Preserve symlinks when node is configured to do so

.gitignore

@@ -6,6 +6,7 @@
 /examples/*/node_modules/
 /examples/mongodb/globalConfig.json
 
+/e2e/preserve-symlinks/*
 /e2e/*/node_modules
 /e2e/*/.pnp
 /e2e/*/.pnp.js

CHANGELOG.md

@@ -2,6 +2,8 @@
 
 ### Features
 
+- `[*]` Respect NODE_PRESERVE_SYMLINKS environment variable and --preserve-symlinks flag when resolving file paths ([#9732](https://github.com/facebook/jest/pull/9732))
+
 ### Fixes
 
 - `[jest-jasmine2]` Don't run `beforeAll` / `afterAll` in skipped describe block ([#9931](https://github.com/facebook/jest/pull/9931))

e2e/__tests__/__snapshots__/moduleNameMapper.test.ts.snap

@@ -36,7 +36,7 @@ FAIL __tests__/index.js
       12 | module.exports = () => 'test';
       13 | 
 
-      at createNoMappedModuleFoundError (../../packages/jest-resolve/build/index.js:545:17)
+      at createNoMappedModuleFoundError (../../packages/jest-resolve/build/index.js:561:17)
       at Object.require (index.js:10:1)
 `;
 
@@ -65,6 +65,6 @@ FAIL __tests__/index.js
       12 | module.exports = () => 'test';
       13 | 
 
-      at createNoMappedModuleFoundError (../../packages/jest-resolve/build/index.js:545:17)
+      at createNoMappedModuleFoundError (../../packages/jest-resolve/build/index.js:561:17)
       at Object.require (index.js:10:1)
 `;

e2e/__tests__/__snapshots__/resolveNoFileExtensions.test.ts.snap

@@ -37,6 +37,6 @@ FAIL __tests__/test.js
         |                  ^
       9 | 
 
-      at Resolver.resolveModule (../../packages/jest-resolve/build/index.js:299:11)
+      at Resolver.resolveModule (../../packages/jest-resolve/build/index.js:315:11)
       at Object.require (index.js:8:18)
 `;

e2e/__tests__/preserveSymlinks.ts

@@ -0,0 +1,131 @@
+/**
+ * Copyright (c) Facebook, Inc. and its affiliates. All Rights Reserved.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
+import {join, resolve} from 'path';
+import {
+  existsSync,
+  mkdirSync,
+  rmdirSync,
+  symlinkSync,
+  unlinkSync,
+} from 'graceful-fs';
+
+import runJest from '../runJest';
+import {extractSummary} from '../Utils';
+import HasteMap = require('jest-haste-map');
+
+const destRoot = resolve(__dirname, '../preserve-symlinks');
+const srcRoot = resolve(__dirname, '../symlinked-source-dir');
+
+const files = [
+  'package.json',
+  'a.js',
+  'b.js',
+  'ab.js',
+  '__tests__/a.test.js',
+  '__tests__/b.test.js',
+  '__tests__/ab.test.js',
+];
+
+function cleanup() {
+  files
+    .map(f => join(destRoot, f))
+    .filter(f => existsSync(f))
+    .forEach(f => {
+      unlinkSync(f);
+    });
+  if (existsSync(join(destRoot, '__tests__'))) {
+    rmdirSync(join(destRoot, '__tests__'));
+  }
+  if (existsSync(destRoot)) {
+    rmdirSync(destRoot);
+  }
+}
+
+beforeAll(() => {
+  cleanup();
+  mkdirSync(destRoot);
+  mkdirSync(join(destRoot, '__tests__'));
+  files.forEach(f => {
+    symlinkSync(join(srcRoot, f), join(destRoot, f));
+  });
+});
+
+afterAll(() => {
+  cleanup();
+});
+
+test('preserving symlinks with environment variable', () => {
+  const {stderr, exitCode} = runJest('preserve-symlinks', ['--no-watchman'], {
+    preserveSymlinks: '1',
+  });
+  const {summary, rest} = extractSummary(stderr);
+  expect(exitCode).toEqual(0);
+  expect(rest.split('\n').length).toEqual(3);
+  expect(rest).toMatch('PASS __tests__/ab.test.js');
+  expect(rest).toMatch('PASS __tests__/a.test.js');
+  expect(rest).toMatch('PASS __tests__/b.test.js');
+  expect(summary).toMatch('Test Suites: 3 passed, 3 total');
+  expect(summary).toMatch('Tests:       3 passed, 3 total');
+  expect(summary).toMatch('Snapshots:   0 total');
+});
+
+test('preserving symlinks with --preserve-symlinks node flag', () => {
+  const {stderr, exitCode} = runJest('preserve-symlinks', ['--no-watchman'], {
+    nodeFlags: ['--preserve-symlinks'],
+  });
+  const {summary, rest} = extractSummary(stderr);
+  expect(exitCode).toEqual(0);
+  expect(rest.split('\n').length).toEqual(3);
+  expect(rest).toMatch('PASS __tests__/ab.test.js');
+  expect(rest).toMatch('PASS __tests__/a.test.js');
+  expect(rest).toMatch('PASS __tests__/b.test.js');
+  expect(summary).toMatch('Test Suites: 3 passed, 3 total');
+  expect(summary).toMatch('Tests:       3 passed, 3 total');
+  expect(summary).toMatch('Snapshots:   0 total');
+});
+
+test('hasteMap finds symlinks correctly', async () => {
+  const options = {
+    extensions: ['js'],
+    forceNodeFilesystemAPI: true,
+    maxWorkers: 2,
+    mocksPattern: '',
+    name: 'tmp',
+    platforms: [],
+    preserveSymlinks: true,
+    retainAllFiles: true,
+    rootDir: resolve(__dirname, '../preserve-symlinks'),
+    roots: [resolve(__dirname, '../preserve-symlinks')],
+    useWatchman: false,
+    watch: false,
+  };
+  const hasteMap = new HasteMap(options);
+  const result = await hasteMap.build();
+  const files = result.hasteFS
+    .getAllFiles()
+    .map(f => f.split('preserve-symlinks').pop());
+
+  const expectedFiles = [
+    join('/__tests__', 'a.test.js'),
+    join('/__tests__', 'ab.test.js'),
+    join('/__tests__', 'b.test.js'),
+    join('/', 'a.js'),
+    join('/', 'ab.js'),
+    join('/', 'b.js'),
+  ];
+
+  expectedFiles.forEach(f => {
+    expect(files).toContain(f);
+  });
+});
+
+test('no preserve symlinks configuration', () => {
+  const {exitCode, stdout} = runJest('preserve-symlinks', ['--no-watchman']);
+  expect(exitCode).toEqual(1);
+  expect(stdout).toMatch('No tests found, exiting with code 1');
+});

