Make circular reference detection aware of parent type to avoid false-positives when multiple fields pointing to the same COT are present

Author: bctiemann

netbox_custom_objects/models.py

@@ -1041,8 +1041,8 @@ def _check_recursion(self):
             return  # Not a custom object type, no recursion possible
 
         # Check for circular references by traversing the dependency chain
-        visited = {self.custom_object_type.id}
-        if self._has_circular_reference(related_custom_object_type, visited):
+        visited = {(self.custom_object_type.id, None)}
+        if self._has_circular_reference(related_custom_object_type, self.custom_object_type, visited):
             raise ValidationError(
                 {
                     "related_object_type": _(
@@ -1052,7 +1052,7 @@ def _check_recursion(self):
                 }
             )
 
-    def _has_circular_reference(self, custom_object_type, visited):
+    def _has_circular_reference(self, custom_object_type, parent_custom_object_type, visited):
         """
         Recursively check if there's a circular reference by following the dependency chain.
 
@@ -1063,12 +1063,13 @@ def _has_circular_reference(self, custom_object_type, visited):
         Returns:
             bool: True if a circular reference is detected, False otherwise
         """
-        # If we've already visited this type, we have a cycle
-        if custom_object_type.id in visited:
-            return True
+        # If we've already visited this type (and it's from a different parent), we have a cycle
+        for visited_type_id, visited_parent_id in visited:
+            if visited_type_id == custom_object_type.id and visited_parent_id != parent_custom_object_type.id:
+                return True
 
         # Add this type to visited set
-        visited.add(custom_object_type.id)
+        visited.add((custom_object_type.id, parent_custom_object_type.id))
 
         # Check all object and multiobject fields in this custom object type
         for field in custom_object_type.fields.filter(
@@ -1087,7 +1088,7 @@ def _has_circular_reference(self, custom_object_type, visited):
                 continue
 
             # Recursively check this dependency
-            if self._has_circular_reference(next_custom_object_type, visited):
+            if self._has_circular_reference(next_custom_object_type, custom_object_type, visited):
                 return True
 
         return False