
+  Stdio,
+  ReadableTTY,
+  WritableTTY,
+} from '../types';
 import { sharedPromise } from './promise';
 import { APIError } from './errors-ts';
-import { bold } from 'chalk';

 const isSAMLError = (v: any): v is SAMLError => {
  return v && v.saml;
@@ -28,7 +36,7 @@ export interface FetchOptions extends Omit<RequestInit, 'body'> {
  accountId?: string;
 }

-export interface ClientOptions {
+export interface ClientOptions extends Stdio {
  argv: string[];
  apiUrl: string;
  authConfig: AuthConfig;
@@ -41,13 +49,17 @@ export const isJSONObject = (v: any): v is JSONObject => {
  return v && typeof v == 'object' && v.constructor === Object;
 };

-export default class Client extends EventEmitter {
+export default class Client extends EventEmitter implements Stdio {
  argv: string[];
  apiUrl: string;
  authConfig: AuthConfig;
+  stdin: ReadableTTY;
+  stdout: WritableTTY;
+  stderr: WritableTTY;
  output: Output;
  config: GlobalConfig;
  localConfig?: VercelConfig;
+  prompt!: inquirer.PromptModule;
  private requestIdCounter: number;

  constructor(opts: ClientOptions) {
@@ -55,10 +67,14 @@ export default class Client extends EventEmitter {
    this.argv = opts.argv;
    this.apiUrl = opts.apiUrl;
    this.authConfig = opts.authConfig;
+    this.stdin = opts.stdin;
+    this.stdout = opts.stdout;
+    this.stderr = opts.stderr;
    this.output = opts.output;
    this.config = opts.config;
    this.localConfig = opts.localConfig;
    this.requestIdCounter = 1;
+    this._createPromptModule();
  }

  retry<T>(fn: RetryFunction<T>, { retries = 3, maxTimeout = Infinity } = {}) {
@@ -124,7 +140,7 @@ export default class Client extends EventEmitter {
    return this.retry(async bail => {
      const res = await this._fetch(url, opts);

-      printIndications(res);
+      printIndications(this, res);

      if (!res.ok) {
        const error = await responseError(res);
@@ -180,4 +196,11 @@ export default class Client extends EventEmitter {
  _onRetry = (error: Error) => {
    this.output.debug(`Retrying: ${error}\n${error.stack}`);
  };
+
+  _createPromptModule() {
+    this.prompt = inquirer.createPromptModule({
+      input: this.stdin as NodeJS.ReadStream,
+      output: this.stderr as NodeJS.WriteStream,
+    });
+  }
 }
--- a/packages/cli/src/util/dev/builder.ts
+++ b/packages/cli/src/util/dev/builder.ts
@@ -13,8 +13,8 @@ import {
  Lambda,
  FileBlob,
  FileFsRef,
-  isOfficialRuntime,
 } from '@vercel/build-utils';
+import { isOfficialRuntime } from '@vercel/fs-detectors';
 import plural from 'pluralize';
 import minimatch from 'minimatch';

@@ -425,10 +425,6 @@ export async function getBuildMatches(
      src = extensionless;
    }

-    // We need to escape brackets since `glob` will
-    // try to find a group otherwise
-    src = src.replace(/(\[|\])/g, '[$1]');
-
    const files = fileList
      .filter(name => name === src || minimatch(name, src, { dot: true }))
      .map(name => join(cwd, name));
--- a/packages/cli/src/util/dev/headers.ts
+++ b/packages/cli/src/util/dev/headers.ts
@@ -0,0 +1,18 @@
+import { Headers } from 'node-fetch';
+import { IncomingHttpHeaders, OutgoingHttpHeaders } from 'http';
+
+export function nodeHeadersToFetchHeaders(
+  nodeHeaders: IncomingHttpHeaders | OutgoingHttpHeaders
+): Headers {
+  const headers = new Headers();
+  for (const [name, value] of Object.entries(nodeHeaders)) {
+    if (Array.isArray(value)) {
+      for (const val of value) {
+        headers.append(name, val);
+      }
+    } else if (typeof value !== 'undefined') {
+      headers.set(name, String(value));
+    }
+  }
+  return headers;
+}
--- a/packages/cli/src/util/dev/server.ts
+++ b/packages/cli/src/util/dev/server.ts
@@ -1,12 +1,13 @@
+import ms from 'ms';
 import url, { URL } from 'url';
 import http from 'http';
 import fs from 'fs-extra';
 import chalk from 'chalk';
+import fetch from 'node-fetch';
 import plural from 'pluralize';
 import rawBody from 'raw-body';
 import listen from 'async-listen';
 import minimatch from 'minimatch';
-import ms from 'ms';
 import httpProxy from 'http-proxy';
 import { randomBytes } from 'crypto';
 import serveHandler from 'serve-handler';
@@ -16,11 +17,11 @@ import path, { isAbsolute, basename, dirname, extname, join } from 'path';
 import once from '@tootallnate/once';
 import directoryTemplate from 'serve-handler/src/directory';
 import getPort from 'get-port';
-import { ChildProcess } from 'child_process';
 import isPortReachable from 'is-port-reachable';
 import deepEqual from 'fast-deep-equal';
 import which from 'which';
 import npa from 'npm-package-arg';
+import type { ChildProcess } from 'child_process';

 import { getVercelIgnore, fileNameSymbol } from '@vercel/client';
 import {
@@ -35,12 +36,14 @@ import {
  StartDevServerResult,
  FileFsRef,
  PackageJson,
+  spawnCommand,
+} from '@vercel/build-utils';
+import {
  detectBuilders,
  detectApiDirectory,
  detectApiExtensions,
-  spawnCommand,
  isOfficialRuntime,
-} from '@vercel/build-utils';
+} from '@vercel/fs-detectors';
 import frameworkList from '@vercel/frameworks';

 import cmd from '../output/cmd';
@@ -90,6 +93,7 @@ import {
 import { ProjectEnvVariable, ProjectSettings } from '../../types';
 import exposeSystemEnvs from './expose-system-envs';
 import { treeKill } from '../tree-kill';
+import { nodeHeadersToFetchHeaders } from './headers';

 const frontendRuntimeSet = new Set(
  frameworkList.map(f => f.useRuntime?.use || '@vercel/static-build')
@@ -327,6 +331,8 @@ export default class DevServer {
  ): Promise<void> {
    const name = relative(this.cwd, fsPath);
    try {
+      await this.getVercelConfig();
+
      this.files[name] = await FileFsRef.fromFsPath({ fsPath });
      const extensionless = this.getExtensionlessFile(name);
      if (extensionless) {
@@ -593,7 +599,7 @@ export default class DevServer {
        await this.exit();
      }

-      if (warnings && warnings.length > 0) {
+      if (warnings?.length > 0) {
        warnings.forEach(warning =>
          this.output.warn(warning.message, null, warning.link, warning.action)
        );
@@ -1106,6 +1112,7 @@ export default class DevServer {
        view = errorTemplate({
          http_status_code: statusCode,
          http_status_description,
+          error_code,
          request_id: requestId,
        });
      }
@@ -1337,32 +1344,6 @@ export default class DevServer {
    return false;
  };

-  /*
-  runDevMiddleware = async (
-    req: http.IncomingMessage,
-    res: http.ServerResponse
-  ) => {
-    const { devMiddlewarePlugins } = await loadCliPlugins(
-      this.cwd,
-      this.output
-    );
-    try {
-      for (let plugin of devMiddlewarePlugins) {
-        const result = await plugin.plugin.runDevMiddleware(req, res, this.cwd);
-        if (result.finished) {
-          return result;
-        }
-      }
-      return { finished: false };
-    } catch (e) {
-      return {
-        finished: true,
-        error: e,
-      };
-    }
-  };
-  */
-
  /**
   * Serve project directory as a v2 deployment.
   */
@@ -1429,13 +1410,143 @@ export default class DevServer {
    let statusCode: number | undefined;
    let prevUrl = req.url;
    let prevHeaders: HttpHeadersConfig = {};
+    let middlewarePid: number | undefined;

-    /*
-    const middlewareResult = await this.runDevMiddleware(req, res);
+    // Run the middleware file, if present, and apply any
+    // mutations to the incoming request based on the
+    // result of the middleware invocation.
+    const middleware = [...this.buildMatches.values()].find(
+      m => m.config?.middleware === true
+    );
+    if (middleware) {
+      let startMiddlewareResult: StartDevServerResult | undefined;
+      // TODO: can we add some caching to prevent (re-)starting
+      // the middleware server for every HTTP request?
+      const { envConfigs, files, devCacheDir, cwd: workPath } = this;
+      try {
+        startMiddlewareResult =
+          await middleware.builderWithPkg.builder.startDevServer?.({
+            files,
+            entrypoint: middleware.entrypoint,
+            workPath,
+            repoRootPath: this.cwd,
+            config: middleware.config || {},
+            meta: {
+              isDev: true,
+              devCacheDir,
+              requestUrl: req.url,
+              env: { ...envConfigs.runEnv },
+              buildEnv: { ...envConfigs.buildEnv },
+            },
+          });

