From 34a27de85e07e0bd0295943d96be850d0b350a3f Mon Sep 17 00:00:00 2001
From: zhujg007 <371703364@qq.com>
Date: Fri, 10 Apr 2026 20:51:36 +0800
Subject: [PATCH] Fix: Safe char boundary handling for UTF-8 string slicing

---
 crates/openfang-runtime/src/compactor.rs | 9 ++++-----
 1 file changed, 4 insertions(+), 5 deletions(-)

diff --git a/crates/openfang-runtime/src/compactor.rs b/crates/openfang-runtime/src/compactor.rs
index 3186e4f4..de120f21 100644
--- a/crates/openfang-runtime/src/compactor.rs
+++ b/crates/openfang-runtime/src/compactor.rs
@@ -435,11 +435,10 @@ async fn summarize_messages(
         let safe_start = if conversation_text.is_char_boundary(start) {
             start
         } else {
-            conversation_text[start..]
-                .char_indices()
-                .next()
-                .map(|(i, _)| start + i)
-                .unwrap_or(conversation_text.len())
+            // Find the nearest valid character boundary moving upward   
+	        (start..conversation_text.len())
+	            .find(|&i| conversation_text.is_char_boundary(i))
+	            .unwrap_or(conversation_text.len())
         };
         conversation_text = conversation_text[safe_start..].to_string();
     }