From 2e0e60b4db2613a47632edcbff458ebee7fa85ee Mon Sep 17 00:00:00 2001
From: Shangwei Chen <109785802+Somezak1@users.noreply.github.com>
Date: Mon, 18 Sep 2023 09:17:52 +0800
Subject: [PATCH] Fixed character overlap issue when api streaming output
 (#2431)

---
 fastchat/serve/openai_api_server.py | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/fastchat/serve/openai_api_server.py b/fastchat/serve/openai_api_server.py
index 02e8481f4..7b596de64 100644
--- a/fastchat/serve/openai_api_server.py
+++ b/fastchat/serve/openai_api_server.py
@@ -435,7 +435,7 @@ async def chat_completion_stream_generator(
                 return
             decoded_unicode = content["text"].replace("\ufffd", "")
             delta_text = decoded_unicode[len(previous_text) :]
-            previous_text = decoded_unicode
+            previous_text = decoded_unicode if len(decoded_unicode) > len(previous_text) else previous_text
 
             if len(delta_text) == 0:
                 delta_text = None
@@ -554,7 +554,7 @@ async def generate_completion_stream_generator(
                     return
                 decoded_unicode = content["text"].replace("\ufffd", "")
                 delta_text = decoded_unicode[len(previous_text) :]
-                previous_text = decoded_unicode
+                previous_text = decoded_unicode if len(decoded_unicode) > len(previous_text) else previous_text
                 # todo: index is not apparent
                 choice_data = CompletionResponseStreamChoice(
                     index=i,