Adds 'variant_of' filter back into Part API

InvenTree/InvenTree/api_version.py

@@ -4,11 +4,14 @@ InvenTree API version information
 
 
 # InvenTree API version
-INVENTREE_API_VERSION = 40
+INVENTREE_API_VERSION = 41
 
 """
 Increment this API version number whenever there is a significant change to the API that any clients need to know about
 
+v41 -> 2022-04-26
+    - Fixes 'variant_of' filter for Part list endpoint
+
 v40 -> 2022-04-19
     - Adds ability to filter StockItem list by "tracked" parameter
         - This checks the serial number or batch code fields

InvenTree/part/api.py

@@ -1175,6 +1175,18 @@ class PartList(generics.ListCreateAPIView):
             except (ValueError, Part.DoesNotExist):
                 pass
 
+        # Filter by 'variant_of'
+        # Note that this is subtly different from 'ancestor' filter (above)
+        variant_of = params.get('variant_of', None)
+
+        if variant_of is not None:
+            try:
+                template = Part.objects.get(pk=variant_of)
+                variants = template.get_children()
+                queryset = queryset.filter(pk__in=[v.pk for v in variants])
+            except (ValueError, Part.DoesNotExist):
+                pass
+
         # Filter only parts which are in the "BOM" for a given part
         in_bom_for = params.get('in_bom_for', None)