fix(core): handle AbortError thrown during processTurn (#21296)

Co-authored-by: Gaurav <39389231+gsquared94@users.noreply.github.com>

packages/core/src/core/client.test.ts

@@ -728,6 +728,23 @@ describe('Gemini Client (client.ts)', () => {
       );
     });
 
+    it('yields UserCancelled when processTurn throws AbortError', async () => {
+      const abortError = new Error('Aborted');
+      abortError.name = 'AbortError';
+      vi.spyOn(client['loopDetector'], 'turnStarted').mockRejectedValueOnce(
+        abortError,
+      );
+
+      const stream = client.sendMessageStream(
+        [{ text: 'Hi' }],
+        new AbortController().signal,
+        'prompt-id-abort-error',
+      );
+      const events = await fromAsync(stream);
+
+      expect(events).toEqual([{ type: GeminiEventType.UserCancelled }]);
+    });
+
     it.each([
       {
         compressionStatus:

packages/core/src/core/client.ts

@@ -34,7 +34,7 @@ import {
   type RetryAvailabilityContext,
 } from '../utils/retry.js';
 import type { ValidationRequiredError } from '../utils/googleQuotaErrors.js';
-import { getErrorMessage } from '../utils/errors.js';
+import { getErrorMessage, isAbortError } from '../utils/errors.js';
 import { tokenLimit } from './tokenLimits.js';
 import type {
   ChatRecordingService,
@@ -957,6 +957,12 @@ export class GeminiClient {
           );
         }
       }
+    } catch (error) {
+      if (signal?.aborted || isAbortError(error)) {
+        yield { type: GeminiEventType.UserCancelled };
+        return turn;
+      }
+      throw error;
     } finally {
       const hookState = this.hookStateMap.get(prompt_id);
       if (hookState) {