track changes and removals correctly

purge filesystem correctly

lib/Compiler.js

@@ -230,6 +230,8 @@ class Compiler {
 		this.fileTimestamps = undefined;
 		/** @type {Map<string, FileSystemInfoEntry | "ignore" | null>} */
 		this.contextTimestamps = undefined;
+		/** @type {number} */
+		this.fsStartTime = undefined;
 
 		/** @type {ResolverFactory} */
 		this.resolverFactory = new ResolverFactory();
@@ -952,6 +954,7 @@ ${other}`);
 		childCompiler.removedFiles = this.removedFiles;
 		childCompiler.fileTimestamps = this.fileTimestamps;
 		childCompiler.contextTimestamps = this.contextTimestamps;
+		childCompiler.fsStartTime = this.fsStartTime;
 		childCompiler.cache = this.cache;
 		childCompiler.compilerPath = `${this.compilerPath}${compilerName}|${compilerIndex}|`;
 

lib/NormalModule.js

@@ -902,7 +902,7 @@ class NormalModule extends Module {
 			assetsInfo: undefined
 		};
 
-		const startTime = Date.now();
+		const startTime = compilation.compiler.fsStartTime || Date.now();
 
 		return this.doBuild(options, compilation, resolver, fs, err => {
 			// if we have an error mark module as failed and exit

lib/Watching.js

@@ -90,9 +90,13 @@ class Watching {
 		this.running = true;
 		if (this.watcher) {
 			this.pausedWatcher = this.watcher;
+			this.lastWatcherStartTime = Date.now();
 			this.watcher.pause();
 			this.watcher = null;
+		} else if (!this.lastWatcherStartTime) {
+			this.lastWatcherStartTime = Date.now();
 		}
+		this.compiler.fsStartTime = Date.now();
 		this._mergeWithCollected(
 			changedFiles ||
 				(this.pausedWatcher &&
@@ -104,6 +108,19 @@ class Watching {
 					this.pausedWatcher.getAggregatedRemovals &&
 					this.pausedWatcher.getAggregatedRemovals()))
 		);
+
+		this.compiler.modifiedFiles = this._collectedChangedFiles;
+		this._collectedChangedFiles = undefined;
+		this.compiler.removedFiles = this._collectedRemovedFiles;
+		this._collectedRemovedFiles = undefined;
+
+		this.compiler.fileTimestamps =
+			fileTimeInfoEntries ||
+			(this.pausedWatcher && this.pausedWatcher.getFileTimeInfoEntries());
+		this.compiler.contextTimestamps =
+			contextTimeInfoEntries ||
+			(this.pausedWatcher && this.pausedWatcher.getContextTimeInfoEntries());
+
 		const run = () => {
 			if (this.compiler.idle) {
 				return this.compiler.cache.endIdle(err => {
@@ -120,19 +137,6 @@ class Watching {
 					run();
 				});
 			}
-
-			this.compiler.modifiedFiles = this._collectedChangedFiles;
-			this._collectedChangedFiles = undefined;
-			this.compiler.removedFiles = this._collectedRemovedFiles;
-			this._collectedRemovedFiles = undefined;
-
-			this.compiler.fileTimestamps =
-				fileTimeInfoEntries ||
-				(this.pausedWatcher && this.pausedWatcher.getFileTimeInfoEntries());
-			this.compiler.contextTimestamps =
-				contextTimeInfoEntries ||
-				(this.pausedWatcher && this.pausedWatcher.getContextTimeInfoEntries());
-
 			this.invalid = false;
 			this._invalidReported = false;
 			this.compiler.hooks.watchRun.callAsync(this.compiler, err => {
@@ -295,7 +299,7 @@ class Watching {
 			files,
 			dirs,
 			missing,
-			this.startTime,
+			this.lastWatcherStartTime,
 			this.watchOptions,
 			(
 				err,
@@ -309,6 +313,7 @@ class Watching {
 					this.compiler.removedFiles = undefined;
 					this.compiler.fileTimestamps = undefined;
 					this.compiler.contextTimestamps = undefined;
+					this.compiler.fsStartTime = undefined;
 					return this.handler(err);
 				}
 				this._invalidate(
@@ -357,6 +362,7 @@ class Watching {
 		}
 
 		if (this.running) {
+			this._mergeWithCollected(changedFiles, removedFiles);
 			this.invalid = true;
 		} else {
 			this._go(
@@ -399,6 +405,7 @@ class Watching {
 			this.compiler.removedFiles = undefined;
 			this.compiler.fileTimestamps = undefined;
 			this.compiler.contextTimestamps = undefined;
+			this.compiler.fsStartTime = undefined;
 			const shutdown = () => {
 				this.compiler.cache.shutdown(err => {
 					this.compiler.hooks.watchClose.call();

package.json

@@ -26,7 +26,7 @@
     "schema-utils": "^3.0.0",
     "tapable": "^2.1.1",
     "terser-webpack-plugin": "^5.1.1",
-    "watchpack": "^2.0.0",
+    "watchpack": "^2.2.0",
     "webpack-sources": "^2.1.1"
   },
   "peerDependenciesMeta": {

types.d.ts

@@ -1830,6 +1830,7 @@ declare class Compiler {
 	removedFiles: Set<string>;
 	fileTimestamps: Map<string, null | FileSystemInfoEntry | "ignore">;
 	contextTimestamps: Map<string, null | FileSystemInfoEntry | "ignore">;
+	fsStartTime: number;
 	resolverFactory: ResolverFactory;
 	infrastructureLogger: any;
 	options: WebpackOptionsNormalized;
@@ -11453,6 +11454,7 @@ declare abstract class Watching {
 	running: boolean;
 	watcher?: null | Watcher;
 	pausedWatcher?: null | Watcher;
+	lastWatcherStartTime?: number;
 	watch(
 		files: Iterable<string>,
 		dirs: Iterable<string>,

yarn.lock

@@ -6740,10 +6740,10 @@ wast-loader@^1.11.0:
   dependencies:
     wabt "1.0.0-nightly.20180421"
 
-watchpack@^2.0.0:
-  version "2.1.1"
-  resolved "https://registry.yarnpkg.com/watchpack/-/watchpack-2.1.1.tgz#e99630550fca07df9f90a06056987baa40a689c7"
-  integrity sha512-Oo7LXCmc1eE1AjyuSBmtC3+Wy4HcV8PxWh2kP6fOl8yTlNS7r0K9l1ao2lrrUza7V39Y3D/BbJgY8VeSlc5JKw==
+watchpack@^2.2.0:
+  version "2.2.0"
+  resolved "https://registry.yarnpkg.com/watchpack/-/watchpack-2.2.0.tgz#47d78f5415fe550ecd740f99fe2882323a58b1ce"
+  integrity sha512-up4YAn/XHgZHIxFBVCdlMiWDj6WaLKpwVeGQk2I5thdYxF/KmF0aaz6TfJZ/hfl1h/XlcDr7k1KH7ThDagpFaA==
   dependencies:
     glob-to-regexp "^0.4.1"
     graceful-fs "^4.1.2"