fix #50479

src/vs/base/browser/ui/progressbar/progressbar.ts

@@ -164,16 +164,31 @@ export class ProgressBar {
 	}
 
 	/**
-	 * Tells the progress bar that an amount of work has been completed.
+	 * Tells the progress bar that an increment of work has been completed.
 	 */
 	public worked(value: number): ProgressBar {
-		assert.ok(!isNaN(this.totalWork), 'Total work not set');
+		value = Number(value);
+		assert.ok(!isNaN(value), 'Value is not a number');
+		value = Math.max(1, value);
+
+		return this.doSetWorked(this.workedVal + value);
+	}
 
+	/**
+	 * Tells the progress bar the total amount of work that has been completed.
+	 */
+	public setWorked(value: number): ProgressBar {
 		value = Number(value);
 		assert.ok(!isNaN(value), 'Value is not a number');
 		value = Math.max(1, value);
 
-		this.workedVal += value;
+		return this.doSetWorked(value);
+	}
+
+	private doSetWorked(value: number): ProgressBar {
+		assert.ok(!isNaN(this.totalWork), 'Total work not set');
+
+		this.workedVal = value;
 		this.workedVal = Math.min(this.totalWork, this.workedVal);
 
 		if (this.element.hasClass(css_infinite)) {

src/vs/base/test/browser/progressBar.test.ts

@@ -24,7 +24,8 @@ suite('ProgressBar', () => {
 		assert(bar.infinite());
 		assert(bar.total(100));
 		assert(bar.worked(50));
-		assert(bar.worked(50));
+		assert(bar.setWorked(70));
+		assert(bar.worked(30));
 		assert(bar.done());
 
 		bar.dispose();

src/vs/workbench/browser/parts/notifications/notificationsViewer.ts

@@ -474,7 +474,7 @@ export class NotificationTemplateRenderer {
 			}
 
 			if (typeof state.worked === 'number') {
-				this.template.progress.worked(state.worked).show();
+				this.template.progress.setWorked(state.worked).show();
 			}
 		}
 

src/vs/workbench/common/notifications.ts

@@ -314,7 +314,11 @@ export class NotificationViewItemProgress implements INotificationViewItemProgre
 	}
 
 	public worked(value: number): void {
-		this._state.worked = value;
+		if (typeof this._state.worked === 'number') {
+			this._state.worked += value;
+		} else {
+			this._state.worked = value;
+		}
 
 		this._state.infinite = void 0;
 		this._state.done = void 0;