watch: track worker thread entry files in --watch mode

lib/internal/modules/cjs/loader.js

@@ -329,6 +329,28 @@ function reportModuleNotFoundToWatchMode(basePath, extensions) {
   }
 }
 
+/**
+ * Tell the watch mode that a module was required, from within a worker thread.
+ * @param {string} filename Absolute path of the module
+ * @returns {void}
+ */
+function reportModuleToWatchModeFromWorker(filename) {
+  if (!shouldReportRequiredModules()) {
+    return;
+  }
+  const { isMainThread } = internalBinding('worker');
+  if (isMainThread) {
+    return;
+  }
+  // Lazy require to avoid circular dependency: worker_threads is loaded after
+  // the CJS loader is fully set up.
+  const { parentPort } = require('worker_threads');
+  if (!parentPort) {
+    return;
+  }
+  parentPort.postMessage({ 'watch:require': [filename] });
+}
+
 /**
  * Create a new module instance.
  * @param {string} id
@@ -1245,6 +1267,7 @@ Module._load = function(request, parent, isMain, internalResolveOptions = kEmpty
     relResolveCacheIdentifier = `${parent.path}\x00${request}`;
     const filename = relativeResolveCache[relResolveCacheIdentifier];
     reportModuleToWatchMode(filename);
+    reportModuleToWatchModeFromWorker(filename);
     if (filename !== undefined) {
       const cachedModule = Module._cache[filename];
       if (cachedModule !== undefined) {
@@ -1335,6 +1358,7 @@ Module._load = function(request, parent, isMain, internalResolveOptions = kEmpty
     }
 
     reportModuleToWatchMode(filename);
+    reportModuleToWatchModeFromWorker(filename);
     Module._cache[filename] = module;
     module[kIsCachedByESMLoader] = false;
     // If there are resolve hooks, carry the context information into the

lib/internal/modules/esm/loader.js

@@ -534,6 +534,16 @@ class ModuleLoader {
       const type = requestType === kRequireInImportedCJS ? 'require' : 'import';
       process.send({ [`watch:${type}`]: [url] });
     }
+    // Relay Events from worker to main thread
+    if (process.env.WATCH_REPORT_DEPENDENCIES && !process.send) {
+      const { isMainThread } = internalBinding('worker');
+      if (!isMainThread) {
+        const { parentPort } = require('worker_threads');
+        if (parentPort) {
+          parentPort.postMessage({ 'watch:import': [url] });
+        }
+      }
+    }
 
     // TODO(joyeecheung): update the module requests to use importAttributes as property names.
     const importAttributes = resolveResult.importAttributes ?? request.attributes;

lib/internal/worker.js

@@ -1,6 +1,7 @@
 'use strict';
 
 const {
+  ArrayIsArray,
   ArrayPrototypeForEach,
   ArrayPrototypeMap,
   ArrayPrototypePush,
@@ -333,6 +334,18 @@ class Worker extends EventEmitter {
       this[kPublicPort].on(event, (message) => this.emit(event, message));
     });
     setupPortReferencing(this[kPublicPort], this, 'message');
+
+    // Relay events from worker thread to watcher
+    if (process.env.WATCH_REPORT_DEPENDENCIES && process.send) {
+      this[kPublicPort].on('message', (message) => {
+        if (ArrayIsArray(message?.['watch:require'])) {
+          process.send({ 'watch:require': message['watch:require'] });
+        }
+        if (ArrayIsArray(message?.['watch:import'])) {
+          process.send({ 'watch:import': message['watch:import'] });
+        }
+      });
+    }
     this[kPort].postMessage({
       argv,
       type: messageTypes.LOAD_SCRIPT,

