[static-build] Add support for Build Output v3 detection (#7669)

Adds detection logic for a framework / build script outputting Build Output v3
format to the filesystem. In this case, `static-build` will simply stop processing
after the Build Command since deserialization happens in the build-container side
of things (this is different compared to the v1 output which gets handled in this
Builder. The reason for that is because the v3 output matches what `vc build`
outputs vs. v1 which is a different format).

packages/build-utils/src/types.ts

@@ -356,7 +356,29 @@ export interface Images {
   formats?: ImageFormat[];
 }
 
-export interface BuildResultV2 {
+/**
+ * If a Builder ends up creating filesystem outputs conforming to
+ * the Build Output API, then the Builder should return this type.
+ */
+export interface BuildResultBuildOutput {
+  /**
+   * Version number of the Build Output API that was created.
+   * Currently only `3` is a valid value.
+   * @example 3
+   */
+  buildOutputVersion: 3;
+  /**
+   * Filesystem path to the Build Output directory.
+   * @example "/path/to/.vercel/output"
+   */
+  buildOutputPath: string;
+}
+
+/**
+ * When a Builder implements `version: 2`, the `build()` function is expected
+ * to return this type.
+ */
+export interface BuildResultV2Typical {
   // TODO: use proper `Route` type from `routing-utils` (perhaps move types to a common package)
   routes?: any[];
   images?: Images;
@@ -369,6 +391,8 @@ export interface BuildResultV2 {
   }>;
 }
 
+export type BuildResultV2 = BuildResultV2Typical | BuildResultBuildOutput;
+
 export interface BuildResultV3 {
   output: Lambda;
 }

packages/static-build/package.json

@@ -14,13 +14,24 @@
   },
   "scripts": {
     "build": "node build",
-    "test-unit": "jest --env node --verbose --runInBand --bail test/unit.test.js",
+    "test-unit": "jest --env node --verbose --bail test/build.test.ts test/prepare-cache.test.ts",
     "test-integration-once": "jest --env node --verbose --runInBand --bail test/integration.test.js",
     "prepublishOnly": "node build"
   },
+  "jest": {
+    "preset": "ts-jest/presets/default",
+    "testEnvironment": "node",
+    "globals": {
+      "ts-jest": {
+        "diagnostics": true,
+        "isolatedModules": true
+      }
+    }
+  },
   "devDependencies": {
     "@types/aws-lambda": "8.10.64",
     "@types/cross-spawn": "6.0.0",
+    "@types/jest": "27.4.1",
     "@types/ms": "0.7.31",
     "@types/node-fetch": "2.5.4",
     "@types/promise-timeout": "1.3.0",

packages/static-build/src/index.ts

@@ -4,7 +4,7 @@ import fetch from 'node-fetch';
 import getPort from 'get-port';
 import isPortReachable from 'is-port-reachable';
 import frameworks, { Framework } from '@vercel/frameworks';
-import { ChildProcess, SpawnOptions } from 'child_process';
+import type { ChildProcess, SpawnOptions } from 'child_process';
 import { existsSync, readFileSync, statSync, readdirSync } from 'fs';
 import { cpus } from 'os';
 import {
@@ -30,14 +30,12 @@ import {
   NowBuildError,
   scanParentDirs,
 } from '@vercel/build-utils';
-import { Route, Source } from '@vercel/routing-utils';
+import type { Route, Source } from '@vercel/routing-utils';
-import {
+import * as BuildOutputV1 from './utils/build-output-v1';
-  readBuildOutputDirectory,
+import * as BuildOutputV3 from './utils/build-output-v3';
-  readBuildOutputConfig,
-} from './utils/read-build-output';
 import * as GatsbyUtils from './utils/gatsby';
 import * as NuxtUtils from './utils/nuxt';
-import { ImagesConfig, BuildConfig } from './utils/_shared';
+import type { ImagesConfig, BuildConfig } from './utils/_shared';
 
 const sleep = (n: number) => new Promise(resolve => setTimeout(resolve, n));
 
@@ -284,11 +282,8 @@ export const build: BuildV2 = async ({
   );
 
   const pkg = getPkg(entrypoint, workPath);
-
   const devScript = pkg ? getScriptName(pkg, 'dev', config) : null;
-
   const framework = getFramework(config, pkg);
-
   const devCommand = getCommand('dev', pkg, config, framework);
   const buildCommand = getCommand('build', pkg, config, framework);
   const installCommand = getCommand('install', pkg, config, framework);
@@ -637,6 +632,30 @@ export const build: BuildV2 = async ({
 
       const outputDirPrefix = path.join(workPath, path.dirname(entrypoint));
 
