From d6bff5051ea86dbc529b66df33016fb04054b62a Mon Sep 17 00:00:00 2001
From: Mohammad Hijjawi <mohammad.hijjawi1997@gmail.com>
Date: Sat, 17 Oct 2026 23:28:52 +0100
Subject: [PATCH] fix: Serialize UUID and TimeUuid entity keys

An entity whose join key is a Uuid or TimeUuid could be applied, but
materializing it failed in serialize_entity_key with "Value type not
supported for feast feature store", so its features never reached the
online store and could not be served.

Encode uuid_val and time_uuid_val as their UTF-8 string with the UUID and
TIME_UUID value type tags, and decode them back in deserialize_entity_key.

Signed-off-by: Mohammad Hijjawi <mohammad.hijjawi1997@gmail.com>
---
 sdk/python/feast/infra/key_encoding_utils.py  |  8 ++++
 .../unit/infra/test_key_encoding_utils.py     | 40 +++++++++++++++++++
 2 files changed, 48 insertions(+)

diff --git a/sdk/python/feast/infra/key_encoding_utils.py b/sdk/python/feast/infra/key_encoding_utils.py
index 10a9934ad6a..6378a12d434 100644
--- a/sdk/python/feast/infra/key_encoding_utils.py
+++ b/sdk/python/feast/infra/key_encoding_utils.py
@@ -24,6 +24,10 @@ def _serialize_val(
         return struct.pack("<q", v.int64_val), ValueType.INT64
     elif value_type == "unix_timestamp_val":
         return struct.pack("<q", v.unix_timestamp_val), ValueType.UNIX_TIMESTAMP
+    elif value_type == "uuid_val":
+        return v.uuid_val.encode("utf8"), ValueType.UUID
+    elif value_type == "time_uuid_val":
+        return v.time_uuid_val.encode("utf8"), ValueType.TIME_UUID
     else:
         raise ValueError(f"Value type not supported for feast feature store: {v}")
 
@@ -43,6 +47,10 @@ def _deserialize_value(value_type, value_bytes) -> ValueProto:
     elif value_type == ValueType.UNIX_TIMESTAMP:
         value = struct.unpack("<q", value_bytes)[0]
         return ValueProto(unix_timestamp_val=value)
+    elif value_type == ValueType.UUID:
+        return ValueProto(uuid_val=value_bytes.decode("utf-8"))
+    elif value_type == ValueType.TIME_UUID:
+        return ValueProto(time_uuid_val=value_bytes.decode("utf-8"))
     else:
         raise ValueError(f"Unsupported value type: {value_type}")
 
diff --git a/sdk/python/tests/unit/infra/test_key_encoding_utils.py b/sdk/python/tests/unit/infra/test_key_encoding_utils.py
index 604368a7242..069aae3ca56 100644
--- a/sdk/python/tests/unit/infra/test_key_encoding_utils.py
+++ b/sdk/python/tests/unit/infra/test_key_encoding_utils.py
@@ -1,3 +1,5 @@
+import pytest
+
 from feast.infra.key_encoding_utils import (
     _deserialize_value,
     _serialize_val,
@@ -131,6 +133,44 @@ def test_serialize_deserialize_unix_timestamp_entity():
     assert deserialized_key.entity_values[0].unix_timestamp_val == 1758823656
 
 
+@pytest.mark.parametrize(
+    "value_field, value_type, value",
+    [
+        ("uuid_val", ValueType.UUID, "a8098c1a-f86e-41da-bd1a-00112444be1e"),
+        (
+            "time_uuid_val",
+            ValueType.TIME_UUID,
+            "c232ab00-9414-11ec-b3c8-9f6bdeced846",
+        ),
+    ],
+    ids=["uuid", "time_uuid"],
+)
+def test_serialize_deserialize_uuid_entity(value_field, value_type, value):
+    serialized_value, serialized_type = _serialize_val(
+        value_field, ValueProto(**{value_field: value})
+    )
+    assert serialized_type == value_type
+    assert serialized_value == value.encode("utf8")
+
+    entity_key_proto = EntityKeyProto(
+        join_keys=["session_id"],
+        entity_values=[ValueProto(**{value_field: value})],
+    )
+
+    serialized_key = serialize_entity_key(
+        entity_key_proto,
+        entity_key_serialization_version=3,
+    )
+
+    deserialized_key = deserialize_entity_key(
+        serialized_key,
+        entity_key_serialization_version=3,
+    )
+
+    assert deserialized_key == entity_key_proto
+    assert getattr(deserialized_key.entity_values[0], value_field) == value
+
+
 def test_reserialize_entity_v2_key_to_v3():
     entity_key_proto_v2 = EntityKeyProto(
         join_keys=["user"],