From 775c913de20824d187f677e65845fe8680ecd7f6 Mon Sep 17 00:00:00 2001
From: oobabooga <112222186+oobabooga@users.noreply.github.com>
Date: Mon, 6 Apr 2026 14:13:01 -0700
Subject: [PATCH] Fix crash when truncating prompts with tool call messages

---
 modules/chat.py | 21 ++++++++++++++++-----
 1 file changed, 16 insertions(+), 5 deletions(-)

diff --git a/modules/chat.py b/modules/chat.py
index aeed688d..7e9cce60 100644
--- a/modules/chat.py
+++ b/modules/chat.py
@@ -568,13 +568,24 @@ def generate_chat_prompt(user_input, state, **kwargs):
         encoded_length = get_encoded_length(prompt)
         while len(messages) > 0 and encoded_length > max_length:
 
-            # Remove old message, save system message
             if len(messages) > 2 and messages[0]['role'] == 'system':
-                messages.pop(1)
-
-            # Remove old message when no system message is present
+                pop_idx = 1
             elif len(messages) > 1 and messages[0]['role'] != 'system':
-                messages.pop(0)
+                pop_idx = 0
+            else:
+                pop_idx = None
+
+            if pop_idx is not None:
+                messages.pop(pop_idx)
+
+                # Remove orphaned tool-call/tool-result messages that
+                # would be invalid without their partner.
+                while pop_idx < len(messages):
+                    msg = messages[pop_idx]
+                    if msg.get('role') == 'tool' or (msg.get('role') == 'assistant' and msg.get('tool_calls')):
+                        messages.pop(pop_idx)
+                    else:
+                        break
 
             # Resort to truncating the user input
             else: