Serializer: filter None fields, to avoid conflicts with nix module system

pkgs/clan-cli/clan_cli/api/serde.py

@@ -68,7 +68,8 @@ def dataclass_to_dict(obj: Any, *, use_alias: bool = True) -> Any:
                     field.metadata.get("alias", field.name) if use_alias else field.name
                 ): _to_dict(getattr(obj, field.name))
                 for field in fields(obj)
-                if not field.name.startswith("_")  # type: ignore
+                if not field.name.startswith("_")
+                and getattr(obj, field.name) is not None  # type: ignore
             }
         elif isinstance(obj, list | tuple):
             return [_to_dict(item) for item in obj]

pkgs/clan-cli/tests/test_serializers.py

@@ -104,3 +104,23 @@ def test_dataclass_to_dict_defaults() -> None:
         "foo": {"home": {"a": "b"}, "work": ["a", "b"]},
     }
     assert dataclass_to_dict(real_person) == expected
+
+
+def test_filters_null_fields() -> None:
+    @dataclass
+    class Foo:
+        home: str | None = None
+        work: str | None = None
+
+    # None fields are filtered out
+    instance = Foo()
+
+    assert instance.home is None
+    assert dataclass_to_dict(instance) == {}
+
+    # fields that are set are not filtered
+    instance = Foo(home="home")
+
+    assert instance.home == "home"
+    assert instance.work is None
+    assert dataclass_to_dict(instance) == {"home": "home"}