fix: Update json features supported by xGrammar (#30390)

Signed-off-by: Johannes Flommersfeld <johannes.flommersfeld@tngtech.com>
Signed-off-by: Johannes F <johannesflommersfeld@users.noreply.github.com>
Co-authored-by: Johannes Flommersfeld <johannes.flommersfeld@tngtech.com>
Co-authored-by: gemini-code-assist[bot] <176961590+gemini-code-assist[bot]@users.noreply.github.com>

tests/v1/entrypoints/conftest.py

@@ -76,6 +76,8 @@ def sample_json_schema():
         },
         "required": ["name", "age", "skills", "grade", "email", "work_history"],
         "additionalProperties": False,
+        "minProperties": 1,
+        "maxProperties": 10,
     }
 
 
@@ -96,6 +98,9 @@ def unsupported_json_schema():
         },
         "required": ["score", "tags"],
         "additionalProperties": False,
+        "patternProperties": {
+            "^score$": {"type": "integer"},
+        },
     }
 
 

tests/v1/structured_output/test_utils.py

@@ -44,8 +44,6 @@ def unsupported_array_schemas():
 @pytest.fixture
 def unsupported_object_schemas():
     return [
-        {"type": "object", "minProperties": 1},
-        {"type": "object", "maxProperties": 5},
         {"type": "object", "propertyNames": {"pattern": "^[a-z]+$"}},
         {"type": "object", "patternProperties": {"^S": {"type": "string"}}},
     ]
@@ -79,6 +77,8 @@ def supported_schema():
                 },
             },
         },
+        "minProperties": 1,
+        "maxProperties": 100,
     }
 
 

vllm/v1/structured_output/backend_xgrammar.py

@@ -268,13 +268,7 @@ def has_xgrammar_unsupported_json_features(schema: dict[str, Any]) -> bool:
 
         # Unsupported keywords for objects
         if obj.get("type") == "object" and any(
-            key in obj
-            for key in (
-                "minProperties",
-                "maxProperties",
-                "propertyNames",
-                "patternProperties",
-            )
+            key in obj for key in ("patternProperties", "propertyNames")
         ):
             return True