fix: unify timing report for concurrent linting (#20188)

jaymarvelz · web-flow · commit ae07f0b3334e · 2025-10-23T17:57:22.000+02:00
* fix: unify timing report for concurrent linting

* fix: handle missing worker_threads in non-Node environments

* refactor: export `disableDisplay()` and call it in `worker.js`

* chore: restore blank line after `use strict`

* fix: don’t print empty timing table on errors

* fix: suppress timing output if any worker fails
diff --git a/lib/eslint/eslint.js b/lib/eslint/eslint.js
@@ -17,6 +17,7 @@ const { pathToFileURL } = require("node:url");
 const { SHARE_ENV, Worker } = require("node:worker_threads");
 const { version } = require("../../package.json");
 const { defaultConfig } = require("../config/default-config");
+const timing = require("../linter/timing");
 
 const {
 	createDebug,
@@ -503,6 +504,11 @@ async function runWorkers(
 					worstNetLintingRatio,
 					netLintingRatio,
 				);
+
+				if (timing.enabled && indexedResults.timings) {
+					timing.mergeData(indexedResults.timings);
+				}
+
 				for (const result of indexedResults) {
 					const { index } = result;
 					delete result.index;
@@ -522,7 +528,17 @@ async function runWorkers(
 	for (let index = 0; index < workerCount; ++index) {
 		promises[index] = new Promise(workerExecutor);
 	}
-	await Promise.all(promises);
+
+	try {
+		await Promise.all(promises);
+	} catch (error) {
+		/*
+		 * If any worker fails, suppress timing display in the main thread
+		 * to avoid printing partial or misleading timing output.
+		 */
+		timing.disableDisplay();
+		throw error;
+	}
 
 	if (worstNetLintingRatio < LOW_NET_LINTING_RATIO) {
 		warnOnLowNetLintingRatio();
diff --git a/lib/eslint/worker.js b/lib/eslint/worker.js
@@ -29,6 +29,7 @@ const {
 	processOptions,
 } = require("./eslint-helpers");
 const { WarningService } = require("../services/warning-service");
+const timing = require("../linter/timing");
 
 const depsLoadedTime = hrtimeBigint();
 
@@ -39,7 +40,7 @@ const depsLoadedTime = hrtimeBigint();
 /** @typedef {import("../types").ESLint.LintResult} LintResult */
 /** @typedef {import("../types").ESLint.Options} ESLintOptions */
 /** @typedef {LintResult & { index?: number; }} IndexedLintResult */
-/** @typedef {IndexedLintResult[] & { netLintingDuration: bigint; }} WorkerLintResults */
+/** @typedef {IndexedLintResult[] & { netLintingDuration: bigint; timings?: Record<string, number>; }} WorkerLintResults */
 /**
  * @typedef {Object} WorkerData - Data passed to the worker thread.
  * @property {ESLintOptions | string} eslintOptionsOrURL - The unprocessed ESLint options or the URL of the options module.
@@ -57,6 +58,12 @@ const debug = createDebug(`eslint:worker:thread-${threadId}`);
 // Main
 //------------------------------------------------------------------------------
 
+/*
+ * Prevent timing module from printing profiling output from worker threads.
+ * The main thread is responsible for displaying any aggregated timings.
+ */
+timing.disableDisplay();
+
 debug("Dependencies loaded in %t", depsLoadedTime - startTime);
 
 (async () => {
@@ -158,5 +165,9 @@ debug("Dependencies loaded in %t", depsLoadedTime - startTime);
 	indexedResults.netLintingDuration =
 		lintingDuration - loadConfigTotalDuration - readFileCounter.duration;
 
+	if (timing.enabled) {
+		indexedResults.timings = timing.getData();
+	}
+
 	parentPort.postMessage(indexedResults);
 })();
diff --git a/lib/linter/timing.js b/lib/linter/timing.js
@@ -131,6 +131,7 @@ function display(data) {
 /* c8 ignore next */
 module.exports = (function () {
 	const data = Object.create(null);
+	let displayEnabled = true;
 
 	/**
 	 * Time the run
@@ -158,15 +159,51 @@ module.exports = (function () {
 		};
 	}
 
+	/**
+	 * Returns a shallow copy of the collected timings data.
+	 * @returns {Record<string, number>} mapping of ruleId to total time in ms
+	 */
+	function getData() {
+		return { ...data };
+	}
+
+	/**
+	 * Merges rule timing totals collected elsewhere into this process' totals.
+	 * @param {Record<string, number>} dataToMerge mapping of ruleId to total time in ms
+	 * @returns {void}
+	 */
+	function mergeData(dataToMerge) {
+		for (const [key, value] of Object.entries(dataToMerge)) {
+			if (typeof data[key] === "undefined") {
+				data[key] = 0;
+			}
+			data[key] += value;
+		}
+	}
+
+	/**
+	 * Disables printing of timing data on process exit.
+	 * Intended for worker threads or non-main contexts.
+	 * @returns {void}
+	 */
+	function disableDisplay() {
+		displayEnabled = false;
+	}
+
 	if (enabled) {
 		process.on("exit", () => {
-			display(data);
+			if (displayEnabled && Object.keys(data).length > 0) {
+				display(data);
+			}
 		});
 	}
 
 	return {
 		time,
 		enabled,
 		getListSize,
+		getData,
+		mergeData,
+		disableDisplay,
 	};
 })();
