sessions: Avoid resolving canceled Changes editor inputs

src/vs/sessions/contrib/changes/browser/sessionChangesEditor.ts

@@ -301,6 +301,9 @@ export class SessionChangesEditor extends AbstractEditorWithViewState<IMultiDiff
 
 	override async setInput(input: SessionChangesEditorInput, options: IMultiDiffEditorOptions | undefined, context: IEditorOpenContext, token: CancellationToken): Promise<void> {
 		await super.setInput(input, options, context, token);
+		if (token.isCancellationRequested) {
+			return;
+		}
 		const sessionResource = this.sessionChangesService.getSessionResource(input.multiDiffSource);
 		this._inputSessionResource.set(sessionResource, undefined);
 		const viewModel = await input.getViewModel();

src/vs/sessions/contrib/changes/test/browser/sessionChangesEditorInput.test.ts

@@ -4,6 +4,7 @@
  *--------------------------------------------------------------------------------------------*/
 
 import assert from 'assert';
+import { CancellationTokenSource } from '../../../../../base/common/cancellation.js';
 import { Emitter, Event, ValueWithChangeEvent } from '../../../../../base/common/event.js';
 import { URI } from '../../../../../base/common/uri.js';
 import { mock } from '../../../../../base/test/common/mock.js';
@@ -112,6 +113,38 @@ suite('SessionChangesEditorInput', () => {
 		});
 	});
 
+	test('does not resolve a canceled editor input', async () => {
+		class TestSessionChangesEditorInput extends SessionChangesEditorInput {
+			viewModelRequested = false;
+
+			override async getViewModel(): Promise<MultiDiffEditorViewModel> {
+				this.viewModelRequested = true;
+				throw new Error('Canceled input must not be resolved');
+			}
+		}
+
+		const instantiationService = workbenchInstantiationService(undefined, disposables);
+		instantiationService.stub(IChangesViewService, {});
+		instantiationService.stub(IAgentWorkbenchLayoutService, {});
+		instantiationService.stub(ISessionChangesService, {});
+		instantiationService.stub(IWorkbenchLayoutService, {
+			onDidChangePartVisibility: Event.None,
+			isVisible: () => true,
+		});
+
+		const editor = disposables.add(instantiationService.createInstance(SessionChangesEditor, new TestEditorGroupView(1)));
+		const input = disposables.add(instantiationService.createInstance(
+			TestSessionChangesEditorInput,
+			URI.parse('changes-multi-diff-source:?{"sessionResource":"agent-host-copilotcli:/session"}'),
+		));
+		const operation = disposables.add(new CancellationTokenSource());
+		operation.cancel();
+
+		await editor.setInput(input, undefined, {}, operation.token);
+
+		assert.deepStrictEqual(input.viewModelRequested, false);
+	});
+
 	test('updates managed Changes editor capabilities with editor area visibility', () => {
 		const instantiationService = disposables.add(new TestInstantiationService());
 		let editorVisible = false;