+      // If the Build Command or Framework output files according to the
+      // Build Output v3 API, then stop processing here in `static-build`
+      // since the output is already in its final form.
+      const buildOutputPath = await BuildOutputV3.getBuildOutputDirectory(
+        outputDirPrefix
+      );
+
+      if (buildOutputPath) {
+        // Ensure that `vercel build` is being used for this Deployment
+        if (!meta.cliVersion) {
+          let buildCommandName: string;
+          if (buildCommand) buildCommandName = `"${buildCommand}"`;
+          else if (framework) buildCommandName = framework.name;
+          else buildCommandName = 'the "build" script';
+          throw new Error(
+            `Detected Build Output v3 from ${buildCommandName}, but this Deployment is not using \`vercel build\`.\nPlease set the \`ENABLE_VC_BUILD=1\` environment variable.`
+          );
+        }
+        return {
+          buildOutputVersion: 3,
+          buildOutputPath,
+        };
+      }
+
       if (framework) {
         const outputDirName = config.outputDirectory
           ? config.outputDirectory
@@ -656,7 +675,7 @@ export const build: BuildV2 = async ({
         }
       }
 
-      const extraOutputs = await readBuildOutputDirectory({
+      const extraOutputs = await BuildOutputV1.readBuildOutputDirectory({
         workPath,
         nodeVersion,
       });
@@ -750,7 +769,7 @@ export const prepareCache: PrepareCache = async ({
   const cacheFiles: Files = {};
 
   // File System API v1 cache files
-  const buildConfig = await readBuildOutputConfig<BuildConfig>({
+  const buildConfig = await BuildOutputV1.readBuildOutputConfig<BuildConfig>({
     workPath,
     configFileName: 'build.json',
   });

packages/static-build/src/utils/build-output-v3.ts

@@ -0,0 +1,23 @@
+import { join } from 'path';
+import { promises as fs } from 'fs';
+
+const BUILD_OUTPUT_DIR = '.vercel/output';
+
+/**
+ * Returns the path to the Build Output v3 directory when the
+ * `config.json` file was created by the framework / build script,
+ * or `undefined` if the framework did not create the v3 output.
+ */
+export async function getBuildOutputDirectory(
+  path: string
+): Promise<string | undefined> {
+  try {
+    const outputDir = join(path, BUILD_OUTPUT_DIR);
+    const configPath = join(outputDir, 'config.json');
+    await fs.stat(configPath);
+    return outputDir;
+  } catch (err: any) {
+    if (err.code !== 'ENOENT') throw err;
+  }
+  return undefined;
+}

packages/static-build/src/utils/gatsby.ts

@@ -30,9 +30,7 @@ export async function injectVercelAnalyticsPlugin(dir: string) {
     `Injecting Gatsby.js analytics plugin "${gatsbyPluginPackageName}" to \`${gatsbyConfigPath}\``
   );
 
-  const pkgJson: DeepWriteable<PackageJson> = (await readPackageJson(
+  const pkgJson = (await readPackageJson(dir)) as DeepWriteable<PackageJson>;
-    dir
-  )) as DeepWriteable<PackageJson>;
   if (!pkgJson.dependencies) {
     pkgJson.dependencies = {};
   }

packages/static-build/test/build-fixtures/09-build-output-v3/build.js

@@ -0,0 +1,7 @@
+const fs = require('fs');
+fs.mkdirSync('.vercel/output/static', { recursive: true });
+fs.writeFileSync('.vercel/output/config.json', '{}');
+fs.writeFileSync(
+  '.vercel/output/static/index.html',
+  '<h1>Build Output API</h1>'
+);

packages/static-build/test/build-fixtures/09-build-output-v3/package.json

@@ -0,0 +1,7 @@
+{
+  "name": "09-build-output-v3",
+  "private": true,
+  "scripts": {
+    "build": "node build.js"
+  }
+}

packages/static-build/test/build.test.ts

@@ -0,0 +1,54 @@
+import path from 'path';
+import { build } from '../src';
+
+describe('build()', () => {
+  it('should detect Builder Output v3', async () => {
+    const workPath = path.join(
+      __dirname,
+      'build-fixtures',
+      '09-build-output-v3'
+    );
+    const buildResult = await build({
+      files: {},
+      entrypoint: 'package.json',
+      workPath,
+      config: {},
+      meta: {
+        skipDownload: true,
+        cliVersion: '0.0.0',
+      },
+    });
+    if ('output' in buildResult) {
+      throw new Error('Unexpected `output` in build result');
+    }
+    expect(buildResult.buildOutputVersion).toEqual(3);
+    expect(buildResult.buildOutputPath).toEqual(
+      path.join(workPath, '.vercel/output')
+    );
+  });
+
+  it('should throw an Error with Builder Output v3 without `vercel build`', async () => {
+    let err;
+    const workPath = path.join(
+      __dirname,
+      'build-fixtures',
+      '09-build-output-v3'
+    );
+    try {
+      await build({
+        files: {},
+        entrypoint: 'package.json',
+        workPath,
+        config: {},
+        meta: {
+          skipDownload: true,
+        },
+      });
+    } catch (_err: any) {
+      err = _err;
+    }
+    expect(err.message).toEqual(
+      `Detected Build Output v3 from the "build" script, but this Deployment is not using \`vercel build\`.\nPlease set the \`ENABLE_VC_BUILD=1\` environment variable.`
+    );
+  });
+});

