From 415a36a195f34b3fcde7e08f0d17f3dea1ffb327 Mon Sep 17 00:00:00 2001
From: Silvio Junior <silviojr.dcc@gmail.com>
Date: Tue, 26 Aug 2025 00:10:53 -0400
Subject: [PATCH] Do not call nextSpeakerCheck if there was an error processing
 the stream.  (#7048)

Co-authored-by: christine betts <chrstn@uw.edu>
Co-authored-by: Antonio Scandurra <me@as-cii.com>
Co-authored-by: Arya Gummadi <aryagummadi@google.com>
Co-authored-by: gemini-code-assist[bot] <176961590+gemini-code-assist[bot]@users.noreply.github.com>
Co-authored-by: Shreya Keshive <skeshive@gmail.com>
Co-authored-by: Abhi <43648792+abhipatel12@users.noreply.github.com>
Co-authored-by: shishu314 <shishu_1998@yahoo.com>
Co-authored-by: Shi Shu <shii@google.com>
Co-authored-by: Steven <steventohme59@gmail.com>
Co-authored-by: Pascal Birchler <pascalb@google.com>
Co-authored-by: N. Taylor Mullen <ntaylormullen@google.com>
---
 packages/core/src/core/client.test.ts | 85 +++++++++++++++++++++++++++
 packages/core/src/core/client.ts      |  3 +
 2 files changed, 88 insertions(+)

diff --git a/packages/core/src/core/client.test.ts b/packages/core/src/core/client.test.ts
index 9fdd7e06..c858876e 100644
--- a/packages/core/src/core/client.test.ts
+++ b/packages/core/src/core/client.test.ts
@@ -51,6 +51,8 @@ vi.mock('./turn', () => {
     GeminiEventType: {
       MaxSessionTurns: 'MaxSessionTurns',
       ChatCompressed: 'ChatCompressed',
+      Error: 'error',
+      Content: 'content',
     },
   };
 });
@@ -1887,6 +1889,89 @@ ${JSON.stringify(
         expect(JSON.stringify(finalCall)).toContain('fileC.ts');
       });
     });
+
+    it('should not call checkNextSpeaker when turn.run() yields an error', async () => {
+      // Arrange
+      const { checkNextSpeaker } = await import(
+        '../utils/nextSpeakerChecker.js'
+      );
+      const mockCheckNextSpeaker = vi.mocked(checkNextSpeaker);
+
+      const mockStream = (async function* () {
+        yield {
+          type: GeminiEventType.Error,
+          value: { error: { message: 'test error' } },
+        };
+      })();
+      mockTurnRunFn.mockReturnValue(mockStream);
+
+      const mockChat: Partial<GeminiChat> = {
+        addHistory: vi.fn(),
+        getHistory: vi.fn().mockReturnValue([]),
+      };
+      client['chat'] = mockChat as GeminiChat;
+
+      const mockGenerator: Partial<ContentGenerator> = {
+        countTokens: vi.fn().mockResolvedValue({ totalTokens: 0 }),
+        generateContent: mockGenerateContentFn,
+      };
+      client['contentGenerator'] = mockGenerator as ContentGenerator;
+
+      // Act
+      const stream = client.sendMessageStream(
+        [{ text: 'Hi' }],
+        new AbortController().signal,
+        'prompt-id-error',
+      );
+      for await (const _ of stream) {
+        // consume stream
+      }
+
+      // Assert
+      expect(mockCheckNextSpeaker).not.toHaveBeenCalled();
+    });
+
+    it('should not call checkNextSpeaker when turn.run() yields a value then an error', async () => {
+      // Arrange
+      const { checkNextSpeaker } = await import(
+        '../utils/nextSpeakerChecker.js'
+      );
+      const mockCheckNextSpeaker = vi.mocked(checkNextSpeaker);
+
+      const mockStream = (async function* () {
+        yield { type: GeminiEventType.Content, value: 'some content' };
+        yield {
+          type: GeminiEventType.Error,
+          value: { error: { message: 'test error' } },
+        };
+      })();
+      mockTurnRunFn.mockReturnValue(mockStream);
+
+      const mockChat: Partial<GeminiChat> = {
+        addHistory: vi.fn(),
+        getHistory: vi.fn().mockReturnValue([]),
+      };
+      client['chat'] = mockChat as GeminiChat;
+
+      const mockGenerator: Partial<ContentGenerator> = {
+        countTokens: vi.fn().mockResolvedValue({ totalTokens: 0 }),
+        generateContent: mockGenerateContentFn,
+      };
+      client['contentGenerator'] = mockGenerator as ContentGenerator;
+
+      // Act
+      const stream = client.sendMessageStream(
+        [{ text: 'Hi' }],
+        new AbortController().signal,
+        'prompt-id-error',
+      );
+      for await (const _ of stream) {
+        // consume stream
+      }
+
+      // Assert
+      expect(mockCheckNextSpeaker).not.toHaveBeenCalled();
+    });
   });
 
   describe('generateContent', () => {
diff --git a/packages/core/src/core/client.ts b/packages/core/src/core/client.ts
index d6a30c94..bc1054a2 100644
--- a/packages/core/src/core/client.ts
+++ b/packages/core/src/core/client.ts
@@ -513,6 +513,9 @@ export class GeminiClient {
         return turn;
       }
       yield event;
+      if (event.type === GeminiEventType.Error) {
+        return turn;
+      }
     }
     if (!turn.pendingToolCalls.length && signal && !signal.aborted) {
       // Check if model was switched during the call (likely due to quota error)