-    if (middlewareResult) {
-      if (middlewareResult.error) {
-        this.sendError(
+        if (startMiddlewareResult) {
+          const { port, pid } = startMiddlewareResult;
+          middlewarePid = pid;
+          this.devServerPids.add(pid);
+
+          const middlewareReqHeaders = nodeHeadersToFetchHeaders(req.headers);
+
+          // Add the Vercel platform proxy request headers
+          const proxyHeaders = this.getProxyHeaders(req, requestId, true);
+          for (const [name, value] of nodeHeadersToFetchHeaders(proxyHeaders)) {
+            middlewareReqHeaders.set(name, value);
+          }
+
+          const middlewareRes = await fetch(
+            `http://127.0.0.1:${port}${parsed.path}`,
+            {
+              headers: middlewareReqHeaders,
+              method: req.method,
+              redirect: 'manual',
+            }
+          );
+
+          if (middlewareRes.status === 500) {
+            await this.sendError(
+              req,
+              res,
+              requestId,
+              'EDGE_FUNCTION_INVOCATION_FAILED',
+              500
+            );
+            return;
+          }
+
+          // Apply status code from middleware invocation,
+          // for i.e. redirects or a custom 404 page
+          res.statusCode = middlewareRes.status;
+
+          let rewritePath = '';
+          let contentType = '';
+          let shouldContinue = false;
+          const skipMiddlewareHeaders = new Set([
+            'date',
+            'connection',
+            'content-length',
+            'transfer-encoding',
+          ]);
+          for (const [name, value] of middlewareRes.headers) {
+            if (name === 'x-middleware-next') {
+              shouldContinue = value === '1';
+            } else if (name === 'x-middleware-rewrite') {
+              rewritePath = value;
+              shouldContinue = true;
+            } else if (name === 'content-type') {
+              contentType = value;
+            } else if (!skipMiddlewareHeaders.has(name)) {
+              // Any other kind of response header should be included
+              // on both the incoming HTTP request (for when proxying
+              // to another function) and the outgoing HTTP response.
+              res.setHeader(name, value);
+              req.headers[name] = value;
+            }
+          }
+
+          if (!shouldContinue) {
+            const middlewareBody = await middlewareRes.buffer();
+            this.setResponseHeaders(res, requestId);
+            if (middlewareBody.length > 0) {
+              res.setHeader('content-length', middlewareBody.length);
+              if (contentType) {
+                res.setHeader('content-type', contentType);
+              }
+              res.end(middlewareBody);
+            } else {
+              res.end();
+            }
+            return;
+          }
+
+          if (rewritePath) {
+            // TODO: add validation?
+            debug(`Detected rewrite path from middleware: "${rewritePath}"`);
+            prevUrl = rewritePath;
+
+            // Retain orginal pathname, but override query parameters from the rewrite
+            const beforeRewriteUrl = req.url || '/';
+            const rewriteUrlParsed = url.parse(beforeRewriteUrl, true);
+            delete rewriteUrlParsed.search;
+            rewriteUrlParsed.query = url.parse(rewritePath, true).query;
+            req.url = url.format(rewriteUrlParsed);
+            debug(
+              `Rewrote incoming HTTP URL from "${beforeRewriteUrl}" to "${req.url}"`
+            );
+          }
+        }
+      } catch (err) {
+        // `startDevServer()` threw an error. Most likely this means the dev
+        // server process exited before sending the port information message
+        // (missing dependency at runtime, for example).
+        if (err.code === 'ENOENT') {
+          err.message = `Command not found: ${chalk.cyan(
+            err.path,
+            ...err.spawnargs
+          )}\nPlease ensure that ${cmd(err.path)} is properly installed`;
+          err.link = 'https://vercel.link/command-not-found';
+        }
+
+        await this.sendError(
          req,
          res,
          requestId,
@@ -1443,24 +1554,12 @@ export default class DevServer {
          500
        );
        return;
-      }
-      if (middlewareResult.finished) {
-        return;
-      }
-
-      if (middlewareResult.pathname) {
-        const origUrl = url.parse(req.url || '/', true);
-        origUrl.pathname = middlewareResult.pathname;
-        prevUrl = url.format(origUrl);
-      }
-      if (middlewareResult.query && prevUrl) {
-        const origUrl = url.parse(req.url || '/', true);
-        delete origUrl.search;
-        Object.assign(origUrl.query, middlewareResult.query);
-        prevUrl = url.format(origUrl);
+      } finally {
+        if (middlewarePid) {
+          this.killBuilderDevServer(middlewarePid);
+        }
      }
    }
-    */

    for (const phase of phases) {
      statusCode = undefined;
@@ -1740,7 +1839,10 @@ export default class DevServer {
            isDev: true,
            requestPath,
            devCacheDir,
-            env: { ...envConfigs.runEnv },
+            env: {
+              ...envConfigs.runEnv,
+              VERCEL_BUILDER_DEBUG: this.output.debugEnabled ? '1' : undefined,
+            },
            buildEnv: { ...envConfigs.buildEnv },
          },
        });
@@ -2185,13 +2287,7 @@ function proxyPass(
        `Failed to complete request to ${req.url}: ${error}`
      );
      if (!res.headersSent) {
-        devServer.sendError(
-          req,
-          res,
-          requestId,
-          'NO_RESPONSE_FROM_FUNCTION',
-          502
-        );
+        devServer.sendError(req, res, requestId, 'FUNCTION_INVOCATION_FAILED');
      }
    }
  );
@@ -2269,11 +2365,12 @@ async function findBuildMatch(
      if (!isIndex(match.src)) {
        return match;
      } else {
-        // if isIndex === true and ends in .html, we're done. Otherwise, keep searching
-        bestIndexMatch = match;
+        // If isIndex === true and ends in `.html`, we're done.
+        // Otherwise, keep searching.
        if (extname(match.src) === '.html') {
-          return bestIndexMatch;
+          return match;
        }
+        bestIndexMatch = match;
      }
    }
  }
@@ -2295,6 +2392,13 @@ async function shouldServe(
    config,
    builderWithPkg: { builder },
  } = match;
+
+  // "middleware" file is not served as a regular asset,
+  // instead it gets invoked as part of the routing logic.
+  if (config?.middleware === true) {
+    return false;
+  }
+
  const cleanSrc = src.endsWith('.html') ? src.slice(0, -5) : src;
  const trimmedPath = requestPath.endsWith('/')
    ? requestPath.slice(0, -1)
--- a/packages/cli/src/util/dns/get-dns-data.ts
+++ b/packages/cli/src/util/dns/get-dns-data.ts
@@ -2,26 +2,29 @@ import chalk from 'chalk';
 import { DNSRecordData } from '../../types';
 import textInput from '../input/text';
 import promptBool from '../input/prompt-bool';
-import { Output } from '../output';
+import Client from '../client';

