From 71649db3b065a5e355b536362bab048e931c745b Mon Sep 17 00:00:00 2001
From: buua436 <sz_buua@foxmail.com>
Date: Fri, 5 Jun 2026 13:21:26 +0800
Subject: [PATCH] fix: prevent duplicated post-think text (#15651)

### What problem does this PR solve?
This fixes duplicated post-think text in streamed chat responses. When
the model emits text immediately after `</think>`, the stream state now
advances its cursor correctly so the same visible prefix is not emitted
twice.

### Type of change
- [x] Bug Fix (non-breaking change which fixes an issue)
---
 api/db/services/dialog_service.py | 1 +
 1 file changed, 1 insertion(+)

diff --git a/api/db/services/dialog_service.py b/api/db/services/dialog_service.py
index 0662e8d48f..8d282baa77 100644
--- a/api/db/services/dialog_service.py
+++ b/api/db/services/dialog_service.py
@@ -1478,6 +1478,7 @@ def _next_think_delta(state: _ThinkStreamState) -> str:
         remainder = delta_ans[len("</think>") :]
         if remainder:
             state.post_think_text = remainder
+        state.last_idx = len(full_text)
         return "</think>"
 
     state.last_idx = len(full_text)