fix: make sure generated name in config is stable across runs of Jest

CHANGELOG.md

@@ -11,6 +11,7 @@
 - `[jest-cli]` Do not execute any `globalSetup` or `globalTeardown` if there are no tests to execute ([#7745](https://github.com/facebook/jest/pull/7745))
 - `[jest-runtime]` Lock down version of `write-file-atomic` ([#7725](https://github.com/facebook/jest/pull/7725))
 - `[jest-cli]` Print log entries when logging happens after test environment is torn down ([#7731](https://github.com/facebook/jest/pull/7731))
+- `[jest-config]` Do not use a uuid as `name` since that breaks caching ([#7746](https://github.com/facebook/jest/pull/7746))
 
 ### Chore & Maintenance
 

e2e/__tests__/multiProjectRunner.test.js

@@ -425,6 +425,25 @@ test("doesn't bleed module file extensions resolution with multiple workers", ()
       };`,
   });
 
+  const {stdout: configOutput} = runJest(DIR, [
+    '--show-config',
+    '--projects',
+    'project1',
+    'project2',
+  ]);
+
+  const {configs} = JSON.parse(configOutput);
+
+  expect(configs).toHaveLength(2);
+
+  const [{name: name1}, {name: name2}] = configs;
+
+  expect(name1).toBeTruthy();
+  expect(name2).toBeTruthy();
+  expect(name1).toHaveLength(32);
+  expect(name2).toHaveLength(32);
+  expect(name1).not.toEqual(name2);
+
   const {stderr} = runJest(DIR, [
     '--no-watchman',
     '-w=2',

packages/jest-config/package.json

@@ -23,8 +23,7 @@
     "jest-validate": "^24.0.0",
     "micromatch": "^3.1.10",
     "pretty-format": "^24.0.0",
-    "realpath-native": "^1.0.2",
-    "uuid": "^3.3.2"
+    "realpath-native": "^1.0.2"
   },
   "engines": {
     "node": ">= 6"

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

@@ -6,16 +6,17 @@
  *
  */
 
+import crypto from 'crypto';
+import path from 'path';
 import {escapeStrForRegex} from 'jest-regex-util';
 import normalize from '../normalize';
 
-jest.mock('jest-resolve');
-jest.mock('path', () => jest.requireActual('path').posix);
+import {DEFAULT_JS_PATTERN} from '../constants';
 
-const path = require('path');
-const DEFAULT_JS_PATTERN = require('../constants').DEFAULT_JS_PATTERN;
 const DEFAULT_CSS_PATTERN = '^.+\\.(css)$';
 
+jest.mock('jest-resolve').mock('path', () => jest.requireActual('path').posix);
+
 let root;
 let expectedPathFooBar;
 let expectedPathFooQux;
@@ -46,16 +47,33 @@ beforeEach(() => {
   require('jest-resolve').findNodeModule = findNodeModule;
 });
 
-it('assigns a random 32-byte hash as a name to avoid clashes', () => {
+it('picks a name based on the rootDir', () => {
   const rootDir = '/root/path/foo';
-  const {name: name1} = normalize({rootDir}, {}).options;
-  const {name: name2} = normalize({rootDir}, {}).options;
-
-  expect(name1).toEqual(expect.any(String));
-  expect(name1).toHaveLength(32);
-  expect(name2).toEqual(expect.any(String));
-  expect(name2).toHaveLength(32);
-  expect(name1).not.toBe(name2);
+  const expected = crypto
+    .createHash('md5')
+    .update('/root/path/foo')
+    .digest('hex');
+  expect(
+    normalize(
+      {
+        rootDir,
+      },
+      {},
+    ).options.name,
+  ).toBe(expected);
+});
+
+it('keeps custom project name based on the projects rootDir', () => {
+  const name = 'test';
+  const options = normalize(
+    {
+      projects: [{name, rootDir: '/path/to/foo'}],
+      rootDir: '/root/path/baz',
+    },
+    {},
+  );
+
+  expect(options.options.projects[0].name).toBe(name);
 });
 
 it('keeps custom names based on the rootDir', () => {
@@ -70,6 +88,16 @@ it('keeps custom names based on the rootDir', () => {
   ).toBe('custom-name');
 });
 