packages/static-build/test/prepare-cache.test.ts

@@ -1,12 +1,13 @@
-const { prepareCache } = require('../dist');
+import path from 'path';
-const path = require('path');
+import { prepareCache } from '../src';
 
-describe('prepareCache', () => {
+describe('prepareCache()', () => {
   test('should cache node_modules and .shadow-cljs', async () => {
     const files = await prepareCache({
       config: { zeroConfig: true },
       workPath: path.resolve(__dirname, './cache-fixtures/default'),
       entrypoint: 'index.js',
+      files: {},
     });
 
     expect(files['node_modules/file']).toBeDefined();
@@ -19,6 +20,7 @@ describe('prepareCache', () => {
       config: { zeroConfig: true },
       workPath: path.resolve(__dirname, './cache-fixtures/withCacheConfig'),
       entrypoint: 'index.js',
+      files: {},
     });
 
     expect(files['node_modules/file']).toBeUndefined();
@@ -32,6 +34,7 @@ describe('prepareCache', () => {
       config: { zeroConfig: true },
       workPath: path.resolve(__dirname, './cache-fixtures/gatsby'),
       entrypoint: 'package.json',
+      files: {},
     });
 
     expect(files['node_modules/file2']).toBeDefined();
@@ -45,6 +48,7 @@ describe('prepareCache', () => {
       config: { zeroConfig: true, framework: 'jekyll' },
       workPath: path.resolve(__dirname, './cache-fixtures/jekyll'),
       entrypoint: 'Gemfile',
+      files: {},
     });
 
     expect(files['vendor/bundle/b1']).toBeDefined();

packages/static-build/test/tsconfig.json

@@ -0,0 +1,4 @@
+{
+  "extends": "../tsconfig.json",
+  "include": ["*.test.ts"]
+}

packages/static-build/tsconfig.json

@@ -11,7 +11,7 @@
     "noUnusedLocals": true,
     "noUnusedParameters": true,
     "outDir": "dist",
-    "types": ["node"],
+    "types": ["node", "jest"],
     "strict": true,
     "target": "es2018"
   },

yarn.lock

@@ -2180,6 +2180,14 @@
     jest-diff "^27.0.0"
     pretty-format "^27.0.0"
 
+"@types/jest@27.4.1":
+  version "27.4.1"
+  resolved "https://registry.yarnpkg.com/@types/jest/-/jest-27.4.1.tgz#185cbe2926eaaf9662d340cc02e548ce9e11ab6d"
+  integrity sha512-23iPJADSmicDVrWk+HT58LMJtzLAnB2AgIzplQuq/bSrGaxCrlvRFjGbXmamnnk/mAmCdLStiGqggu28ocUyiw==
+  dependencies:
+    jest-matcher-utils "^27.0.0"
+    pretty-format "^27.0.0"
+
 "@types/js-yaml@3.12.1":
   version "3.12.1"
   resolved "https://registry.yarnpkg.com/@types/js-yaml/-/js-yaml-3.12.1.tgz#5c6f4a1eabca84792fbd916f0cb40847f123c656"
@@ -4677,6 +4685,11 @@ diff-sequences@^27.0.6:
   resolved "https://registry.yarnpkg.com/diff-sequences/-/diff-sequences-27.0.6.tgz#3305cb2e55a033924054695cc66019fd7f8e5723"
   integrity sha512-ag6wfpBFyNXZ0p8pcuIDS//D8H062ZQJ3fzYxjpmeKjnz8W4pekL3AI8VohmyZmsWW2PWaHgjsmqR6L13101VQ==
 
+diff-sequences@^27.5.1:
+  version "27.5.1"
+  resolved "https://registry.yarnpkg.com/diff-sequences/-/diff-sequences-27.5.1.tgz#eaecc0d327fd68c8d9672a1e64ab8dccb2ef5327"
+  integrity sha512-k1gCAXAsNgLwEL+Y8Wvl+M6oEFj5bgazfZULpS5CneoPPXRaCCW7dm+q21Ky2VEE5X+VeRDBVg1Pcvvsr4TtNQ==
+
 diff@^4.0.1:
   version "4.0.2"
   resolved "https://registry.yarnpkg.com/diff/-/diff-4.0.2.tgz#60f3aecb89d5fae520c11aa19efc2bb982aade7d"
@@ -7160,6 +7173,16 @@ jest-diff@^27.3.1:
     jest-get-type "^27.3.1"
     pretty-format "^27.3.1"
 
