fix(tool call): Fix tool_index in PythonicDetector and issues with mixed output in non-streaming (#6678)

python/sglang/srt/function_call/base_format_detector.py

@@ -72,7 +72,7 @@ class BaseFormatDetector(ABC):
         action = json.loads(text)
         return StreamingParseResult(calls=self.parse_base_json(action, tools))
 
-    def ends_with_partial_token(self, buffer: str, bot_token: str) -> int:
+    def _ends_with_partial_token(self, buffer: str, bot_token: str) -> int:
         """
         Check if buffer ends with a partial bot_token.
         Return the length of the partial bot_token.
@@ -108,7 +108,7 @@ class BaseFormatDetector(ABC):
         current_text = self._buffer
         if not (self.bot_token in current_text or current_text.startswith("{")):
             # Only clear buffer if we're sure no tool call is starting
-            if not self.ends_with_partial_token(self._buffer, self.bot_token):
+            if not self._ends_with_partial_token(self._buffer, self.bot_token):
                 normal_text = self._buffer
                 self._buffer = ""
                 if self.eot_token in normal_text:

python/sglang/srt/function_call/pythonic_detector.py

@@ -33,46 +33,67 @@ class PythonicDetector(BaseFormatDetector):
         )
 
     def has_tool_call(self, text: str) -> bool:
-        return bool(self.tool_call_regex.match(text.strip()))
+        return bool(self.tool_call_regex.search(text.strip()))
 
     def detect_and_parse(self, text: str, tools: List[Tool]) -> StreamingParseResult:
         # Try parsing the text as a Python list of function calls
         text = text.strip()
-        if not (text.startswith("[") and text.endswith("]")):
-            # Not a pythonic tool call format
+
+        match = self.tool_call_regex.search(text)
+        if match is None:
             return StreamingParseResult(normal_text=text, calls=[])
+
+        # Extract the tool call part and any text before/after it
+        tool_call_start = match.start()
+        tool_call_end = match.end()
+
+        normal_text_before = text[:tool_call_start] if tool_call_start > 0 else ""
+        tool_call_text = text[tool_call_start:tool_call_end]
+        normal_text_after = text[tool_call_end:] if tool_call_end < len(text) else ""
+
+        # Combine normal text
+        normal_text = normal_text_before + normal_text_after
+
         try:
-            module = ast.parse(text)
+            module = ast.parse(tool_call_text)
             parsed = getattr(module.body[0], "value", None)
             if not (
                 isinstance(parsed, ast.List)
                 and all(isinstance(e, ast.Call) for e in parsed.elts)
             ):
-                return StreamingParseResult(normal_text=text, calls=[])
+                return StreamingParseResult(normal_text=normal_text, calls=[])
+
             calls = []
             tool_indices = {
                 tool.function.name: i
                 for i, tool in enumerate(tools)
                 if tool.function.name
             }
-            for call in parsed.elts:
+            for call_index, call in enumerate(parsed.elts):
                 if not isinstance(call.func, ast.Name):
                     continue
                 function_name = call.func.id
+                # Validate that the function exists in the tools
+                if function_name not in tool_indices:
+                    logger.warning(
+                        f"Model attempted to call undefined function: {function_name}"
+                    )
+                    continue
                 arguments = {}
                 for keyword in call.keywords:
                     arguments[keyword.arg] = self._get_parameter_value(keyword.value)
                 calls.append(
                     ToolCallItem(
-                        tool_index=tool_indices.get(function_name, -1),
+                        tool_index=call_index,  # Use the call index in the response, not tool position
                         name=function_name,
                         parameters=json.dumps(arguments, ensure_ascii=False),
                     )
                 )
-            return StreamingParseResult(normal_text="", calls=calls)
+
+            return StreamingParseResult(normal_text=normal_text, calls=calls)
         except Exception:
             logger.exception("Error in pythonic tool call parsing.")
-            return StreamingParseResult(normal_text=text, calls=[])
+            return StreamingParseResult(normal_text=normal_text, calls=[])
 
     def _find_matching_bracket(self, buffer: str, start: int) -> int:
         """

python/sglang/srt/function_call/qwen25_detector.py

@@ -86,7 +86,7 @@ class Qwen25Detector(BaseFormatDetector):
                 result.normal_text = cleaned_text
             else:
                 # Check if buffer might contain partial end token at the end
-                partial_match_len = self.ends_with_partial_token(
+                partial_match_len = self._ends_with_partial_token(
                     self._normal_text_buffer, end_token_without_newline
                 )