fix: limit number of workers when creating haste maps in projec… (#9259)

Author: thymikee

.vscode/settings.json

@@ -5,9 +5,7 @@
     "**/node_modules": true,
     "**/build": true
   },
-  "editor.formatOnSave": true,
-  "flow.useNPMPackagedFlow": true,
+  "eslint.autoFixOnSave": true,
   "javascript.validate.enable": false,
-  "jest.pathToJest": "yarn jest --",
-  "prettier.eslintIntegration": true
+  "jest.pathToJest": "yarn jest --"
 }

CHANGELOG.md

@@ -49,6 +49,7 @@
 - `[jest-config]` Fix Jest multi project runner still cannot handle exactly one project ([#8894](https://github.com/facebook/jest/pull/8894))
 - `[jest-console]` Add missing `console.group` calls to `NullConsole` ([#9024](https://github.com/facebook/jest/pull/9024))
 - `[jest-core]` Don't include unref'd timers in --detectOpenHandles results ([#8941](https://github.com/facebook/jest/pull/8941))
+- `[jest-core]` Limit number of workers when creating haste maps in projects ([#9259](https://github.com/facebook/jest/pull/9259))
 - `[jest-diff]` Do not inverse format if line consists of one change ([#8903](https://github.com/facebook/jest/pull/8903))
 - `[jest-diff]` Rename some new options and change their default values ([#9077](https://github.com/facebook/jest/pull/9077))
 - `[jest-fake-timers]` `getTimerCount` will not include cancelled immediates ([#8764](https://github.com/facebook/jest/pull/8764))

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

@@ -122,7 +122,10 @@ const buildContextsAndHasteMaps = async (
       createDirectory(config.cacheDirectory);
       const hasteMapInstance = Runtime.createHasteMap(config, {
         console: new CustomConsole(outputStream, outputStream),
-        maxWorkers: globalConfig.maxWorkers,
+        maxWorkers: Math.max(
+          1,
+          Math.floor(globalConfig.maxWorkers / configs.length),
+        ),
         resetCache: !config.cache,
         watch: globalConfig.watch || globalConfig.watchAll,
         watchman: globalConfig.watchman,

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

@@ -35,7 +35,6 @@ export function run(cliArgv?: Config.Argv, cliInfo?: Array<string>) {
       .version(false)
       .options(args.options).argv;
 
-    // @ts-ignore: fix this at some point
     validateCLIOptions(argv, {...args.options, deprecationEntries});
   }
 
@@ -63,8 +62,6 @@ export function run(cliArgv?: Config.Argv, cliInfo?: Array<string>) {
     const info = cliInfo ? ', ' + cliInfo.join(', ') : '';
     console.log(`Using Jest Runtime v${VERSION}${info}`);
   }
-  // TODO: Figure this out
-  // @ts-ignore: this might not have the correct arguments
   const options = readConfig(argv, root);
   const globalConfig = options.globalConfig;
   // Always disable automocking in scripts.

packages/jest-worker/README.md

@@ -83,7 +83,7 @@ By default, no process is bound to any worker.
 
 The arguments that will be passed to the `setup` method during initialization.
 
-#### `workerPool: (workerPath: string, options?: WorkerPoolOptions) => WorkerPoolInterface` (optional)
+#### `WorkerPool: (workerPath: string, options?: WorkerPoolOptions) => WorkerPoolInterface` (optional)
 
 Provide a custom worker pool to be used for spawning child processes. By default, Jest will use a node thread pool if available and fall back to child process threads.