fix(python): Options that are None are also None in python (#212)

* Options that are None are also None in python

* Update test to check attributes on event

* chore: add changeset

* fix(core): add custom Serialize implementation for AttributeValue

This should fix `null` attributes serializing to unit instead of none.

---------

Co-authored-by: Oleksii Shmalko <[email protected]>
Co-authored-by: Oleksii Shmalko <[email protected]>
Co-authored-by: Leo Romanovsky <[email protected]>

Author: 3 people

.changeset/cyan-socks-fold.md

@@ -0,0 +1,8 @@
+---
+"eppo_core": patch
+"python-sdk": patch
+"ruby-sdk": patch
+"rust-sdk": patch
+---
+
+Fix `AttributeValue` serialization, so `Null` attributes are properly serialized as None instead of unit value.

eppo_core/src/attributes.rs

@@ -35,7 +35,7 @@ pub type Attributes = HashMap<Str, AttributeValue>;
 #[derive(Debug, Clone, PartialEq, PartialOrd, derive_more::From, Serialize, Deserialize)]
 #[from(NumericAttribute, CategoricalAttribute, f64, bool, Str, String, &str, Arc<str>, Arc<String>, Cow<'_, str>)]
 pub struct AttributeValue(AttributeValueImpl);
-#[derive(Debug, Clone, PartialEq, PartialOrd, derive_more::From, Serialize, Deserialize)]
+#[derive(Debug, Clone, PartialEq, PartialOrd, derive_more::From, Deserialize)]
 #[serde(untagged)]
 enum AttributeValueImpl {
     #[from(NumericAttribute, f64)]
@@ -46,6 +46,23 @@ enum AttributeValueImpl {
     Null,
 }
 
+impl serde::Serialize for AttributeValueImpl {
+    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
+    where
+        S: serde::Serializer,
+    {
+        match self {
+            AttributeValueImpl::Numeric(numeric_attribute) => {
+                numeric_attribute.serialize(serializer)
+            }
+            AttributeValueImpl::Categorical(categorical_attribute) => {
+                categorical_attribute.serialize(serializer)
+            }
+            AttributeValueImpl::Null => serializer.serialize_none(),
+        }
+    }
+}
+
 impl AttributeValue {
     /// Create a numeric attribute.
     #[inline]

eppo_core/src/pyo3.rs

@@ -25,7 +25,7 @@ impl<T: TryToPyObject> TryToPyObject for Option<T> {
     fn try_to_pyobject(&self, py: Python) -> PyResult<PyObject> {
         match self {
             Some(it) => it.try_to_pyobject(py),
-            None => Ok(().to_object(py)),
+            None => Ok(py.None()),
         }
     }
 }

python-sdk/tests/test_assignment_logger.py

@@ -41,11 +41,13 @@ def log_assignment(self, assignment_event: Dict):
 
     client = init("ufc", assignment_logger=MyAssignmentLogger())
     result = client.get_string_assignment(
-        "regex-flag", "alice", {"email": "[email protected]"}, "default"
+        "regex-flag", "alice", {"email": "[email protected]", "empty": None}, "default"
     )
     assert result == "partial-example"
 
     assert event["allocation"] == "partial-example"
     assert event["featureFlag"] == "regex-flag"
     assert event["experiment"] == "regex-flag-partial-example"
     assert event["metaData"]["sdkName"] == "python"
+    assert event["subjectAttributes"]["email"] == "[email protected]"
+    assert event["subjectAttributes"]["empty"] is None