e2e/runJest.ts

@@ -18,6 +18,8 @@ import {normalizeIcons} from './Utils';
 const JEST_PATH = path.resolve(__dirname, '../packages/jest-cli/bin/jest.js');
 
 type RunJestOptions = {
+  preserveSymlinks?: string;
+  nodeFlags?: Array<string>;
   nodeOptions?: string;
   nodePath?: string;
   skipPkgJsonCheck?: boolean; // don't complain if can't find package.json
@@ -74,11 +76,15 @@ function spawnJest(
     );
   }
   const env = Object.assign({}, process.env, {FORCE_COLOR: '0'});
-
   if (options.nodeOptions) env['NODE_OPTIONS'] = options.nodeOptions;
   if (options.nodePath) env['NODE_PATH'] = options.nodePath;
+  if (options.preserveSymlinks)
+    env['NODE_PRESERVE_SYMLINKS'] = options.preserveSymlinks;
 
   const spawnArgs = [JEST_PATH, ...args];
+  if (options.nodeFlags) {
+    spawnArgs.unshift(...options.nodeFlags);
+  }
   const spawnOptions = {
     cwd: dir,
     env,

e2e/symlinked-source-dir/__tests__/a.test.js

@@ -0,0 +1,12 @@
+/**
+ * Copyright (c) Facebook, Inc. and its affiliates. All Rights Reserved.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ *
+ */
+const a = require('../a');
+
+test('a', () => {
+  expect(a()).toEqual('a');
+});

e2e/symlinked-source-dir/__tests__/ab.test.js

@@ -0,0 +1,12 @@
+/**
+ * Copyright (c) Facebook, Inc. and its affiliates. All Rights Reserved.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ *
+ */
+const ab = require('../ab');
+
+test('ab', () => {
+  expect(ab()).toEqual('ab');
+});

e2e/symlinked-source-dir/__tests__/b.test.js

@@ -0,0 +1,12 @@
+/**
+ * Copyright (c) Facebook, Inc. and its affiliates. All Rights Reserved.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ *
+ */
+const b = require('../b');
+
+test('b', () => {
+  expect(b()).toEqual('b');
+});

e2e/symlinked-source-dir/a.js

@@ -0,0 +1,10 @@
+/**
+ * Copyright (c) Facebook, Inc. and its affiliates. All Rights Reserved.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ *
+ */
+module.exports = function a() {
+  return 'a';
+};

e2e/symlinked-source-dir/ab.js

@@ -0,0 +1,13 @@
+/**
+ * Copyright (c) Facebook, Inc. and its affiliates. All Rights Reserved.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ *
+ */
+const a = require('./a');
+const b = require('./b');
+
+module.exports = function ab() {
+  return a() + b();
+};

e2e/symlinked-source-dir/b.js

@@ -0,0 +1,10 @@
+/**
+ * Copyright (c) Facebook, Inc. and its affiliates. All Rights Reserved.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ *
+ */
+module.exports = function b() {
+  return 'b';
+};

