fix: prevent category field from being silently dropped by omit_defaults

- Change TypeDef.category to Union[AtlanTypeCategory, UnsetType] = UNSET
  so the base class no longer makes it required (allows absent from JSON)
- Remove hardcoded category defaults from all subclasses (EnumDef, StructDef,
  AtlanTagDef, EntityDef, RelationshipDef, CustomMetadataDef) to prevent
  omit_defaults=True from dropping the field when its value equals the default
- Add __post_init__ to each subclass to unconditionally set the correct
  AtlanTypeCategory, matching the pattern used by generated asset classes
- Update test assertions from `is None` to `is msgspec.UNSET` for absent fields

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Author: cmgrote

pyatlan_v9/model/typedef.py

@@ -233,7 +233,7 @@ def _get_all_qualified_names(client: AtlanClient, asset_type: str) -> Set[str]:
 class TypeDef(msgspec.Struct, kw_only=True, rename="camel", omit_defaults=True):
     """Base type definition."""
 
-    category: AtlanTypeCategory
+    category: Union[AtlanTypeCategory, msgspec.UnsetType] = msgspec.UNSET
     """Type of the type definition."""
 
     create_time: Union[int, None, msgspec.UnsetType] = msgspec.UNSET
@@ -327,9 +327,6 @@ def extend_elements(current: List[str], new: List[str]) -> List[str]:
                     unique_elements.add(element)
             return extended_list
 
-    category: AtlanTypeCategory = AtlanTypeCategory.ENUM
-    """Type category for enumeration definitions."""
-
     element_defs: Union[List[EnumDef.ElementDef], msgspec.UnsetType] = msgspec.UNSET
     """Valid values for the enumeration."""
 
@@ -339,6 +336,9 @@ def extend_elements(current: List[str], new: List[str]) -> List[str]:
     service_type: Union[str, None, msgspec.UnsetType] = msgspec.UNSET
     """Internal use only."""
 
+    def __post_init__(self) -> None:
+        self.category = AtlanTypeCategory.ENUM
+
     @staticmethod
     def creator(name: str, values: List[str]) -> EnumDef:
         """
@@ -1225,15 +1225,15 @@ class RelationshipAttributeDef(AttributeDef, kw_only=True):
 class StructDef(TypeDef, kw_only=True):
     """Struct type definition."""
 
-    category: AtlanTypeCategory = AtlanTypeCategory.STRUCT
-    """Type category for struct definitions."""
-
     attribute_defs: Union[List[AttributeDef], None, msgspec.UnsetType] = msgspec.UNSET
     """List of attributes that should be available in the type definition."""
 
     service_type: Union[str, None, msgspec.UnsetType] = msgspec.UNSET
     """Internal use only."""
 
+    def __post_init__(self) -> None:
+        self.category = AtlanTypeCategory.STRUCT
+
 
 # =============================================================================
 # ATLAN TAG DEFINITION (CLASSIFICATION)
@@ -1246,9 +1246,6 @@ class AtlanTagDef(TypeDef, kw_only=True):
     attribute_defs: Union[List[AttributeDef], None, msgspec.UnsetType] = msgspec.UNSET
     """Unused."""
 
-    category: AtlanTypeCategory = AtlanTypeCategory.CLASSIFICATION
-    """Type category for classification definitions."""
-
     display_name: Union[str, None, msgspec.UnsetType] = msgspec.UNSET
     """Name used for display purposes (in user interfaces)."""
 
@@ -1272,6 +1269,9 @@ class AtlanTagDef(TypeDef, kw_only=True):
     )
     """TBC"""
 
+    def __post_init__(self) -> None:
+        self.category = AtlanTypeCategory.CLASSIFICATION
+
     @staticmethod
     def creator(
         name: str,
@@ -1337,9 +1337,6 @@ class EntityDef(TypeDef, kw_only=True):
     ] = msgspec.UNSET
     """Unused."""
 
