Truncate long chat completions inputs (#5439)

modules/chat.py

@@ -166,18 +166,53 @@ def generate_chat_prompt(user_input, state, **kwargs):
         prompt = remove_extra_bos(prompt)
         return prompt
 
-    prompt = make_prompt(messages)
-
     # Handle truncation
     max_length = get_max_prompt_length(state)
-    while len(messages) > 0 and get_encoded_length(prompt) > max_length:
-        # Try to save the system message
-        if len(messages) > 1 and messages[0]['role'] == 'system':
+    prompt = make_prompt(messages)
+    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)
-        else:
+
+        # Remove old message when no system message is present
+        elif len(messages) > 1 and messages[0]['role'] != 'system':
             messages.pop(0)
 
+        # Resort to truncating the user input
+        else:
+
+            user_message = messages[-1]['content']
+
+            # Bisect the truncation point
+            left, right = 0, len(user_message) - 1
+
+            while right - left > 1:
+                mid = (left + right) // 2
+
+                messages[-1]['content'] = user_message[mid:]
+                prompt = make_prompt(messages)
+                encoded_length = get_encoded_length(prompt)
+
+                if encoded_length <= max_length:
+                    right = mid
+                else:
+                    left = mid
+
+            messages[-1]['content'] = user_message[right:]
+            prompt = make_prompt(messages)
+            encoded_length = get_encoded_length(prompt)
+            if encoded_length > max_length:
+                logger.error(f"Failed to build the chat prompt. The input is too long for the available context length.\n\nTruncation length: {state['truncation_length']}\nmax_new_tokens: {state['max_new_tokens']} (is it too high?)\nAvailable context length: {max_length}\n")
+                raise ValueError
+            else:
+                logger.warning(f"The input has been truncated. Context length: {state['truncation_length']}, max_new_tokens: {state['max_new_tokens']}.")
+                break
+
         prompt = make_prompt(messages)
+        encoded_length = get_encoded_length(prompt)
 
     if also_return_rows:
         return prompt, [message['content'] for message in messages]

modules/text_generation.py

@@ -50,6 +50,11 @@ def _generate_reply(question, state, stopping_strings=None, is_chat=False, escap
         else:
             generate_func = generate_reply_HF
 
+    if generate_func != generate_reply_HF and shared.args.verbose:
+        logger.info("PROMPT=")
+        print(question)
+        print()
+
     # Prepare the input
     original_question = question
     if not is_chat:
@@ -65,10 +70,6 @@ def _generate_reply(question, state, stopping_strings=None, is_chat=False, escap
         if type(st) is list and len(st) > 0:
             all_stop_strings += st
 
-    if shared.args.verbose:
-        logger.info("PROMPT=")
-        print(question)
-
     shared.stop_everything = False
     clear_torch_cache()
     seed = set_manual_seed(state['seed'])
@@ -355,6 +356,10 @@ def generate_reply_HF(question, original_question, seed, state, stopping_strings
         pprint.PrettyPrinter(indent=4, sort_dicts=False).pprint(filtered_params)
         print()
 
+        logger.info("PROMPT=")
+        print(decode(input_ids[0], skip_special_tokens=False))
+        print()
+
     t0 = time.time()
     try:
         if not is_chat and not shared.is_seq2seq: