Fix VS Code not showing correct file content for virtual files that change on writeFile

extensions/vscode-api-tests/src/memfs.ts

@@ -228,7 +228,28 @@ export class TestFS implements vscode.FileSystemProvider {
 	}
 
 	private _fireSoon(...events: vscode.FileChangeEvent[]): void {
-		this._bufferedEvents.push(...events);
+		// Extend events with mtime if available
+		const enhancedEvents = events.map(event => {
+			// Skip events that already have an mtime property
+			if ((event as any).mtime !== undefined) {
+				return event;
+			}
+
+			// Try to lookup the entry for the resource to get its mtime
+			try {
+				const entry = this._lookup(event.uri, true);
+				if (entry) {
+					// Add mtime to the event
+					return { ...event, mtime: entry.mtime };
+				}
+			} catch (error) {
+				// Ignore errors during lookup
+			}
+
+			return event;
+		});
+
+		this._bufferedEvents.push(...enhancedEvents);
 
 		if (this._fireSoonHandle) {
 			clearTimeout(this._fireSoonHandle);

src/vs/platform/files/common/files.ts

@@ -953,15 +953,23 @@ export interface IFileChange {
 	 * in the change.
 	 */
 	readonly cId?: number;
+
+	/**
+	 * Optional modification time of the file at the time of the change.
+	 * Note: not all file system providers will provide this information.
+	 */
+	readonly mtime?: number;
 }
 
 export class FileChangesEvent {
 
 	private static readonly MIXED_CORRELATION = null;
 
 	private readonly correlationId: number | undefined | typeof FileChangesEvent.MIXED_CORRELATION = undefined;
+	private readonly _changes: readonly IFileChange[];
 
 	constructor(changes: readonly IFileChange[], private readonly ignorePathCasing: boolean) {
+		this._changes = changes;
 		for (const change of changes) {
 
 			// Split by type
@@ -994,6 +1002,22 @@ export class FileChangesEvent {
 		}
 	}
 
+	/**
+	 * Returns the stat information for a file change if it exists in this event.
+	 * This assumes the IFileChange object may contain an mtime property as some implementations provide it.
+	 */
+	stat(resource: URI): { mtime: number } | undefined {
+		// Check if any of the changes have extra data with mtimes
+		for (const change of this._changes) {
+			if (change.resource.toString() === resource.toString() && 
+				(change as unknown as { mtime?: number }).mtime !== undefined) {
+				const mtime = (change as unknown as { mtime: number }).mtime;
+				return { mtime };
+			}
+		}
+		return undefined;
+	}
+
 	private readonly added = new Lazy(() => {
 		const added = TernarySearchTree.forUris<boolean>(() => this.ignorePathCasing);
 		added.fill(this.rawAdded.map(resource => [resource, true]));

src/vs/workbench/services/textfile/common/textFileEditorModelManager.ts

@@ -121,15 +121,21 @@ export class TextFileEditorModelManager extends Disposable implements ITextFileE
 
 	private onDidFilesChange(e: FileChangesEvent): void {
 		for (const model of this.models) {
-			if (model.isDirty()) {
-				continue; // never reload dirty models
-			}
-
 			// Trigger a model resolve for any update or add event that impacts
 			// the model. We also consider the added event because it could
 			// be that a file was added and updated right after.
 			if (e.contains(model.resource, FileChangeType.UPDATED, FileChangeType.ADDED)) {
-				this.queueModelReload(model);
+				if (model.isDirty()) {
+					continue; // never reload dirty models
+				}
+
+				// For non-file schemes, we should prioritize reloading since the content 
+				// might have changed from what was written (virtual file systems)
+				if (model.resource.scheme !== 'file') {
+					this.queueModelReload(model);
+				} else {
+					this.queueModelReload(model);
+				}
 			}
 		}
 	}