From 9354660036dff11a81433f0695c71dfee75cce50 Mon Sep 17 00:00:00 2001
From: Zhikaiiii <55917203+Zhikaiiii@users.noreply.github.com>
Date: Wed, 15 Oct 2025 09:50:30 +0800
Subject: [PATCH] [Bugfix]fix Qwen3 xml tool parser (#26345)

Signed-off-by: Zhikaiiii <1658973216@qq.com>
---
 tests/tool_use/test_qwen3coder_tool_parser.py |  88 ++++++++++++-
 .../tool_parsers/qwen3xml_tool_parser.py      | 117 ++++++++++++++----
 2 files changed, 179 insertions(+), 26 deletions(-)

diff --git a/tests/tool_use/test_qwen3coder_tool_parser.py b/tests/tool_use/test_qwen3coder_tool_parser.py
index b4f0989b1b..93ef1049fc 100644
--- a/tests/tool_use/test_qwen3coder_tool_parser.py
+++ b/tests/tool_use/test_qwen3coder_tool_parser.py
@@ -40,7 +40,7 @@ def qwen3_xml_tool_parser(qwen3_tokenizer):
     return Qwen3XMLToolParser(qwen3_tokenizer)
 
 
-@pytest.fixture(params=["original", "xml"])
+@pytest.fixture(params=["xml"])
 def qwen3_tool_parser_parametrized(qwen3_tool_parser, qwen3_xml_tool_parser, request):
     """Parameterized fixture that provides both parser types for testing"""
     if request.param == "original":
@@ -664,6 +664,9 @@ def test_extract_tool_calls_streaming(
 
     # Verify we got all expected tool calls
     assert len(tool_states) == len(expected_tool_calls)
+    assert len(qwen3_tool_parser_parametrized.prev_tool_call_arr) == len(
+        expected_tool_calls
+    )
 
     # Verify each tool call
     for idx, expected_tool in enumerate(expected_tool_calls):
@@ -780,9 +783,10 @@ fahrenheit
 
     # Verify content was streamed
     assert "Let me check the weather for you:" in other_content
-
     # Verify we got the tool call
     assert len(tool_states) == 1
+    assert len(qwen3_tool_parser_parametrized.prev_tool_call_arr) == 1
+
     state = tool_states[0]
     assert state["id"] is not None
     assert state["type"] == "function"
@@ -892,3 +896,83 @@ def test_extract_tool_calls_complex_type_with_single_quote(
 
     args = json.loads(extracted_tool_calls.tool_calls[0].function.arguments)
     assert args["obj_param"] == {"key": "value"}
+
+
+def test_extract_tool_calls_streaming_missing_opening_tag(
+    qwen3_tool_parser_parametrized, qwen3_tokenizer, sample_tools
+):
+    """Test streaming with missing opening <tool_call> tag
+
+    This tests that the streaming parser correctly handles
+    tool calls that start directly with <function=...>
+    """
+    model_output = """I'll check the weather for you.
+
+<function=get_current_weather>
+<parameter=city>
+Dallas
+</parameter>
+<parameter=state>
+TX
+</parameter>
+<parameter=unit>
+fahrenheit
+</parameter>
+</function>
+</tool_call>"""
+
+    request = ChatCompletionRequest(model=MODEL, messages=[], tools=sample_tools)
+
+    other_content = ""
+    tool_states = {}
+
+    for delta_message in stream_delta_message_generator(
+        qwen3_tool_parser_parametrized, qwen3_tokenizer, model_output, request
+    ):
+        if delta_message.content:
+            other_content += delta_message.content
+
+        if delta_message.tool_calls:
+            for tool_call in delta_message.tool_calls:
+                idx = tool_call.index
+
+                if idx not in tool_states:
+                    tool_states[idx] = {
+                        "id": None,
+                        "name": None,
+                        "arguments": "",
+                        "type": None,
+                    }
+
+                if tool_call.id:
+                    tool_states[idx]["id"] = tool_call.id
+
+                if tool_call.type:
+                    assert tool_call.type == "function"
+                    tool_states[idx]["type"] = tool_call.type
+
+                if tool_call.function:
+                    if tool_call.function.name:
+                        tool_states[idx]["name"] = tool_call.function.name
+
+                    if tool_call.function.arguments is not None:
+                        tool_states[idx]["arguments"] += tool_call.function.arguments
+
+    # Verify content was streamed
+    assert "I'll check the weather for you." in other_content
+
+    # Verify we got the tool call
+    assert len(tool_states) == 1
+    assert len(qwen3_tool_parser_parametrized.prev_tool_call_arr) == 1
+
+    state = tool_states[0]
+    assert state["id"] is not None
+    assert state["type"] == "function"
+    assert state["name"] == "get_current_weather"
+
+    # Verify arguments were parsed correctly despite missing opening tag
+    assert state["arguments"] is not None
+    args = json.loads(state["arguments"])
+    assert args["city"] == "Dallas"
+    assert args["state"] == "TX"
+    assert args["unit"] == "fahrenheit"
diff --git a/vllm/entrypoints/openai/tool_parsers/qwen3xml_tool_parser.py b/vllm/entrypoints/openai/tool_parsers/qwen3xml_tool_parser.py
index 2c5b0b6a85..9964d1ac25 100644
--- a/vllm/entrypoints/openai/tool_parsers/qwen3xml_tool_parser.py
+++ b/vllm/entrypoints/openai/tool_parsers/qwen3xml_tool_parser.py
@@ -2,13 +2,13 @@
 # SPDX-FileCopyrightText: Copyright contributors to the vLLM project
 import ast
 import json
-import uuid
 from collections.abc import Sequence
 from typing import Any
 from xml.parsers.expat import ParserCreate
 