 const RECORD_TYPES = ['A', 'AAAA', 'ALIAS', 'CAA', 'CNAME', 'MX', 'SRV', 'TXT'];

 export default async function getDNSData(
-  output: Output,
+  client: Client,
  data: null | DNSRecordData
 ): Promise<DNSRecordData | null> {
  if (data) {
    return data;
  }
+  const { output } = client;

  try {
    // first ask for type, branch from there
    const possibleTypes = new Set(RECORD_TYPES);
-    const type = (await textInput({
-      label: `- Record type (${RECORD_TYPES.join(', ')}): `,
-      validateValue: (v: string) =>
-        Boolean(v && possibleTypes.has(v.trim().toUpperCase()))
-    }))
+    const type = (
+      await textInput({
+        label: `- Record type (${RECORD_TYPES.join(', ')}): `,
+        validateValue: (v: string) =>
+          Boolean(v && possibleTypes.has(v.trim().toUpperCase())),
+      })
+    )
      .trim()
      .toUpperCase();

@@ -39,7 +42,7 @@ export default async function getDNSData(
          target
        )}.`
      );
-      return (await verifyData())
+      return (await verifyData(client))
        ? {
            name,
            type,
@@ -47,8 +50,8 @@ export default async function getDNSData(
              priority,
              weight,
              port,
-              target
-            }
+              target,
+            },
          }
        : null;
    }
@@ -61,23 +64,23 @@ export default async function getDNSData(
          `${mxPriority}`
        )} ${chalk.cyan(value)}`
      );
-      return (await verifyData())
+      return (await verifyData(client))
        ? {
            name,
            type,
            value,
-            mxPriority
+            mxPriority,
          }
        : null;
    }

    const value = await getTrimmedString(`- ${type} value: `);
    output.log(`${chalk.cyan(name)} ${chalk.bold(type)} ${chalk.cyan(value)}`);
-    return (await verifyData())
+    return (await verifyData(client))
      ? {
          name,
          type,
-          value
+          value,
        }
      : null;
  } catch (error) {
@@ -85,13 +88,13 @@ export default async function getDNSData(
  }
 }

-async function verifyData() {
-  return promptBool('Is this correct?');
+async function verifyData(client: Client) {
+  return promptBool('Is this correct?', client);
 }

 async function getRecordName(type: string) {
  const input = await textInput({
-    label: `- ${type} name: `
+    label: `- ${type} name: `,
  });
  return input === '@' ? '' : input;
 }
@@ -100,14 +103,14 @@ async function getNumber(label: string) {
  return Number(
    await textInput({
      label,
-      validateValue: v => Boolean(v && Number(v))
+      validateValue: v => Boolean(v && Number(v)),
    })
  );
 }
 async function getTrimmedString(label: string) {
  const res = await textInput({
    label,
-    validateValue: v => Boolean(v && v.trim().length > 0)
+    validateValue: v => Boolean(v && v.trim().length > 0),
  });
  return res.trim();
 }
--- a/packages/cli/src/util/domains/purchase-domain-if-available.ts
+++ b/packages/cli/src/util/domains/purchase-domain-if-available.ts
@@ -54,7 +54,8 @@ export default async function purchaseDomainIfAvailable(
      !(await promptBool(
        `Buy ${chalk.underline(domain)} for ${chalk.bold(
          `$${price}`
-        )} (${plural('yr', period, true)})?`
+        )} (${plural('yr', period, true)})?`,
+        client
      ))
    ) {
      output.print(eraseLines(1));
--- a/packages/cli/src/util/get-files.ts
+++ b/packages/cli/src/util/get-files.ts
@@ -1,5 +1,5 @@
-import { resolve } from 'path';
 import fs from 'fs-extra';
+import { resolve } from 'path';
 import { getVercelIgnore } from '@vercel/client';
 import uniqueStrings from './unique-strings';
 import { Output } from './output/create-output';
--- a/packages/cli/src/util/index.ts
+++ b/packages/cli/src/util/index.ts
@@ -530,7 +530,7 @@ export default class Now extends EventEmitter {
      `${opts.method || 'GET'} ${this._apiUrl}${_url} ${opts.body || ''}`,
      fetch(`${this._apiUrl}${_url}`, { ...opts, body })
    );
-    printIndications(res);
+    printIndications(this._client, res);
    return res;
  }

--- a/packages/cli/src/util/input/confirm.ts
+++ b/packages/cli/src/util/input/confirm.ts
@@ -1,12 +1,13 @@
-import inquirer from 'inquirer';
+import Client from '../client';

 export default async function confirm(
+  client: Client,
  message: string,
  preferred: boolean
 ): Promise<boolean> {
  require('./patch-inquirer');

