watcher - set a lower debounce delay

src/vs/platform/files/node/watcher/nsfw/nsfwWatcherService.ts

@@ -204,13 +204,7 @@ export class NsfwWatcherService extends Disposable implements IWatcherService {
 				const normalizedEvents = normalizeFileChanges(this.normalizeEvents(events, request, realBasePathDiffers, realBasePathLength));
 				this.emitEvents(normalizedEvents);
 			});
-		}, {
-			errorCallback: error => {
-				if (!watcher.token.isCancellationRequested) {
-					this.onError(error, watcher); // error handling only if we are not disposed yet
-				}
-			}
-		}).then(async nsfwWatcher => {
+		}, this.getOptions(watcher)).then(async nsfwWatcher => {
 
 			// Begin watching unless disposed already
 			if (!watcher.token.isCancellationRequested) {
@@ -225,6 +219,23 @@ export class NsfwWatcherService extends Disposable implements IWatcherService {
 		});
 	}
 
+	protected getOptions(watcher: IWatcher): nsfw.Options {
+		return {
+
+			// We must install an error callback, otherwise any error
+			// that is thrown from the watcher will result in process exit
+			errorCallback: error => {
+				if (!watcher.token.isCancellationRequested) {
+					this.onError(error, watcher); // error handling only if we are not disposed yet
+				}
+			},
+
+			// The default delay of NSFW is 500 but we already do some
+			// debouncing in our code so we reduce the delay slightly
+			debounceMS: 100
+		};
+	}
+
 	private emitEvents(events: IDiskFileChange[]): void {
 
 		// Send outside

src/vs/platform/files/node/watcher/watcher.ts

@@ -50,7 +50,7 @@ export function normalizeFileChanges(changes: IDiskFileChange[]): IDiskFileChang
 
 class EventNormalizer {
 
-	private readonly normalized: IDiskFileChange[] = [];
+	private readonly normalized = new Set<IDiskFileChange>();
 	private readonly mapPathToChange = new Map<string, IDiskFileChange>();
 
 	processEvent(event: IDiskFileChange): void {
@@ -64,7 +64,7 @@ class EventNormalizer {
 			// ignore CREATE followed by DELETE in one go
 			if (currentChangeType === FileChangeType.ADDED && newChangeType === FileChangeType.DELETED) {
 				this.mapPathToChange.delete(event.path);
-				this.normalized.splice(this.normalized.indexOf(existingEvent), 1);
+				this.normalized.delete(existingEvent);
 			}
 
 			// flatten DELETE followed by CREATE into CHANGE
@@ -83,7 +83,7 @@ class EventNormalizer {
 
 		// Otherwise store new
 		else {
-			this.normalized.push(event);
+			this.normalized.add(event);
 			this.mapPathToChange.set(event.path, event);
 		}
 	}
@@ -99,7 +99,7 @@ class EventNormalizer {
 		// 1.) split ADD/CHANGE and DELETED events
 		// 2.) sort short deleted paths to the top
 		// 3.) for each DELETE, check if there is a deleted parent and ignore the event in that case
-		return this.normalized.filter(e => {
+		return Array.from(this.normalized).filter(e => {
 			if (e.type !== FileChangeType.DELETED) {
 				addOrChangeEvents.push(e);
 

src/vs/platform/files/test/node/recursiveWatcher.test.ts

@@ -34,6 +34,17 @@ flakySuite('Recursive Watcher', () => {
 				await watcher.instance;
 			}
 		}
+
+		protected override getOptions(watcher: any) {
+			return {
+				...super.getOptions(watcher),
+
+				// required to let tests pass properly. with a smaller value
+				// somehow `fsevents` on macOS seems to report events from
+				// the past so that the event listening will assume wrongly
+				debounceMS: 500
+			};
+		}
 	}
 
 	let testDir: string;