watcher - ignore uncorrelated events when in correlation mode (microsoft#196530)

Author: bpasero

src/vs/workbench/api/browser/mainThreadFileSystemEventService.ts

@@ -214,7 +214,6 @@ export class MainThreadFileSystemEventService implements MainThreadFileSystemEve
 
 	async $watch(extensionId: string, session: number, resource: UriComponents, unvalidatedOpts: IWatchOptions): Promise<void> {
 		const uri = URI.revive(resource);
-		const correlate = Array.isArray(unvalidatedOpts?.excludes) && unvalidatedOpts.excludes.length > 0; // TODO@bpasero for now only correlate proposed new file system watcher API with excludes
 
 		const opts: IWatchOptions = {
 			...unvalidatedOpts
@@ -235,7 +234,8 @@ export class MainThreadFileSystemEventService implements MainThreadFileSystemEve
 			}
 		}
 
-		// Correlated file watching is taken as is
+		// Correlated file watching is taken as is (for now we only opt into correlating with proposed new file system watcher API with excludes)
+		const correlate = Array.isArray(unvalidatedOpts?.excludes) && unvalidatedOpts.excludes.length > 0;
 		if (correlate) {
 			this._logService.trace(`MainThreadFileSystemEventService#$watch(): request to start watching correlated (extension: ${extensionId}, path: ${uri.toString(true)}, recursive: ${opts.recursive}, session: ${session})`);
 

src/vs/workbench/api/common/extHostFileSystemEventService.ts

@@ -70,9 +70,18 @@ class FileSystemWatcher implements vscode.FileSystemWatcher {
 		// https://github.com/microsoft/vscode/issues/3025
 		const excludeOutOfWorkspaceEvents = typeof globPattern === 'string';
 
+		// 1.84.x introduces new proposed API for a watcher to set exclude
+		// rules. When this is provided, we turn the file watcher into correlation
+		// mode and ignore any event that does not match the correlation ID.
+		const excludeUncorrelatedEvents = Array.isArray(options?.excludes) && options.excludes.length > 0;
+
 		const subscription = dispatcher(events => {
 			if (typeof events.session === 'number' && events.session !== this.session) {
-				return; // ignore events from other file watchers
+				return; // ignore events from other file watchers that are in correlation mode
+			}
+
+			if (excludeUncorrelatedEvents && typeof events.session === 'undefined') {
+				return; // ignore events from other non-correlating file watcher when we are in correlation mode
 			}
 
 			if (!options?.ignoreCreateEvents) {