-  const answers = await inquirer.prompt({
+  const answers = await client.prompt({
    type: 'confirm',
    name: 'value',
    message,
--- a/packages/cli/src/util/input/edit-project-settings.ts
+++ b/packages/cli/src/util/input/edit-project-settings.ts
@@ -1,8 +1,8 @@
 import inquirer from 'inquirer';
 import confirm from './confirm';
 import chalk from 'chalk';
-import { Output } from '../output';
 import frameworkList, { Framework } from '@vercel/frameworks';
+import Client from '../client';
 import { isSettingValue } from '../is-setting-value';
 import { ProjectSettings } from '../../types';

@@ -22,12 +22,14 @@ const settingKeys = Object.keys(settingMap).sort() as unknown as readonly [
 export type PartialProjectSettings = Pick<ProjectSettings, ConfigKeys>;

 export default async function editProjectSettings(
-  output: Output,
+  client: Client,
  projectSettings: PartialProjectSettings | null,
  framework: Framework | null,
  autoConfirm: boolean,
  localConfigurationOverrides: PartialProjectSettings | null
 ): Promise<ProjectSettings> {
+  const { output } = client;
+
  // Create initial settings object defaulting everything to `null` and assigning what may exist in `projectSettings`
  const settings: ProjectSettings = Object.assign(
    {
@@ -118,7 +120,7 @@ export default async function editProjectSettings(
  // Prompt the user if they want to modify any settings not defined by local configuration.
  if (
    autoConfirm ||
-    !(await confirm('Want to modify these settings?', false))
+    !(await confirm(client, 'Want to modify these settings?', false))
  ) {
    return settings;
  }
--- a/packages/cli/src/util/input/input-project.ts
+++ b/packages/cli/src/util/input/input-project.ts
@@ -1,5 +1,4 @@
 import Client from '../client';
-import inquirer from 'inquirer';
 import confirm from './confirm';
 import getProjectByIdOrName from '../projects/get-project-by-id-or-name';
 import chalk from 'chalk';
@@ -47,11 +46,16 @@ export default async function inputProject(

  if (!detectedProject) {
    // did not auto-detect a project to link
-    shouldLinkProject = await confirm(`Link to existing project?`, false);
+    shouldLinkProject = await confirm(
+      client,
+      `Link to existing project?`,
+      false
+    );
  } else {
    // auto-detected a project to link
    if (
      await confirm(
+        client,
        `Found project ${chalk.cyan(
          `“${org.slug}/${detectedProject.name}”`
        )}. Link to it?`,
@@ -63,6 +67,7 @@ export default async function inputProject(

    // user doesn't want to link the auto-detected project
    shouldLinkProject = await confirm(
+      client,
      `Link to different existing project?`,
      true
    );
@@ -73,7 +78,7 @@ export default async function inputProject(
    let project: Project | ProjectNotFound | null = null;

    while (!project || project instanceof ProjectNotFound) {
-      const answers = await inquirer.prompt({
+      const answers = await client.prompt({
        type: 'input',
        name: 'existingProjectName',
        message: `What’s the name of your existing project?`,
@@ -104,7 +109,7 @@ export default async function inputProject(
  let newProjectName: string | null = null;

  while (!newProjectName) {
-    const answers = await inquirer.prompt({
+    const answers = await client.prompt({
      type: 'input',
      name: 'newProjectName',
      message: `What’s your project’s name?`,
--- a/packages/cli/src/util/input/input-root-directory.ts
+++ b/packages/cli/src/util/input/input-root-directory.ts
@@ -1,12 +1,11 @@
 import path from 'path';
 import chalk from 'chalk';
-import inquirer from 'inquirer';
-import { Output } from '../output';
 import { validateRootDirectory } from '../validate-paths';
+import Client from '../client';

 export async function inputRootDirectory(
+  client: Client,
  cwd: string,
-  output: Output,
  autoConfirm = false
 ) {
  if (autoConfirm) {
@@ -15,7 +14,7 @@ export async function inputRootDirectory(

  // eslint-disable-next-line no-constant-condition
  while (true) {
-    const { rootDirectory } = await inquirer.prompt({
+    const { rootDirectory } = await client.prompt({
      type: 'input',
      name: 'rootDirectory',
      message: `In which directory is your code located?`,
@@ -38,7 +37,7 @@ export async function inputRootDirectory(

    if (
      (await validateRootDirectory(
-        output,
+        client.output,
        cwd,
        fullPath,
        'Please choose a different one.'
--- a/packages/cli/src/util/input/list.ts
+++ b/packages/cli/src/util/input/list.ts
@@ -1,5 +1,6 @@
 import inquirer from 'inquirer';
 import stripAnsi from 'strip-ansi';
+import Client from '../client';
 import eraseLines from '../output/erase-lines';

 interface ListEntry {
@@ -35,21 +36,24 @@ function getLength(input: string): number {
  return biggestLength;
 }

