fix: Null value compatibility for unit timestamp list value type (feast-dev#4378)

Signed-off-by: Bhargav Dodla <bdodla@expediagroup.com>
Co-authored-by: Bhargav Dodla <bdodla@expediagroup.com>

Author: EXPEbdodla

sdk/python/feast/type_map.py

@@ -396,13 +396,18 @@ def _python_value_to_proto_value(
                         raise _type_err(item, valid_types[0])
 
             if feast_value_type == ValueType.UNIX_TIMESTAMP_LIST:
-                int_timestamps_lists = (
-                    _python_datetime_to_int_timestamp(value) for value in values
-                )
                 return [
-                    # ProtoValue does actually accept `np.int_` but the typing complains.
-                    ProtoValue(unix_timestamp_list_val=Int64List(val=ts))  # type: ignore
-                    for ts in int_timestamps_lists
+                    (
+                        # ProtoValue does actually accept `np.int_` but the typing complains.
+                        ProtoValue(
+                            unix_timestamp_list_val=Int64List(
+                                val=_python_datetime_to_int_timestamp(value)  # type: ignore
+                            )
+                        )
+                        if value is not None
+                        else ProtoValue()
+                    )
+                    for value in values
                 ]
             if feast_value_type == ValueType.BOOL_LIST:
                 # ProtoValue does not support conversion of np.bool_ so we need to convert it to support np.bool_.

sdk/python/tests/unit/test_type_map.py

@@ -60,7 +60,14 @@ def test_python_values_to_proto_values_bool(values):
         (np.array([b'["a","b","c"]']), ValueType.STRING_LIST, ["a", "b", "c"]),
         (np.array([b"[true,false]"]), ValueType.BOOL_LIST, [True, False]),
         (np.array([b"[1,0]"]), ValueType.BOOL_LIST, [True, False]),
+        (np.array([None]), ValueType.INT32_LIST, None),
+        (np.array([None]), ValueType.INT64_LIST, None),
+        (np.array([None]), ValueType.FLOAT_LIST, None),
+        (np.array([None]), ValueType.DOUBLE_LIST, None),
+        (np.array([None]), ValueType.BOOL_LIST, None),
+        (np.array([None]), ValueType.BYTES_LIST, None),
         (np.array([None]), ValueType.STRING_LIST, None),
+        (np.array([None]), ValueType.UNIX_TIMESTAMP_LIST, None),
         ([b"[1,2,3]"], ValueType.INT64_LIST, [1, 2, 3]),
         ([b"[1,2,3]"], ValueType.INT32_LIST, [1, 2, 3]),
         ([b"[1.5,2.5,3.5]"], ValueType.FLOAT_LIST, [1.5, 2.5, 3.5]),