-    category: AtlanTypeCategory = AtlanTypeCategory.ENTITY
-    """Type category for entity definitions."""
-
     relationship_attribute_defs: Union[
         List[RelationshipAttributeDef], msgspec.UnsetType
     ] = msgspec.UNSET
@@ -1354,6 +1351,9 @@ class EntityDef(TypeDef, kw_only=True):
     super_types: Union[List[str], msgspec.UnsetType] = msgspec.UNSET
     """List of super-types that this type definition extends."""
 
+    def __post_init__(self) -> None:
+        self.category = AtlanTypeCategory.ENTITY
+
     @property
     def reserved_type(self) -> bool:
         """Whether this entity definition is a reserved (built-in) type."""
@@ -1408,9 +1408,6 @@ class RelationshipDef(TypeDef, kw_only=True):
     attribute_defs: Union[List[AttributeDef], msgspec.UnsetType] = msgspec.UNSET
     """Unused."""
 
-    category: AtlanTypeCategory = AtlanTypeCategory.RELATIONSHIP
-    """Type category for relationship definitions."""
-
     end_def1: Union[RelationshipEndDef, None, msgspec.UnsetType] = msgspec.UNSET
     """Definition for the first endpoint of the relationship."""
 
@@ -1440,6 +1437,9 @@ class RelationshipDef(TypeDef, kw_only=True):
     super_types: Union[List[str], msgspec.UnsetType] = msgspec.UNSET
     """List of super-types that this relationship type extends."""
 
+    def __post_init__(self) -> None:
+        self.category = AtlanTypeCategory.RELATIONSHIP
+
 
 # =============================================================================
 # CUSTOM METADATA DEFINITION
@@ -1524,15 +1524,15 @@ def with_logo_from_icon(
     attribute_defs: Union[List[AttributeDef], msgspec.UnsetType] = msgspec.UNSET
     """List of custom attributes defined within the custom metadata."""
 
-    category: AtlanTypeCategory = AtlanTypeCategory.CUSTOM_METADATA
-    """Type category for custom metadata definitions."""
-
     display_name: Union[str, None, msgspec.UnsetType] = msgspec.UNSET
     """Name used for display purposes (in user interfaces)."""
 
     options: Union[CustomMetadataDef.Options, None, msgspec.UnsetType] = msgspec.UNSET
     """Optional properties of the type definition."""
 
+    def __post_init__(self) -> None:
+        self.category = AtlanTypeCategory.CUSTOM_METADATA
+
     @staticmethod
     def creator(
         display_name: str, description: Optional[str] = None

tests_v9/unit/aio/test_custom_metadata.py

@@ -2,6 +2,7 @@
 # Copyright 2025 Atlan Pte. Ltd.
 from unittest.mock import AsyncMock, patch
 
+import msgspec
 import pytest
 
 from pyatlan_v9.client.aio.atlan import AsyncAtlanClient
@@ -553,4 +554,6 @@ async def async_generator():
         # Cannot be multi-valued
         assert options.multi_value_select is False
         # Should not have custom_type set (that's for SQL, URL, etc.)
-        assert not hasattr(options, "custom_type") or options.custom_type is None
+        assert (
+            not hasattr(options, "custom_type") or options.custom_type is msgspec.UNSET
+        )

tests_v9/unit/test_typedef_model.py

@@ -96,7 +96,7 @@ def check_property(property_name: str):
         if key in source:
             assert value == source[key]
         else:
-            assert value is None
+            assert value is msgspec.UNSET
 
     check_property("create_time")
     check_property("created_by")
@@ -120,7 +120,7 @@ def check_attribute(model: object, attribute_name: str, source: dict):
     else:
         # Since "options" are now initialized with a default factory
         if attribute_name != "options":
-            assert getattr(model, attribute_name) is None
+            assert getattr(model, attribute_name) is msgspec.UNSET
 
 
 def check_has_attributes(type_def: TypeDef, type_def_json: dict):
@@ -588,4 +588,6 @@ def test_rich_text_options_configuration(self, client: AtlanClient):
         # Cannot be multi-valued
         assert options.multi_value_select is False
         # Should not have custom_type set (that's for SQL, URL, etc.)
-        assert not hasattr(options, "custom_type") or options.custom_type is None
+        assert (
+            not hasattr(options, "custom_type") or options.custom_type is msgspec.UNSET
+        )