[Fix] Make DeepSeek-V4 reasoning and tool-call streaming parsing chunk-invariant (#34458)

Co-authored-by: hao-cyber <89575785+hao-cyber@users.noreply.github.com> Co-authored-by: Enrico Falco <enrico9034@gmail.com> Co-authored-by: Svyatoslav <85786374+slivanovich@users.noreply.github.com> Co-authored-by: Andreas Hassellof <andreas@ombori.com> Co-authored-by: Leoyzen <leoyzen@gmail.com> Co-authored-by: Chenglun Hu <chenglunhu@gmail.com> Co-authored-by: robellliu-dev <robell.liu@huawei.com> Co-authored-by: Gavin.Zhu <gavin.z@gmicloud.ai> Co-authored-by: Xinyuan Tong <xinyuantong.cs@gmail.com> Co-authored-by: tancheng33 <garrytancheng@gmail.com> Co-authored-by: dineshx29 <dinesh.b.offl@gmail.com> Co-authored-by: Kangyan Zhou <zky314343421@gmail.com>
2026-08-11 20:03:28 -07:00
parent 2be9773a21
commit 5899674504
4 changed files with 383 additions and 48 deletions
@@ -0,0 +1,129 @@
+"""Unit tests for DeepSeekV4Detector DSML streaming — no server, no model loading."""
+
+from unittest.mock import patch
+
+from sglang.srt.entrypoints.openai.protocol import Function, Tool
+from sglang.srt.function_call.deepseekv4_detector import DeepSeekV4Detector
+from sglang.test.ci.ci_register import register_cpu_ci
+from sglang.test.test_utils import CustomTestCase
+
+register_cpu_ci(1.0, "base-a-test-cpu")
+
+DSML = "｜DSML｜"
+
+
+def _wrapped(invoke: str) -> str:
+    return f"<{DSML}tool_calls>\n{invoke}\n</{DSML}tool_calls>"
+
+
+def _invoke(name: str, params: str = "") -> str:
+    return f'<{DSML}invoke name="{name}">\n{params}\n</{DSML}invoke>'
+
+
+def _param(name: str, is_string: str, value: str) -> str:
+    return (
+        f'<{DSML}parameter name="{name}" string="{is_string}">{value}</{DSML}parameter>'
+    )
+
+
+def _weather_call(city: str = "SF") -> str:
+    return _wrapped(_invoke("get_weather", _param("city", "true", city)))
+
+
+class TestDeepSeekV4Streaming(CustomTestCase):
+    def setUp(self):
+        self.tools = [
+            Tool(
+                type="function",
+                function=Function(
+                    name="get_weather",
+                    description="Get weather information",
+                    parameters={
+                        "type": "object",
+                        "properties": {"city": {"type": "string"}},
+                        "required": ["city"],
+                    },
+                ),
+            )
+        ]
+
+    def _feed(self, chunks):
+        """Returns (normal_text, calls) accumulated over the chunks."""
+        detector = DeepSeekV4Detector()
+        normal, calls = "", []
+        for chunk in chunks:
+            result = detector.parse_streaming_increment(chunk, self.tools)
+            normal += result.normal_text
+            calls.extend(result.calls)
+        return normal, calls
+
+    def test_preamble_in_same_delta_as_tool_call(self):
+        """Prose sharing a delta with the tool call must not be dropped, and the
+        streaming and one-shot paths must agree on it."""
+        text = "Let me check.\n" + _weather_call()
+        normal, calls = self._feed([text])
+
+        self.assertEqual([c.name for c in calls if c.name], ["get_weather"])
+        self.assertEqual(
+            normal, DeepSeekV4Detector().detect_and_parse(text, self.tools).normal_text
+        )
+
+    def test_preamble_before_bare_invoke_without_wrapper(self):
+        """The bare `<｜DSML｜invoke …>` form has no tool_calls wrapper to walk
+        back to, so the preamble is computed from the invoke itself."""
+        text = "Checking.\n" + _invoke("get_weather", _param("city", "true", "SF"))
+        normal, calls = self._feed([text])
+
+        self.assertIn("Checking.", normal)
+        self.assertEqual([c.name for c in calls if c.name], ["get_weather"])
+
+    def test_no_dsml_markers_leak_into_normal_text(self):
+        text = "Prose.\n" + _weather_call()
+        normal, _ = self._feed([text[i : i + 4] for i in range(0, len(text), 4)])
+
+        self.assertNotIn(DSML, normal)
+
+    def test_malformed_partial_json_falls_back_to_raw_value(self):
+        """A partial non-string parameter must not escape as MalformedJSON."""
+        detector = DeepSeekV4Detector()
+        result = detector.parse_streaming_increment(
+            f'<{DSML}tool_calls>\n<{DSML}invoke name="get_weather">\n'
+            f'<{DSML}parameter name="city" string="false">{{"a"',
+            self.tools,
+        )
+
+        self.assertEqual([c.name for c in result.calls if c.name], ["get_weather"])
+
+    def test_non_streaming_parses_every_tool_calls_section(self):
+        """A turn with two tool_calls sections must yield both calls."""
+        result = DeepSeekV4Detector().detect_and_parse(
+            f"{_weather_call('SF')}\n{_weather_call('NY')}", self.tools
+        )
+
+        self.assertEqual(len(result.calls), 2)
+
+    def test_parse_error_neither_swallows_nor_duplicates(self):
+        """An unexpected parse error must not empty the turn, and the dropped
+        buffer must not come back on the next delta."""
+        detector = DeepSeekV4Detector()
+
+        with patch.object(
+            DeepSeekV4Detector,
+            "_parse_parameters_from_xml",
+            side_effect=RuntimeError("boom"),
+        ):
+            first = detector.parse_streaming_increment(_weather_call(), self.tools)
+            self.assertEqual(detector._buffer, "")
+            second = detector.parse_streaming_increment(" tail", self.tools)
+
+        self.assertIn("get_weather", first.normal_text)
+        self.assertNotIn("get_weather", second.normal_text)
+        # No half-formed call: the failure can land between a tool's name and its
+        # arguments, so an argument-less named call must not reach the client.
+        self.assertEqual(first.calls, [])
+
+
+if __name__ == "__main__":
+    import unittest
+
+    unittest.main()