test/sequential/test-watch-mode-worker.mjs

@@ -0,0 +1,281 @@
+import * as common from '../common/index.mjs';
+import tmpdir from '../common/tmpdir.js';
+import assert from 'node:assert';
+import path from 'node:path';
+import { execPath } from 'node:process';
+import { describe, it } from 'node:test';
+import { spawn } from 'node:child_process';
+import { writeFileSync, readFileSync } from 'node:fs';
+import { inspect } from 'node:util';
+import { pathToFileURL } from 'node:url';
+import { createInterface } from 'node:readline';
+
+if (common.isIBMi)
+  common.skip('IBMi does not support `fs.watch()`');
+
+function restart(file, content = readFileSync(file)) {
+  writeFileSync(file, content);
+  const timer = setInterval(() => writeFileSync(file, content), common.platformTimeout(250));
+  return () => clearInterval(timer);
+}
+
+let tmpFiles = 0;
+function createTmpFile(content = 'console.log(\'running\');', ext = '.js', basename = tmpdir.path) {
+  const file = path.join(basename, `${tmpFiles++}${ext}`);
+  writeFileSync(file, content);
+  return file;
+}
+
+async function runWriteSucceed({
+  file,
+  watchedFile,
+  watchFlag = '--watch',
+  args = [file],
+  completed = 'Completed running',
+  restarts = 2,
+  options = {},
+  shouldFail = false,
+}) {
+  args.unshift('--no-warnings');
+  if (watchFlag !== null) args.unshift(watchFlag);
+
+  const child = spawn(execPath, args, { encoding: 'utf8', stdio: 'pipe', ...options });
+
+  let completes = 0;
+  let cancelRestarts = () => {};
+  let stderr = '';
+  const stdout = [];
+
+  child.stderr.on('data', (data) => {
+    stderr += data;
+  });
+
+  try {
+    for await (const data of createInterface({ input: child.stdout })) {
+      if (!data.startsWith('Waiting for graceful termination') &&
+          !data.startsWith('Gracefully restarted')) {
+        stdout.push(data);
+      }
+
+      if (data.startsWith(completed)) {
+        completes++;
+
+        if (completes === restarts) break;
+
+        if (completes === 1) {
+          cancelRestarts = restart(watchedFile);
+        }
+      }
+
+      if (!shouldFail && data.startsWith('Failed running')) break;
+    }
+  } finally {
+    child.kill();
+    cancelRestarts();
+  }
+
+  return { stdout, stderr, pid: child.pid };
+}
+
+tmpdir.refresh();
+const dir = tmpdir.path;
+
+describe('watch mode', { concurrency: !process.env.TEST_PARALLEL, timeout: 60_000 }, () => {
+  it('should watch changes to worker - cjs', async () => {
+    const worker = path.join(dir, 'worker.js');
+
+    writeFileSync(worker, `
+console.log('worker running');
+`);
+
+    const file = createTmpFile(`
+const { Worker } = require('node:worker_threads');
+const w = new Worker(${JSON.stringify(worker)});
+`, '.js', dir);
+
+    const { stderr, stdout } = await runWriteSucceed({
+      file,
+      watchedFile: worker,
+    });
+
+    assert.strictEqual(stderr, '');
+    assert.deepStrictEqual(stdout, [
+      'worker running',
+      `Completed running ${inspect(file)}. Waiting for file changes before restarting...`,
+      `Restarting ${inspect(file)}`,
+      'worker running',
+      `Completed running ${inspect(file)}. Waiting for file changes before restarting...`,
+    ]);
+  });
+
+  it('should watch changes to worker dependencies - cjs', async () => {
+    const dep = path.join(dir, 'dep.js');
+    const worker = path.join(dir, 'worker.js');
+
+    writeFileSync(dep, `
+module.exports = 'dep v1';
+`);
+
+    writeFileSync(worker, `
+const dep = require('./dep.js');
+console.log(dep);
+`);
+
+    const file = createTmpFile(`
+const { Worker } = require('node:worker_threads');
+const w = new Worker(${JSON.stringify(worker)});
+`, '.js', dir);
+
+    const { stderr, stdout } = await runWriteSucceed({
+      file,
+      watchedFile: dep,
+    });
+
+    assert.strictEqual(stderr, '');
+    assert.deepStrictEqual(stdout, [
+      'dep v1',
+      `Completed running ${inspect(file)}. Waiting for file changes before restarting...`,
+      `Restarting ${inspect(file)}`,
+      'dep v1',
+      `Completed running ${inspect(file)}. Waiting for file changes before restarting...`,