-export default async function list({
-  message = 'the question',
-  // eslint-disable-line no-unused-vars
-  choices: _choices = [
-    {
-      name: 'something\ndescription\ndetails\netc',
-      value: 'something unique',
-      short: 'generally the first line of `name`',
-    },
-  ],
-  pageSize = 15, // Show 15 lines without scrolling (~4 credit cards)
-  separator = false, // Puts a blank separator between each choice
-  abort = 'end', // Whether the `abort` option will be at the `start` or the `end`,
-  eraseFinalAnswer = false, // If true, the line with the final answer that inquirer prints will be erased before returning
-}: ListOptions): Promise<string> {
+export default async function list(
+  client: Client,
+  {
+    message = 'the question',
+    // eslint-disable-line no-unused-vars
+    choices: _choices = [
+      {
+        name: 'something\ndescription\ndetails\netc',
+        value: 'something unique',
+        short: 'generally the first line of `name`',
+      },
+    ],
+    pageSize = 15, // Show 15 lines without scrolling (~4 credit cards)
+    separator = false, // Puts a blank separator between each choice
+    abort = 'end', // Whether the `abort` option will be at the `start` or the `end`,
+    eraseFinalAnswer = false, // If true, the line with the final answer that inquirer prints will be erased before returning
+  }: ListOptions
+): Promise<string> {
  require('./patch-inquirer-legacy');

  let biggestLength = 0;
@@ -106,7 +110,7 @@ export default async function list({
    choices.push(abortSeparator, _abort);
  }

-  const answer = await inquirer.prompt({
+  const answer = await client.prompt({
    name: 'value',
    type: 'list',
    default: selected,
--- a/packages/cli/src/util/input/prompt-bool.ts
+++ b/packages/cli/src/util/input/prompt-bool.ts
@@ -1,25 +1,26 @@
 import chalk from 'chalk';
+import type { ReadableTTY, WritableTTY } from '../../types';

 type Options = {
  abortSequences?: Set<string>;
  defaultValue?: boolean;
  noChar?: string;
  resolveChars?: Set<string>;
-  stdin?: NodeJS.ReadStream;
-  stdout?: NodeJS.WriteStream;
+  stdin: ReadableTTY;
+  stdout: WritableTTY;
  trailing?: string;
  yesChar?: string;
 };

-export default async function promptBool(label: string, options: Options = {}) {
+export default async function promptBool(label: string, options: Options) {
  const {
+    stdin,
+    stdout,
    defaultValue = false,
    abortSequences = new Set(['\u0003']),
    resolveChars = new Set(['\r']),
    yesChar = 'y',
    noChar = 'n',
-    stdin = process.stdin,
-    stdout = process.stdout,
    trailing = '',
  } = options;

--- a/packages/cli/src/util/input/read-standard-input.ts
+++ b/packages/cli/src/util/input/read-standard-input.ts
@@ -1,13 +1,17 @@
-export default async function readStandardInput(): Promise<string> {
+import type { ReadableTTY } from '../../types';
+
+export default async function readStandardInput(
+  stdin: ReadableTTY
+): Promise<string> {
  return new Promise<string>(resolve => {
    setTimeout(() => resolve(''), 500);

-    if (process.stdin.isTTY) {
+    if (stdin.isTTY) {
      // found tty so we know there is nothing piped to stdin
      resolve('');
    } else {
-      process.stdin.setEncoding('utf8');
-      process.stdin.once('data', resolve);
+      stdin.setEncoding('utf8');
+      stdin.once('data', resolve);
    }
  });
 }
--- a/packages/cli/src/util/link/setup-and-link.ts
+++ b/packages/cli/src/util/link/setup-and-link.ts
@@ -56,7 +56,7 @@ export default async function setupAndLink(
    return { status: 'error', exitCode: 1, reason: 'PATH_IS_FILE' };
  }
  const link = await getLinkedProject(client, path);
-  const isTTY = process.stdout.isTTY;
+  const isTTY = client.stdin.isTTY;
  const quiet = !isTTY;
  let rootDirectory: string | null = null;
  let sourceFilesOutsideRootDirectory = true;
@@ -80,6 +80,7 @@ export default async function setupAndLink(
  const shouldStartSetup =
    autoConfirm ||
    (await confirm(
+      client,
      `${setupMsg} ${chalk.cyan(`“${toHumanPath(path)}”`)}?`,
      true
    ));
@@ -120,7 +121,7 @@ export default async function setupAndLink(

  if (typeof projectOrNewProjectName === 'string') {
    newProjectName = projectOrNewProjectName;
-    rootDirectory = await inputRootDirectory(path, output, autoConfirm);
+    rootDirectory = await inputRootDirectory(client, path, autoConfirm);
  } else {
    const project = projectOrNewProjectName;

@@ -224,7 +225,7 @@ export default async function setupAndLink(
      const { projectSettings, framework } = deployment;

      settings = await editProjectSettings(
-        output,
+        client,
        projectSettings,
        framework,
        autoConfirm,
--- a/packages/cli/src/util/login/oauth.ts
+++ b/packages/cli/src/util/login/oauth.ts
@@ -176,7 +176,7 @@ async function getVerificationTokenOutOfBand(client: Client, url: URL) {
  output.log(
    `After login is complete, enter the verification code printed in your browser.`
  );
-  const verificationToken = await readInput('Verification code:');
+  const verificationToken = await readInput(client, 'Verification code:');
  output.print(eraseLines(6));

  // If the pasted token begins with "saml_", then the `ssoUserId` was returned.
--- a/packages/cli/src/util/login/prompt.ts
+++ b/packages/cli/src/util/login/prompt.ts
@@ -1,4 +1,3 @@
-import inquirer from 'inquirer';
 import Client from '../client';
 import error from '../output/error';
 import listInput from '../input/list';
@@ -32,7 +31,7 @@ export default async function prompt(
    choices.pop();
  }