+jest-diff@^27.5.1:
+  version "27.5.1"
+  resolved "https://registry.yarnpkg.com/jest-diff/-/jest-diff-27.5.1.tgz#a07f5011ac9e6643cf8a95a462b7b1ecf6680def"
+  integrity sha512-m0NvkX55LDt9T4mctTEgnZk3fmEg3NRYutvMPWM/0iPnkFj2wIeF45O1718cMSOFO1vINkqmxqD8vE37uTEbqw==
+  dependencies:
+    chalk "^4.0.0"
+    diff-sequences "^27.5.1"
+    jest-get-type "^27.5.1"
+    pretty-format "^27.5.1"
+
 jest-docblock@^27.0.6:
   version "27.0.6"
   resolved "https://registry.yarnpkg.com/jest-docblock/-/jest-docblock-27.0.6.tgz#cc78266acf7fe693ca462cbbda0ea4e639e4e5f3"
@@ -7213,6 +7236,11 @@ jest-get-type@^27.3.1:
   resolved "https://registry.yarnpkg.com/jest-get-type/-/jest-get-type-27.3.1.tgz#a8a2b0a12b50169773099eee60a0e6dd11423eff"
   integrity sha512-+Ilqi8hgHSAdhlQ3s12CAVNd8H96ZkQBfYoXmArzZnOfAtVAJEiPDBirjByEblvG/4LPJmkL+nBqPO3A1YJAEg==
 
+jest-get-type@^27.5.1:
+  version "27.5.1"
+  resolved "https://registry.yarnpkg.com/jest-get-type/-/jest-get-type-27.5.1.tgz#3cd613c507b0f7ace013df407a1c1cd578bcb4f1"
+  integrity sha512-2KY95ksYSaK7DMBWQn6dQz3kqAf3BB64y2udeG+hv4KfSOb9qwcYQstTJc1KCbsix+wLZWZYN8t7nwX3GOBLRw==
+
 jest-haste-map@^27.3.1:
   version "27.3.1"
   resolved "https://registry.yarnpkg.com/jest-haste-map/-/jest-haste-map-27.3.1.tgz#7656fbd64bf48bda904e759fc9d93e2c807353ee"
@@ -7265,6 +7293,16 @@ jest-leak-detector@^27.3.1:
     jest-get-type "^27.3.1"
     pretty-format "^27.3.1"
 
+jest-matcher-utils@^27.0.0:
+  version "27.5.1"
+  resolved "https://registry.yarnpkg.com/jest-matcher-utils/-/jest-matcher-utils-27.5.1.tgz#9c0cdbda8245bc22d2331729d1091308b40cf8ab"
+  integrity sha512-z2uTx/T6LBaCoNWNFWwChLBKYxTMcGBRjAt+2SbP929/Fflb9aa5LGma654Rz8z9HLxsrUaYzxE9T/EFIL/PAw==
+  dependencies:
+    chalk "^4.0.0"
+    jest-diff "^27.5.1"
+    jest-get-type "^27.5.1"
+    pretty-format "^27.5.1"
+
 jest-matcher-utils@^27.3.1:
   version "27.3.1"
   resolved "https://registry.yarnpkg.com/jest-matcher-utils/-/jest-matcher-utils-27.3.1.tgz#257ad61e54a6d4044e080d85dbdc4a08811e9c1c"
@@ -9540,6 +9578,15 @@ pretty-format@^27.3.1:
     ansi-styles "^5.0.0"
     react-is "^17.0.1"
 
+pretty-format@^27.5.1:
+  version "27.5.1"
+  resolved "https://registry.yarnpkg.com/pretty-format/-/pretty-format-27.5.1.tgz#2181879fdea51a7a5851fb39d920faa63f01d88e"
+  integrity sha512-Qb1gy5OrP5+zDf2Bvnzdl3jsTf1qXVMazbvCoKhtKqVs4/YK4ozX4gKQJJVyNe+cajNPn0KoC0MC3FUmaHWEmQ==
+  dependencies:
+    ansi-regex "^5.0.1"
+    ansi-styles "^5.0.0"
+    react-is "^17.0.1"
+
 pretty-ms@^5.0.0:
   version "5.1.0"
   resolved "https://registry.yarnpkg.com/pretty-ms/-/pretty-ms-5.1.0.tgz#b906bdd1ec9e9799995c372e2b1c34f073f95384"