Update tiktoken.py

tiktoken.py

@@ -173,12 +173,17 @@ class TiktokenTokenizerWrapper(PreTrainedTokenizer):
         Pinning default Chat ML template in case defaults change.
         """
         template = (
+            "{% set loop_messages = messages %}"
+            "{% set system_message = '' %}"
             "{% if messages[0]['role'] == 'system' %}"
-            "{% set loop_messages = messages[1:] %}"  # Extract system message if it's present
+            "{% set loop_messages = messages[1:] %}"
             "{% set system_message = messages[0]['content'] %}"
+            "{{'<|im_start|>system\n' + system_message}}"
             "{% elif USE_DEFAULT_PROMPT == true and not 'system' in messages[0]['role']%}"
-            "{% set loop_messages = messages %}"  # Extract system message if it's present
+            "{% set loop_messages = messages %}"
             "{% set system_message = 'DEFAULT_SYSTEM_PROMPT' %}"
+            '{% endif %}'
+            "{% if not (system_message == '') %}"
             "{{'<|im_start|>system\n' + system_message}}"
             '{% endif %}'
             '{% for message in loop_messages %}'