add getContext/FileTimestamps to watcher

get timestamps on invalidate

fixes #5970

lib/WatchIgnorePlugin.js

@@ -36,7 +36,7 @@ class IgnoringWatchFileSystem {
 		const ignoredFiles = files.filter(ignored);
 		const ignoredDirs = dirs.filter(ignored);
 
-		this.wfs.watch(files.filter(notIgnored), dirs.filter(notIgnored), missing, startTime, options, (err, filesModified, dirsModified, missingModified, fileTimestamps, dirTimestamps) => {
+		const watcher = this.wfs.watch(files.filter(notIgnored), dirs.filter(notIgnored), missing, startTime, options, (err, filesModified, dirsModified, missingModified, fileTimestamps, dirTimestamps) => {
 			if(err) return callback(err);
 
 			ignoredFiles.forEach(path => {
@@ -49,5 +49,24 @@ class IgnoringWatchFileSystem {
 
 			callback(err, filesModified, dirsModified, missingModified, fileTimestamps, dirTimestamps);
 		}, callbackUndelayed);
+
+		return {
+			close: () => watcher.close(),
+			pause: () => watcher.pause(),
+			getContextTimestamps: () => {
+				const dirTimestamps = watcher.getContextTimestamps();
+				ignoredDirs.forEach(path => {
+					dirTimestamps[path] = 1;
+				});
+				return dirTimestamps;
+			},
+			getFileTimestamps: () => {
+				const fileTimestamps = watcher.getFileTimestamps();
+				ignoredFiles.forEach(path => {
+					fileTimestamps[path] = 1;
+				});
+				return fileTimestamps;
+			}
+		};
 	}
 }

lib/Watching.js

@@ -111,7 +111,7 @@ class Watching {
 
 			this.compiler.fileTimestamps = fileTimestamps;
 			this.compiler.contextTimestamps = contextTimestamps;
-			this.invalidate();
+			this._invalidate();
 		}, (fileName, changeTime) => {
 			this.compiler.hooks.invalid.call(fileName, changeTime);
 		});
@@ -121,6 +121,14 @@ class Watching {
 		if(callback) {
 			this.callbacks.push(callback);
 		}
+		if(this.watcher) {
+			this.compiler.fileTimestamps = this.watcher.getFileTimestamps();
+			this.compiler.contextTimestamps = this.watcher.getContextTimestamps();
+		}
+		return this._invalidate();
+	}
+
+	_invalidate() {
 		if(this.watcher) {
 			this.pausedWatcher = this.watcher;
 			this.watcher.pause();

lib/node/NodeWatchFileSystem.js

@@ -64,6 +64,18 @@ class NodeWatchFileSystem {
 				if(this.watcher) {
 					this.watcher.pause();
 				}
+			},
+			getFileTimestamps: () => {
+				if(this.watcher)
+					return this.watcher.getTimes();
+				else
+					return {};
+			},
+			getContextTimestamps: () => {
+				if(this.watcher)
+					return this.watcher.getTimes();
+				else
+					return {};
 			}
 		};
 	}