fix: verify rootDir and all roots are directories

CHANGELOG.md

@@ -9,6 +9,7 @@
 
 - `[jest-config]` Treat `setupFilesAfterEnv` like `setupFiles` when normalizing configs against presets ([#9495](https://github.com/facebook/jest/pull/9495))
 - `[jest-config]` Support `.mjs` config files on Windows as well ([#9558](https://github.com/facebook/jest/pull/9558))
+- `[jest-config]` Verify `rootDir` and all `roots` are directories ([#9569](https://github.com/facebook/jest/pull/9569))
 - `[jest-cli]` Set `coverageProvider` correctly when provided in config ([#9562](https://github.com/facebook/jest/pull/9562))
 - `[jest-matcher-utils]` Fix diff highlight of symbol-keyed object. ([#9499](https://github.com/facebook/jest/pull/9499))
 - `[@jest/reporters]` Notifications should be fire&forget rather than having a timeout ([#9567](https://github.com/facebook/jest/pull/9567))

e2e/__tests__/existentRoots.test.ts

@@ -0,0 +1,76 @@
+/**
+ * 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 * as path from 'path';
+import {tmpdir} from 'os';
+import {skipSuiteOnWindows} from '@jest/test-utils';
+import {cleanup, writeFiles} from '../Utils';
+import runJest from '../runJest';
+
+const DIR = path.resolve(tmpdir(), 'existent-roots');
+
+beforeEach(() => cleanup(DIR));
+afterAll(() => cleanup(DIR));
+
+skipSuiteOnWindows();
+
+function writeConfig(rootDir: string, roots?: Array<string>) {
+  writeFiles(DIR, {
+    'jest.config.js': `
+      module.exports = ${JSON.stringify({rootDir, roots}, null, 2)};
+    `,
+    'package.json': '{}',
+  });
+}
+
+test('error when rootDir does not exist', () => {
+  const fakeRootDir = path.join(DIR, 'foobar');
+  writeConfig(fakeRootDir);
+
+  const {exitCode, stderr} = runJest(DIR);
+
+  expect(exitCode).toBe(1);
+  expect(stderr).toContain(
+    `Directory ${fakeRootDir} in the rootDir option was not found.`,
+  );
+});
+
+test('error when rootDir is a file', () => {
+  const fakeRootDir = path.join(DIR, 'jest.config.js');
+  writeConfig(fakeRootDir);
+
+  const {exitCode, stderr} = runJest(DIR);
+
+  expect(exitCode).toBe(1);
+  expect(stderr).toContain(
+    `${fakeRootDir} in the rootDir option is not a directory.`,
+  );
+});
+
+test('error when roots directory does not exist', () => {
+  const fakeRootDir = path.join(DIR, 'foobar');
+  writeConfig(DIR, ['<rootDir>', fakeRootDir]);
+
+  const {exitCode, stderr} = runJest(DIR);
+
+  expect(exitCode).toBe(1);
+  expect(stderr).toContain(
+    `Directory ${fakeRootDir} in the roots[1] option was not found.`,
+  );
+});
+
+test('error when roots is a file', () => {
+  const fakeRootDir = path.join(DIR, 'jest.config.js');
+  writeConfig(DIR, ['<rootDir>', fakeRootDir]);
+
+  const {exitCode, stderr} = runJest(DIR);
+
+  expect(exitCode).toBe(1);
+  expect(stderr).toContain(
+    `${fakeRootDir} in the roots[1] option is not a directory.`,
+  );
+});

packages/jest-config/src/__tests__/normalize.test.js

@@ -16,7 +16,17 @@ import {DEFAULT_JS_PATTERN} from '../constants';
 
 const DEFAULT_CSS_PATTERN = '^.+\\.(css)$';
 
-jest.mock('jest-resolve').mock('path', () => jest.requireActual('path').posix);
+jest
+  .mock('jest-resolve')
+  .mock('path', () => jest.requireActual('path').posix)
+  .mock('fs', () => {
+    const realFs = jest.requireActual('fs');
+
+    return {
+      ...realFs,
+      statSync: () => ({isDirectory: () => true}),
+    };
+  });
 
 let root;
 let expectedPathFooBar;

packages/jest-config/src/normalize.ts

@@ -6,6 +6,7 @@
  */
 
 import {createHash} from 'crypto';
+import {statSync} from 'fs';
 import * as path from 'path';
 import {sync as glob} from 'glob';
 import {Config} from '@jest/types';
@@ -46,6 +47,39 @@ type AllOptions = Config.ProjectConfig & Config.GlobalConfig;
 const createConfigError = (message: string) =>
   new ValidationError(ERROR, message, DOCUMENTATION_NOTE);
 
+function verifyDirectoryExists(path: Config.Path, key: string) {
+  try {
+    const rootStat = statSync(path);
+
+    if (!rootStat.isDirectory()) {
+      throw createConfigError(
+        `  ${chalk.bold(path)} in the ${chalk.bold(
+          key,
+        )} option is not a directory.`,
+      );
+    }
+  } catch (err) {
+    if (err instanceof ValidationError) {
+      throw err;
+    }
+
+    if (err.code === 'ENOENT') {
+      throw createConfigError(
+        `  Directory ${chalk.bold(path)} in the ${chalk.bold(
+          key,
+        )} option was not found.`,
+      );
+    }
+
+    // Not sure in which cases `statSync` can throw, so let's just show the underlying error to the user
+    throw createConfigError(
+      `  Got an error trying to find ${chalk.bold(path)} in the ${chalk.bold(
+        key,
+      )} option.\n\n  Error was: ${err.message}`,
+    );
+  }
+}
+
 // TS 3.5 forces us to split these into 2
 const mergeModuleNameMapperWithPreset = (
   options: Config.InitialOptionsWithRootDir,
@@ -366,6 +400,8 @@ const normalizeRootDir = (
     // ignored
   }
 
+  verifyDirectoryExists(options.rootDir, 'rootDir');
+
   return {
     ...options,
     rootDir: options.rootDir,
@@ -916,6 +952,10 @@ export default function normalize(
     return newOptions;
   }, newOptions);
 
+  newOptions.roots.forEach((root, i) => {
+    verifyDirectoryExists(root, `roots[${i}]`);
+  });
+
   try {
     // try to resolve windows short paths, ignoring errors (permission errors, mostly)
     newOptions.cwd = realpath(process.cwd());

packages/jest-core/src/__tests__/SearchSource.test.ts

@@ -15,6 +15,21 @@ import SearchSource, {SearchResult} from '../SearchSource';
 
 jest.setTimeout(15000);
 
+jest.mock('fs', () => {
+  const realFs = jest.requireActual('fs');
+
+  return {
+    ...realFs,
+    statSync: path => {
+      if (path === '/foo/bar/prefix') {
+        return {isDirectory: () => true};
+      }
+
+      return realFs.statSync(path);
+    },
+  };
+});
+
 const rootDir = path.resolve(__dirname, 'test_root');
 const testRegex = path.sep + '__testtests__' + path.sep;
 const testMatch = ['**/__testtests__/**/*'];