From 8eb235ab512528de4c55200c09e2cbc3159a94ba Mon Sep 17 00:00:00 2001
From: Lawrence Wu <lawrence.wu@harmonic.fun>
Date: Thu, 9 Apr 2026 11:14:15 -0700
Subject: [PATCH] fix: do not strip whitespace from GLM tool call values
 (#20543)

Co-authored-by: Kangyan-Zhou <zky314343421@gmail.com>
---
 .../srt/function_call/glm47_moe_detector.py   |  1 -
 .../srt/function_call/glm4_moe_detector.py    |  1 -
 .../test_function_call_parser.py              | 66 +++++++++++++++++++
 3 files changed, 66 insertions(+), 2 deletions(-)

diff --git a/python/sglang/srt/function_call/glm47_moe_detector.py b/python/sglang/srt/function_call/glm47_moe_detector.py
index 0b25b11eb..9bc11d770 100644
--- a/python/sglang/srt/function_call/glm47_moe_detector.py
+++ b/python/sglang/srt/function_call/glm47_moe_detector.py
@@ -759,7 +759,6 @@ class Glm47MoeDetector(BaseFormatDetector):
         arguments = {}
         for arg_key, arg_value in pairs:
             arg_key = arg_key.strip()
-            arg_value = arg_value.strip()
             arg_type = get_argument_type(func_name, arg_key, tools)
             parsed_value, is_good_json = parse_arguments(arg_value, arg_type)
 
diff --git a/python/sglang/srt/function_call/glm4_moe_detector.py b/python/sglang/srt/function_call/glm4_moe_detector.py
index 0761e24e7..36992b3fe 100644
--- a/python/sglang/srt/function_call/glm4_moe_detector.py
+++ b/python/sglang/srt/function_call/glm4_moe_detector.py
@@ -613,7 +613,6 @@ class Glm4MoeDetector(BaseFormatDetector):
         arguments = {}
         for arg_key, arg_value in pairs:
             arg_key = arg_key.strip()
-            arg_value = arg_value.strip()
             arg_type = get_argument_type(func_name, arg_key, tools)
             parsed_value, is_good_json = parse_arguments(arg_value, arg_type)
 
diff --git a/test/registered/unit/function_call/test_function_call_parser.py b/test/registered/unit/function_call/test_function_call_parser.py
index 01aa99904..f0974d45e 100644
--- a/test/registered/unit/function_call/test_function_call_parser.py
+++ b/test/registered/unit/function_call/test_function_call_parser.py
@@ -2276,6 +2276,39 @@ class TestGlm4MoeDetector(unittest.TestCase):
             self.assertIsInstance(result, StreamingParseResult)
             self.assertEqual(result.calls, [])
 
+    def test_whitespace_preserved_in_arg_values(self):
+        """Test that leading/trailing whitespace in arg values is not stripped."""
+        tools_with_string = [
+            Tool(
+                type="function",
+                function=Function(
+                    name="apply_diff",
+                    description="Apply a diff",
+                    parameters={
+                        "type": "object",
+                        "properties": {
+                            "old_string": {"type": "string"},
+                            "new_string": {"type": "string"},
+                        },
+                        "required": ["old_string", "new_string"],
+                    },
+                ),
+            )
+        ]
+        text = (
+            "<tool_call>apply_diff\n"
+            "<arg_key>old_string</arg_key>\n"
+            "<arg_value>    indented code</arg_value>\n"
+            "<arg_key>new_string</arg_key>\n"
+            "<arg_value>        also indented</arg_value>\n"
+            "</tool_call>"
+        )
+        result = self.detector.detect_and_parse(text, tools_with_string)
+        self.assertEqual(len(result.calls), 1)
+        params = json.loads(result.calls[0].parameters)
+        self.assertEqual(params["old_string"], "    indented code")
+        self.assertEqual(params["new_string"], "        also indented")
+
 
 class TestGlm47MoeDetector(unittest.TestCase):
     def setUp(self):
@@ -2552,6 +2585,39 @@ class TestGlm47MoeDetector(unittest.TestCase):
         )
         check_single_todos(result, expected_output)
 
+    def test_whitespace_preserved_in_arg_values(self):
+        """Test that leading/trailing whitespace in arg values is not stripped."""
+        tools_with_string = [
+            Tool(
+                type="function",
+                function=Function(
+                    name="apply_diff",
+                    description="Apply a diff",
+                    parameters={
+                        "type": "object",
+                        "properties": {
+                            "old_string": {"type": "string"},
+                            "new_string": {"type": "string"},
+                        },
+                        "required": ["old_string", "new_string"],
+                    },
+                ),
+            )
+        ]
+        text = (
+            "<tool_call>apply_diff"
+            "<arg_key>old_string</arg_key>"
+            "<arg_value>    indented code</arg_value>"
+            "<arg_key>new_string</arg_key>"
+            "<arg_value>        also indented</arg_value>"
+            "</tool_call>"
+        )
+        result = self.detector.detect_and_parse(text, tools_with_string)
+        self.assertEqual(len(result.calls), 1)
+        params = json.loads(result.calls[0].parameters)
+        self.assertEqual(params["old_string"], "    indented code")
+        self.assertEqual(params["new_string"], "        also indented")
+
 
 class TestJsonArrayParser(unittest.TestCase):
     def setUp(self):