fix: handle unserializable objects in serialize_defaults (#1527)

Co-authored-by: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: ionmincu

packages/uipath-core/pyproject.toml

@@ -1,6 +1,6 @@
 [project]
 name = "uipath-core"
-version = "0.5.9"
+version = "0.5.10"
 description = "UiPath Core abstractions"
 readme = { file = "README.md", content-type = "text/markdown" }
 requires-python = ">=3.11"

packages/uipath-core/src/uipath/core/serialization/json.py

@@ -67,6 +67,15 @@ def serialize_defaults(
         >>> serialize_json(user)
         '{"name": "Alice", "created_at": "2024-01-01T12:00:00"}'
     """
+    try:
+        return _serialize_defaults_inner(obj)
+    except Exception:
+        return str(obj)
+
+
+def _serialize_defaults_inner(
+    obj: Any,
+) -> dict[str, Any] | list[Any] | str | int | float | bool | None:
     # Handle Pydantic BaseModel instances
     if hasattr(obj, "model_dump") and not isinstance(obj, type):
         return obj.model_dump(exclude_none=True, mode="json")
@@ -97,7 +106,7 @@ def serialize_defaults(
 
     # Handle enums - recursively serialize the value
     if isinstance(obj, Enum):
-        return serialize_defaults(obj.value)
+        return _serialize_defaults_inner(obj.value)
 
     # Handle sets and tuples
     if isinstance(obj, (set, tuple)):

packages/uipath-core/tests/serialization/test_json.py

@@ -636,3 +636,24 @@ def __str__(self) -> str:
 
         # Seventh sublist: Booleans and None
         assert parsed[6] == [True, False, None]
+
+    def test_dataclass_with_unpicklable_field_falls_back_to_str(self) -> None:
+        """Test dataclass containing unpicklable objects (e.g. SimpleQueue) falls back to str().
+
+        dataclasses.asdict() uses copy.deepcopy internally, which fails on objects
+        that cannot be pickled (like _queue.SimpleQueue found in httpx clients).
+        The serializer should gracefully fall back to str() instead of raising.
+        """
+        import queue
+
+        @dataclass
+        class DataclassWithQueue:
+            name: str
+            internal: Any
+
+        obj = DataclassWithQueue(name="test", internal=queue.SimpleQueue())
+        data = {"obj": obj}
+        result = serialize_json(data)
+        parsed = json.loads(result)
+        assert isinstance(parsed["obj"], str)
+        assert "DataclassWithQueue" in parsed["obj"]