-  const choice = await listInput({
+  const choice = await listInput(client, {
    message: 'Log in to Vercel',
    choices,
  });
@@ -44,22 +43,26 @@ export default async function prompt(
  } else if (choice === 'bitbucket') {
    result = await doBitbucketLogin(client, outOfBand, ssoUserId);
  } else if (choice === 'email') {
-    const email = await readInput('Enter your email address:');
+    const email = await readInput(client, 'Enter your email address:');
    result = await doEmailLogin(client, email, ssoUserId);
  } else if (choice === 'saml') {
-    const slug = error?.teamId || (await readInput('Enter your Team slug:'));
+    const slug =
+      error?.teamId || (await readInput(client, 'Enter your Team slug:'));
    result = await doSamlLogin(client, slug, outOfBand, ssoUserId);
  }

  return result;
 }

-export async function readInput(message: string): Promise<string> {
+export async function readInput(
+  client: Client,
+  message: string
+): Promise<string> {
  let input;

  while (!input) {
    try {
-      const { val } = await inquirer.prompt({
+      const { val } = await client.prompt({
        type: 'input',
        name: 'val',
        message,
--- a/packages/cli/src/util/login/reauthenticate.ts
+++ b/packages/cli/src/util/login/reauthenticate.ts
@@ -14,7 +14,7 @@ export default async function reauthenticate(
    client.output.log(
      `You must re-authenticate with SAML to use ${bold(error.scope)} scope.`
    );
-    if (await confirm(`Log in with SAML?`, true)) {
+    if (await confirm(client, `Log in with SAML?`, true)) {
      return doSamlLogin(client, error.teamId);
    }
  } else {
--- a/packages/cli/src/util/output/create-output.ts
+++ b/packages/cli/src/util/output/create-output.ts
@@ -1,41 +1,39 @@
 import chalk from 'chalk';
 import renderLink from './link';
 import wait, { StopSpinner } from './wait';
-import { Writable } from 'stream';
+import type { WritableTTY } from '../../types';

 export interface OutputOptions {
  debug?: boolean;
 }

-export interface PrintOptions {
-  w?: Writable;
-}
-
-export interface LogOptions extends PrintOptions {
+export interface LogOptions {
  color?: typeof chalk;
 }

 export class Output {
+  stream: WritableTTY;
  debugEnabled: boolean;
  private spinnerMessage: string;
  private _spinner: StopSpinner | null;
-  isTTY: boolean;

-  constructor({ debug: debugEnabled = false }: OutputOptions = {}) {
+  constructor(
+    stream: WritableTTY,
+    { debug: debugEnabled = false }: OutputOptions = {}
+  ) {
+    this.stream = stream;
    this.debugEnabled = debugEnabled;
    this.spinnerMessage = '';
    this._spinner = null;
-    this.isTTY = process.stdout.isTTY || false;
  }

  isDebugEnabled = () => {
    return this.debugEnabled;
  };

-  print = (str: string, { w }: PrintOptions = { w: process.stderr }) => {
+  print = (str: string) => {
    this.stopSpinner();
-    const stream: Writable = w || process.stderr;
-    stream.write(str);
+    this.stream.write(str);
  };

  log = (str: string, color = chalk.grey) => {
@@ -111,11 +109,17 @@ export class Output {
      this.debug(`Spinner invoked (${message}) with a ${delay}ms delay`);
      return;
    }
-    if (this.isTTY) {
+    if (this.stream.isTTY) {
      if (this._spinner) {
        this._spinner.text = message;
      } else {
-        this._spinner = wait(message, delay);
+        this._spinner = wait(
+          {
+            text: message,
+            stream: this.stream,
+          },
+          delay
+        );
      }
    } else {
      this.print(`${message}\n`);
@@ -157,7 +161,3 @@ export class Output {
    return promise;
  };
 }
-
-export default function createOutput(opts?: OutputOptions) {
-  return new Output(opts);
-}
--- a/packages/cli/src/util/output/index.ts
+++ b/packages/cli/src/util/output/index.ts
@@ -1,2 +1,2 @@
-export { default, Output } from './create-output';
+export { Output } from './create-output';
 export { StopSpinner } from './wait';
--- a/packages/cli/src/util/output/wait.ts
+++ b/packages/cli/src/util/output/wait.ts
@@ -8,14 +8,19 @@ export interface StopSpinner {
 }

 export default function wait(
-  msg: string,
-  delay: number = 300,
-  _ora = ora
+  opts: ora.Options,
+  delay: number = 300
 ): StopSpinner {
-  let spinner: ReturnType<typeof _ora> | null = null;
+  let text = opts.text;
+  let spinner: ora.Ora | null = null;
+
+  if (typeof text !== 'string') {
+    throw new Error(`"text" is required for Ora spinner`);
+  }

  const timeout = setTimeout(() => {
-    spinner = _ora(chalk.gray(msg));
+    spinner = ora(opts);
+    spinner.text = chalk.gray(text);
    spinner.color = 'gray';
    spinner.start();
  }, delay);
@@ -29,23 +34,21 @@ export default function wait(
    }
  };

-  stop.text = msg;
+  stop.text = text;