+    ]);
+  });
+
+  it('should watch changes to nested worker dependencies - cjs', async () => {
+    const subDep = path.join(dir, 'sub-dep.js');
+    const dep = path.join(dir, 'dep.js');
+    const worker = path.join(dir, 'worker.js');
+
+    writeFileSync(subDep, `
+module.exports = 'sub-dep v1';
+`);
+
+    writeFileSync(dep, `
+const subDep = require('./sub-dep.js');
+console.log(subDep);
+module.exports = 'dep v1';
+`);
+
+    writeFileSync(worker, `
+const dep = require('./dep.js');
+`);
+
+    const file = createTmpFile(`
+const { Worker } = require('node:worker_threads');
+const w = new Worker(${JSON.stringify(worker)});
+`, '.js', dir);
+
+    const { stderr, stdout } = await runWriteSucceed({
+      file,
+      watchedFile: subDep,
+    });
+
+    assert.strictEqual(stderr, '');
+    assert.deepStrictEqual(stdout, [
+      'sub-dep v1',
+      `Completed running ${inspect(file)}. Waiting for file changes before restarting...`,
+      `Restarting ${inspect(file)}`,
+      'sub-dep v1',
+      `Completed running ${inspect(file)}. Waiting for file changes before restarting...`,
+    ]);
+  });
+
+  it('should watch changes to worker - esm', async () => {
+    const worker = path.join(dir, 'worker.mjs');
+
+    writeFileSync(worker, `
+console.log('worker running');
+`);
+
+    const file = createTmpFile(`
+import { Worker } from 'node:worker_threads';
+new Worker(new URL(${JSON.stringify(pathToFileURL(worker))}));
+`, '.mjs', dir);
+
+    const { stderr, stdout } = await runWriteSucceed({
+      file,
+      watchedFile: worker,
+    });
+
+    assert.strictEqual(stderr, '');
+    assert.deepStrictEqual(stdout, [
+      'worker running',
+      `Completed running ${inspect(file)}. Waiting for file changes before restarting...`,
+      `Restarting ${inspect(file)}`,
+      'worker running',
+      `Completed running ${inspect(file)}. Waiting for file changes before restarting...`,
+    ]);
+  });
+
+  it('should watch changes to worker dependencies - esm', async () => {
+    const dep = path.join(dir, 'dep.mjs');
+    const worker = path.join(dir, 'worker.mjs');
+
+    writeFileSync(dep, `
+export default 'dep v1';
+`);
+
+    writeFileSync(worker, `
+import dep from ${JSON.stringify(pathToFileURL(dep))};
+console.log(dep);
+`);
+
+    const file = createTmpFile(`
+import { Worker } from 'node:worker_threads';
+new Worker(new URL(${JSON.stringify(pathToFileURL(worker))}));
+`, '.mjs', dir);
+
+    const { stderr, stdout } = await runWriteSucceed({
+      file,
+      watchedFile: dep,
+    });
+
+    assert.strictEqual(stderr, '');
+    assert.deepStrictEqual(stdout, [
+      'dep v1',
+      `Completed running ${inspect(file)}. Waiting for file changes before restarting...`,
+      `Restarting ${inspect(file)}`,
+      'dep v1',
+      `Completed running ${inspect(file)}. Waiting for file changes before restarting...`,
+    ]);
+  });
+
+  it('should watch changes to nested worker dependencies - esm', async () => {
+    const subDep = path.join(dir, 'sub-dep.mjs');
+    const dep = path.join(dir, 'dep.mjs');
+    const worker = path.join(dir, 'worker.mjs');
+
+    writeFileSync(subDep, `
+export default 'sub-dep v1';
+`);
+
+    writeFileSync(dep, `
+import subDep from ${JSON.stringify(pathToFileURL(subDep))};
+console.log(subDep);
+export default 'dep v1';
+`);
+
+    writeFileSync(worker, `
+import dep from ${JSON.stringify(pathToFileURL(dep))};
+`);
+
+    const file = createTmpFile(`
+import { Worker } from 'node:worker_threads';
+new Worker(new URL(${JSON.stringify(pathToFileURL(worker))}));
+`, '.mjs', dir);
+
+    const { stderr, stdout } = await runWriteSucceed({
+      file,
+      watchedFile: subDep,
+    });
+
+    assert.strictEqual(stderr, '');
+    assert.deepStrictEqual(stdout, [
+      'sub-dep v1',
+      `Completed running ${inspect(file)}. Waiting for file changes before restarting...`,
+      `Restarting ${inspect(file)}`,
+      'sub-dep v1',
+      `Completed running ${inspect(file)}. Waiting for file changes before restarting...`,
+    ]);
+  });
+});