add indexmissing and indexempty support

Author: tylerhutcherson

redisvl/query/filter.py

@@ -73,6 +73,24 @@ def _set_value(
         self._value = val
         self._operator = operator
 
+    def is_missing(self) -> "FilterExpression":
+        """Create a filter expression for documents missing this field.
+
+        Returns:
+            FilterExpression: A filter expression that matches documents where the field is missing.
+
+        .. code-block:: python
+
+            from redisvl.query.filter import Tag, Text, Num, Geo, Timestamp
+
+            f = Tag("brand").is_missing()
+            f = Text("title").is_missing()
+            f = Num("price").is_missing()
+            f = Geo("location").is_missing()
+            f = Timestamp("created_at").is_missing()
+        """
+        return FilterExpression(f"ismissing(@{self._field})")
+
 
 def check_operator_misuse(func: Callable) -> Callable:
     @wraps(func)

redisvl/utils/utils.py

@@ -45,7 +45,8 @@ def serialize_item(item):
         else:
             return item
 
-    serialized_data = model.model_dump(exclude_none=True)
+    # Use exclude_defaults=False to preserve all field attributes including new ones
+    serialized_data = model.model_dump(exclude_none=True, exclude_defaults=False)
     for key, value in serialized_data.items():
         serialized_data[key] = serialize_item(value)
     return serialized_data