e2e/symlinked-source-dir/package.json

@@ -0,0 +1,5 @@
+{
+  "jest": {
+    "testEnvironment": "node"
+  }
+}

packages/jest-cli/package.json

@@ -25,6 +25,7 @@
     "jest-validate": "^25.5.0",
     "prompts": "^2.0.1",
     "realpath-native": "^2.0.0",
+    "should-preserve-links": "^1.0.4",
     "yargs": "^15.3.1"
   },
   "devDependencies": {

packages/jest-cli/should-preserve-links.d.ts

@@ -0,0 +1,10 @@
+/**
+ * Copyright (c) Facebook, Inc. and its affiliates. All Rights Reserved.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
+declare module 'should-preserve-links' {
+  export default function shouldPreserveLinks(): boolean;
+}

packages/jest-cli/src/cli/index.ts

@@ -15,10 +15,16 @@ import {getVersion, runCLI} from '@jest/core';
 import chalk = require('chalk');
 import exit = require('exit');
 import yargs = require('yargs');
-import {sync as realpath} from 'realpath-native';
+import {sync as _realpath} from 'realpath-native';
+import shouldPreserveSymlinks from 'should-preserve-links';
 import init from '../init';
 import * as args from './args';
 
+const preserveSymlinks = shouldPreserveSymlinks();
+function realpath(p: string) {
+  return preserveSymlinks ? p : _realpath(p);
+}
+
 export async function run(
   maybeArgv?: Array<string>,
   project?: Config.Path,

packages/jest-cli/src/init/index.ts

@@ -9,8 +9,9 @@ import * as path from 'path';
 import * as fs from 'graceful-fs';
 import chalk = require('chalk');
 import prompts = require('prompts');
-import {sync as realpath} from 'realpath-native';
+import {sync as _realpath} from 'realpath-native';
 import {constants} from 'jest-config';
+import shouldPreserveSymlinks from 'should-preserve-links';
 import defaultQuestions, {testScriptQuestion} from './questions';
 import {MalformedPackageJsonError, NotFoundPackageJsonError} from './errors';
 import generateConfigFile from './generate_config_file';
@@ -32,6 +33,11 @@ type PromptsResults = {
   scripts: boolean;
 };
 
+const preserveSymlinks = shouldPreserveSymlinks();
+function realpath(p: string) {
+  return preserveSymlinks ? p : _realpath(p);
+}
+
 const getConfigFilename = (ext: string) => JEST_CONFIG_BASE_NAME + ext;
 
 export default async (

packages/jest-config/package.json

@@ -35,7 +35,8 @@
     "jest-validate": "^25.5.0",
     "micromatch": "^4.0.2",
     "pretty-format": "^25.5.0",
-    "realpath-native": "^2.0.0"
+    "realpath-native": "^2.0.0",
+    "should-preserve-links": "^1.0.4"
   },
   "devDependencies": {
     "@types/babel__core": "^7.0.4",

packages/jest-config/should-preserve-links.d.ts

@@ -0,0 +1,10 @@
+/**
+ * Copyright (c) Facebook, Inc. and its affiliates. All Rights Reserved.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
+declare module 'should-preserve-links' {
+  export default function shouldPreserveLinks(): boolean;
+}

packages/jest-config/src/getCacheDirectory.ts

@@ -7,7 +7,14 @@
 
 import * as path from 'path';
 import {tmpdir} from 'os';
-import {sync as realpath} from 'realpath-native';
+import {sync as _realpath} from 'realpath-native';
+
+import shouldPreserveSymlinks from 'should-preserve-links';
+
+const preserveSymlinks = shouldPreserveSymlinks();
+function realpath(p: string) {
+  return preserveSymlinks ? p : _realpath(p);
+}
 
 const getCacheDirectory = () => {
   const {getuid} = process;

packages/jest-config/src/index.ts

@@ -9,7 +9,8 @@ import * as path from 'path';
 import * as fs from 'graceful-fs';
 import type {Config} from '@jest/types';
 import chalk = require('chalk');
-import {sync as realpath} from 'realpath-native';
+import {sync as _realpath} from 'realpath-native';
+import shouldPreserveSymlinks from 'should-preserve-links';
 import {isJSONString, replaceRootDirInPath} from './utils';
 import normalize from './normalize';
 import resolveConfigPath from './resolveConfigPath';
@@ -23,6 +24,11 @@ export {default as descriptions} from './Descriptions';
 import * as constants from './constants';
 export {constants};
 
+const preserveSymlinks = shouldPreserveSymlinks();
+function realpath(p: string) {
+  return preserveSymlinks ? p : _realpath(p);
+}
+
 type ReadConfig = {
   configPath: Config.Path | null | undefined;
   globalConfig: Config.GlobalConfig;