From b525e61a72845976692060a7bc82b987653a1380 Mon Sep 17 00:00:00 2001
From: Tobias Koppers <tobias.koppers@googlemail.com>
Date: Fri, 9 Apr 2021 17:51:58 +0200
Subject: [PATCH] make sure that invalid event is only reported once

---
 lib/Watching.js            | 10 ++++++++--
 test/MultiCompiler.test.js | 29 ++++++++++++++++++++---------
 2 files changed, 28 insertions(+), 11 deletions(-)

diff --git a/lib/Watching.js b/lib/Watching.js
index d3c513a401f..254c80f6809 100644
--- a/lib/Watching.js
+++ b/lib/Watching.js
@@ -53,6 +53,7 @@ class Watching {
 		this.compiler = compiler;
 		this.running = false;
 		this._initial = true;
+		this._invalidReported = true;
 		this._needRecords = true;
 		this.watcher = undefined;
 		this.pausedWatcher = undefined;
@@ -83,6 +84,7 @@ class Watching {
 				});
 			}
 			this.invalid = false;
+			this._invalidReported = false;
 			this.compiler.hooks.watchRun.callAsync(this.compiler, err => {
 				if (err) return this._done(err);
 				const onCompiled = (err, compilation) => {
@@ -270,7 +272,10 @@ class Watching {
 				this._onChange();
 			},
 			(fileName, changeTime) => {
-				this.compiler.hooks.invalid.call(fileName, changeTime);
+				if (!this._invalidReported) {
+					this._invalidReported = true;
+					this.compiler.hooks.invalid.call(fileName, changeTime);
+				}
 				this._onInvalid();
 			}
 		);
@@ -284,7 +289,8 @@ class Watching {
 		if (callback) {
 			this.callbacks.push(callback);
 		}
-		if (!this._initial) {
+		if (!this._invalidReported) {
+			this._invalidReported = true;
 			this.compiler.hooks.invalid.call(null, Date.now());
 		}
 		this._invalidate();
diff --git a/test/MultiCompiler.test.js b/test/MultiCompiler.test.js
index 319e9b4470d..0c785d44058 100644
--- a/test/MultiCompiler.test.js
+++ b/test/MultiCompiler.test.js
@@ -246,6 +246,9 @@ describe("MultiCompiler", function () {
 		};
 		const events = [];
 		compiler.compilers.forEach(c => {
+			c.hooks.invalid.tap("test", () => {
+				events.push(`${c.name} invalid`);
+			});
 			c.hooks.watchRun.tap("test", () => {
 				events.push(`${c.name} run`);
 			});
@@ -273,15 +276,15 @@ describe("MultiCompiler", function () {
 					expect(compiler.compilers[0].modifiedFiles).toBe(undefined);
 					expect(compiler.compilers[0].removedFiles).toBe(undefined);
 					expect(events).toMatchInlineSnapshot(`
-							Array [
-							  "b run",
-							  "b done",
-							  "c run",
-							  "c done",
-							  "a run",
-							  "a done",
-							]
-					`);
+				Array [
+				  "b run",
+				  "b done",
+				  "c run",
+				  "c done",
+				  "a run",
+				  "a done",
+				]
+			`);
 					events.length = 0;
 					// wait until watching begins
 					setTimeout(() => {
@@ -301,8 +304,10 @@ describe("MultiCompiler", function () {
 					expect(compiler.compilers[1].removedFiles).toEqual(new Set());
 					expect(events).toMatchInlineSnapshot(`
 				Array [
+				  "b invalid",
 				  "b run",
 				  "b done",
+				  "a invalid",
 				  "a run",
 				  "a done",
 				]
@@ -317,10 +322,13 @@ describe("MultiCompiler", function () {
 			`);
 					expect(events).toMatchInlineSnapshot(`
 				Array [
+				  "b invalid",
 				  "b run",
 				  "b done",
+				  "a invalid",
 				  "a run",
 				  "a done",
+				  "a invalid",
 				  "a run",
 				  "a done",
 				]
@@ -344,10 +352,13 @@ describe("MultiCompiler", function () {
 			`);
 					expect(events).toMatchInlineSnapshot(`
 				Array [
+				  "b invalid",
+				  "c invalid",
 				  "b run",
 				  "b done",
 				  "c run",
 				  "c done",
+				  "a invalid",
 				  "a run",
 				  "a done",
 				]