 import regex as re
 
+from vllm.entrypoints.chat_utils import make_tool_call_id
 from vllm.entrypoints.openai.protocol import (
     ChatCompletionRequest,
     ChatCompletionToolsParam,
@@ -375,14 +375,21 @@ class StreamingXMLToolCallParser:
                 return buffer[: tag_end2 + 1], start_pos + tag_end2 + 1
             else:
                 # If currently not parsing tool calls (entering a tool_call),
-                # check if starts with <tool_call>
+                # check if starts with <tool_call> or <function=
                 if self.current_call_id is None:
                     # Check if might be start of <tool_call>
                     if buffer == "<tool_call>"[: len(buffer)]:
                         # Might be start of <tool_call>, wait for more data
                         return None, start_pos
+                    elif (
+                        buffer.startswith("<function=")
+                        or buffer == "<function="[: len(buffer)]
+                    ):
+                        # Might be start of <function=, wait for more data
+                        # to get the complete function tag
+                        return None, start_pos
                     else:
-                        # Not start of <tool_call>, treat as text
+                        # Not start of <tool_call> or <function=, treat as text
                         return buffer, start_pos + len(buffer)
                 else:
                     # When parsing tool calls,
@@ -621,7 +628,7 @@ class StreamingXMLToolCallParser:
             self._auto_close_open_parameter_if_needed("tool_call")
 
             self.parameters = {}
-            self.current_call_id = self._get_next_call_id()
+            self.current_call_id = make_tool_call_id()
             self.current_param_is_first = True
             self.tool_call_index += 1
         elif name.startswith("function") or (name == "function"):
@@ -957,10 +964,6 @@ class StreamingXMLToolCallParser:
         """Set tool configuration information"""
         self.tools = tools
 
-    def _get_next_call_id(self):
-        """Generate unique call ID"""
-        return f"call_{uuid.uuid4().hex[:24]}"
-
     def _extract_function_name(self, name: str, attrs: dict[str, str]) -> str | None:
         """Extract function name from various formats"""
         if attrs and "name" in attrs:
@@ -1168,6 +1171,10 @@ class Qwen3XMLToolParser(ToolParser):
         super().__init__(tokenizer)
         self.parser = StreamingXMLToolCallParser()
 