  // Allow `text` property to update the text while the spinner is in action
  Object.defineProperty(stop, 'text', {
    get() {
-      return msg;
+      return text;
    },

    set(v: string) {
-      msg = v;
+      text = v;
      if (spinner) {
        spinner.text = chalk.gray(v);
      }
    },
  });

-  // @ts-ignore
-  process.once('nowExit', stop);
  return stop;
 }
--- a/packages/cli/src/util/pkg.ts
+++ b/packages/cli/src/util/pkg.ts
@@ -1,6 +1,14 @@
-import _pkg from '../../package.json';
+import fs from 'fs';
+import { join } from 'path';
 import { PackageJson } from '@vercel/build-utils';

-const pkg: PackageJson & typeof _pkg = _pkg;
+let rootDir = __dirname;
+while (!fs.existsSync(join(rootDir, 'package.json'))) {
+  rootDir = join(rootDir, '..');
+}

+const pkgPath = join(rootDir, 'package.json');
+const pkg: PackageJson & typeof import('../../package.json') = JSON.parse(
+  fs.readFileSync(pkgPath, 'utf8')
+);
 export default pkg;
--- a/packages/cli/src/util/print-indications.ts
+++ b/packages/cli/src/util/print-indications.ts
@@ -1,11 +1,10 @@
 import chalk from 'chalk';
 import { Response } from 'node-fetch';
-import { emoji, EmojiLabel, prependEmoji } from './emoji';
-import createOutput from './output';
+import Client from './client';
 import linkStyle from './output/link';
+import { emoji, EmojiLabel, prependEmoji } from './emoji';

-export default function printIndications(res: Response) {
-  const _output = createOutput();
+export default function printIndications(client: Client, res: Response) {
  const indications = new Set(['warning', 'notice', 'tip']);
  const regex = /^x-(?:vercel|now)-(warning|notice|tip)-(.*)$/;

@@ -25,7 +24,7 @@ export default function printIndications(res: Response) {
            chalk.dim(`${action || 'Learn More'}: ${linkStyle(link)}`) +
            newline;
        }
-        _output.print(message + finalLink);
+        client.output.print(message + finalLink);
      }
    }
  }
--- a/packages/cli/src/util/validate-paths.ts
+++ b/packages/cli/src/util/validate-paths.ts
@@ -5,6 +5,7 @@ import chalk from 'chalk';
 import { homedir } from 'os';
 import confirm from './input/confirm';
 import toHumanPath from './humanize-path';
+import Client from './client';

 const stat = promisify(lstatRaw);

@@ -51,9 +52,11 @@ export async function validateRootDirectory(
 }

 export default async function validatePaths(
-  output: Output,
+  client: Client,
  paths: string[]
 ): Promise<{ valid: true; path: string } | { valid: false; exitCode: number }> {
+  const { output } = client;
+
  // can't deploy more than 1 path
  if (paths.length > 1) {
    output.print(`${chalk.red('Error!')} Can't deploy more than one path.\n`);
@@ -85,6 +88,7 @@ export default async function validatePaths(
  // ask confirmation if the directory is home
  if (path === homedir()) {
    const shouldDeployHomeDirectory = await confirm(
+      client,
      `You are deploying your home directory. Do you want to continue?`,
      false
    );
--- a/packages/cli/test/dev/fixtures/edge-function-error/api/edge-error-config.js
+++ b/packages/cli/test/dev/fixtures/edge-function-error/api/edge-error-config.js
@@ -0,0 +1,7 @@
+export const config = {
+  runtime: 'invalid-runtime-value',
+};
+
+export default async function edge(request, event) {
+  throw new Error('intentional runtime error');
+}
--- a/packages/cli/test/dev/fixtures/edge-function-error/api/edge-error-no-handler.js
+++ b/packages/cli/test/dev/fixtures/edge-function-error/api/edge-error-no-handler.js
@@ -0,0 +1,8 @@
+export const config = {
+  runtime: 'experimental-edge',
+};
+
+export async function notTheDefaultExport(request, event) {
+  // this will never be run
+  return new Response('some response body');
+}
--- a/packages/cli/test/dev/fixtures/edge-function-error/api/edge-error-runtime.js
+++ b/packages/cli/test/dev/fixtures/edge-function-error/api/edge-error-runtime.js
@@ -0,0 +1,7 @@
+export const config = {
+  runtime: 'experimental-edge',
+};
+
+export default async function edge(request, event) {
+  throw new Error('intentional runtime error');
+}
--- a/packages/cli/test/dev/fixtures/edge-function-error/api/edge-error-startup.js
+++ b/packages/cli/test/dev/fixtures/edge-function-error/api/edge-error-startup.js
@@ -0,0 +1,10 @@
+export const config = {
+  runtime: 'experimental-edge',
+};
+
+export default async function edge(request, event) {
+  // this should never be executed
+  return new Response('some response body');
+}
+
+throw new Error('intentional startup error');
--- a/packages/cli/test/dev/fixtures/edge-function-error/api/edge-error-syntax.js
+++ b/packages/cli/test/dev/fixtures/edge-function-error/api/edge-error-syntax.js
@@ -0,0 +1,9 @@
+export const config = {
+  runtime: 'experimental-edge'
+}
+
+export default async function edge(request, event) {
+  return new Response('some response body');
+
+// intentional missing closing bracket to produce syntax error
+// }
--- a/Show More
+++ b/Show More