+it('minimal config is stable across runs', () => {
+  const firstNormalization = normalize({rootDir: '/root/path/foo'}, {});
+  const secondNormalization = normalize({rootDir: '/root/path/foo'}, {});
+
+  expect(firstNormalization).toEqual(secondNormalization);
+  expect(JSON.stringify(firstNormalization)).toBe(
+    JSON.stringify(secondNormalization),
+  );
+});
+
 it('sets coverageReporters correctly when argv.json is set', () => {
   expect(
     normalize(

packages/jest-config/src/index.js

@@ -86,7 +86,12 @@ export function readConfig(
     rawOptions = readConfigFileAndSetRootDir(configPath);
   }
 
-  const {options, hasDeprecationWarnings} = normalize(rawOptions, argv);
+  const {options, hasDeprecationWarnings} = normalize(
+    rawOptions,
+    argv,
+    configPath,
+  );
+
   const {globalConfig, projectConfig} = groupOptions(options);
   return {
     configPath,
@@ -210,7 +215,7 @@ const groupOptions = (
   }),
 });
 
-const ensureNoDuplicateConfigs = (parsedConfigs, projects, rootConfigPath) => {
+const ensureNoDuplicateConfigs = (parsedConfigs, projects) => {
   const configPathMap = new Map();
 
   for (const config of parsedConfigs) {
@@ -299,7 +304,7 @@ export function readConfigs(
       })
       .map(root => readConfig(argv, root, true, configPath));
 
-    ensureNoDuplicateConfigs(parsedConfigs, projects, configPath);
+    ensureNoDuplicateConfigs(parsedConfigs, projects);
     configs = parsedConfigs.map(({projectConfig}) => projectConfig);
     if (!hasDeprecationWarnings) {
       hasDeprecationWarnings = parsedConfigs.some(

packages/jest-config/src/normalize.js

@@ -13,11 +13,11 @@ import type {
   DefaultOptions,
   ReporterConfig,
   GlobalConfig,
+  Path,
   ProjectConfig,
 } from 'types/Config';
 
 import crypto from 'crypto';
-import uuid from 'uuid/v4';
 import glob from 'glob';
 import path from 'path';
 import {ValidationError, validate} from 'jest-validate';
@@ -264,12 +264,16 @@ const normalizePreprocessor = (options: InitialOptions): InitialOptions => {
   return options;
 };
 
-const normalizeMissingOptions = (options: InitialOptions): InitialOptions => {
+const normalizeMissingOptions = (
+  options: InitialOptions,
+  configPath: ?Path,
+): InitialOptions => {
   if (!options.name) {
     options.name = crypto
       .createHash('md5')
       .update(options.rootDir)
-      .update(uuid())
+      // In case we load config from some path that has the same root dir
+      .update(configPath || '')
       .digest('hex');
   }
 
@@ -375,7 +379,11 @@ const showTestPathPatternError = (testPathPattern: string) => {
   );
 };
 
-export default function normalize(options: InitialOptions, argv: Argv) {
+export default function normalize(
+  options: InitialOptions,
+  argv: Argv,
+  configPath: ?Path,
+) {
   const {hasDeprecationWarnings} = validate(options, {
     comment: DOCUMENTATION_NOTE,
     deprecatedConfig: DEPRECATED_CONFIG,
@@ -394,7 +402,10 @@ export default function normalize(options: InitialOptions, argv: Argv) {
 
   options = normalizePreprocessor(
     normalizeReporters(
-      normalizeMissingOptions(normalizeRootDir(setFromArgv(options, argv))),
+      normalizeMissingOptions(
+        normalizeRootDir(setFromArgv(options, argv)),
+        configPath,
+      ),
     ),
   );