Fix Schema Nullables (#11092)

* Add missing nullable annotations

* bump API version

src/backend/InvenTree/InvenTree/api_version.py

@@ -1,11 +1,14 @@
 """InvenTree API version information."""
 
 # InvenTree API version
-INVENTREE_API_VERSION = 438
+INVENTREE_API_VERSION = 439
 """Increment this API version number whenever there is a significant change to the API that any clients need to know about."""
 
 INVENTREE_API_TEXT = """
 
+v439 -> 2026-01-09 : https://github.com/inventree/InvenTree/pull/11092
+    - Add missing nullable annotations
+
 v438 -> 2026-01-09 : https://github.com/inventree/InvenTree/pull/11104
     - Adds a simpler / faster health check endpoint at /api/system/health/
 

src/backend/InvenTree/build/serializers.py

@@ -1378,7 +1378,9 @@ class BuildLineSerializer(
     )
 
     allocations = enable_filter(
-        BuildItemSerializer(many=True, read_only=True, build_detail=False),
+        BuildItemSerializer(
+            many=True, read_only=True, allow_null=True, build_detail=False
+        ),
         True,
         prefetch_fields=[
             'allocations',
@@ -1426,6 +1428,7 @@ class BuildLineSerializer(
             source='bom_item',
             many=False,
             read_only=True,
+            allow_null=True,
             pricing=False,
             substitutes=False,
             sub_part_detail=False,
@@ -1455,6 +1458,7 @@ class BuildLineSerializer(
             source='bom_item.sub_part',
             many=False,
             read_only=True,
+            allow_null=True,
             pricing=False,
         ),
         False,

src/backend/InvenTree/common/serializers.py

@@ -808,7 +808,9 @@ class ParameterSerializer(
     )
 
     updated_by_detail = enable_filter(
-        UserSerializer(source='updated_by', read_only=True, many=False),
+        UserSerializer(
+            source='updated_by', read_only=True, allow_null=True, many=False
+        ),
         True,
         prefetch_fields=['updated_by'],
     )