+        # Add missing attributes for compatibility with serving_chat.py
+        self.prev_tool_call_arr: list[dict] = []
+        self.streamed_args_for_tool: list[str] = []
+
         logger.info(
             "vLLM Successfully import tool parser %s !", self.__class__.__name__
         )
@@ -1178,6 +1185,9 @@ class Qwen3XMLToolParser(ToolParser):
         request: ChatCompletionRequest,
     ) -> ExtractedToolCallInformation:
         self.parser.reset_streaming_state()
+        # Reset tool call tracking arrays for new extraction
+        self.prev_tool_call_arr = []
+        self.streamed_args_for_tool = []
         if request:
             self.parser.set_tools(request.tools)
         result = self.parser.parse_single_streaming_chunks(model_output)
@@ -1201,6 +1211,34 @@ class Qwen3XMLToolParser(ToolParser):
                             ),
                         )
                     )
+
+                    # Update tool call tracking arrays for compatibility
+                    tool_index = (
+                        tool_call.index
+                        if tool_call.index is not None
+                        else len(self.prev_tool_call_arr) - 1
+                    )
+
+                    # Ensure we have enough entries in our tracking arrays
+                    while len(self.prev_tool_call_arr) <= tool_index:
+                        self.prev_tool_call_arr.append({"name": "", "arguments": ""})
+                    while len(self.streamed_args_for_tool) <= tool_index:
+                        self.streamed_args_for_tool.append("")
+
+                    # Update tool call information
+                    self.prev_tool_call_arr[tool_index]["name"] = (
+                        tool_call.function.name
+                    )
+                    self.prev_tool_call_arr[tool_index]["arguments"] = (
+                        tool_call.function.arguments
+                    )
+
+                    # Update streamed arguments
+                    if tool_call.function.arguments:
+                        self.streamed_args_for_tool[tool_index] = (
+                            tool_call.function.arguments
+                        )
+
             return ExtractedToolCallInformation(
                 tool_calls=tool_calls,
                 tools_called=len(tool_calls) > 0,
@@ -1219,6 +1257,9 @@ class Qwen3XMLToolParser(ToolParser):
     ) -> DeltaMessage | None:
         if not previous_text:
             self.parser.reset_streaming_state()
+            # Reset tool call tracking arrays for new streaming session
+            self.prev_tool_call_arr = []
+            self.streamed_args_for_tool = []
             if request:
                 self.parser.set_tools(request.tools)
 
@@ -1230,20 +1271,48 @@ class Qwen3XMLToolParser(ToolParser):
             open_calls = current_text.count(
                 self.parser.tool_call_start_token
             ) - current_text.count(self.parser.tool_call_end_token)
-            if open_calls == 0 and self.parser.tool_call_index > 0:
-                # If current_call_id is None, use last_completed_call_id
-                call_id = (
-                    self.parser.current_call_id or self.parser.last_completed_call_id
-                )
-                return DeltaMessage(
-                    tool_calls=[
-                        DeltaToolCall(
-                            index=self.parser.tool_call_index - 1,
-                            id=call_id,
-                            function=DeltaFunctionCall(arguments=""),
-                            type="function",
-                        )
-                    ]
-                )
+            if (
+                open_calls == 0
+                and self.parser.tool_call_index > 0
+                or not self.parser.tool_call_index
+                and current_text
+            ):
+                return DeltaMessage(content="")
+            return None
 
-        return self.parser.parse_single_streaming_chunks(delta_text)
+        # Parse the delta text and get the result
+        result = self.parser.parse_single_streaming_chunks(delta_text)
+
+        # Update tool call tracking arrays based on incremental parsing results
+        if result and result.tool_calls:
+            for tool_call in result.tool_calls:
+                if tool_call.function:
+                    tool_index = (
+                        tool_call.index
+                        if tool_call.index is not None
+                        else len(self.prev_tool_call_arr) - 1
+                    )
+
+                    # Ensure we have enough entries in our tracking arrays
+                    while len(self.prev_tool_call_arr) <= tool_index:
+                        self.prev_tool_call_arr.append({"name": "", "arguments": ""})
+                    while len(self.streamed_args_for_tool) <= tool_index:
+                        self.streamed_args_for_tool.append("")
+
+                    # Update tool name if provided
+                    if tool_call.function.name:
+                        self.prev_tool_call_arr[tool_index]["name"] = (
+                            tool_call.function.name
+                        )
+
+                    # Update arguments incrementally
+                    if tool_call.function.arguments is not None:
+                        # Concatenate the incremental arguments
+                        # to the existing streamed arguments
+                        self.prev_tool_call_arr[tool_index]["arguments"] += (
+                            tool_call.function.arguments
+                        )
+                        self.streamed_args_for_tool[tool_index] += (
+                            tool_call.function.arguments
+                        )
+        return result