Fix interaction with SKIP_CHILDREN_ON_DELETE.

Author: Kircheneer

diffsync/helpers.py

@@ -361,11 +361,14 @@ def sync_diff_element(self, element: DiffElement, parent_model: Optional["DiffSy
             dst_model = None
 
         natural_deletion_order = False
+        skip_children = False
+        # Set up flag booleans
         if dst_model:
             natural_deletion_order = bool(dst_model.model_flags & DiffSyncModelFlags.NATURAL_DELETION_ORDER)
+            skip_children = bool(dst_model.model_flags & DiffSyncModelFlags.SKIP_CHILDREN_ON_DELETE)
 
         changed = False
-        if natural_deletion_order and self.action == DiffSyncActions.DELETE:
+        if natural_deletion_order and self.action == DiffSyncActions.DELETE and not skip_children:
             for child in element.get_children():
                 changed |= self.sync_diff_element(child, parent_model=dst_model)
 
@@ -384,7 +387,6 @@ def sync_diff_element(self, element: DiffElement, parent_model: Optional["DiffSy
             if parent_model:
                 parent_model.remove_child(dst_model)
 
-            skip_children = bool(dst_model.model_flags & DiffSyncModelFlags.SKIP_CHILDREN_ON_DELETE)
             self.dst_diffsync.remove(dst_model, remove_children=skip_children)
 
             if skip_children:

tests/unit/test_diffsync.py

@@ -973,6 +973,7 @@ class NoDeleteInterfaceDiffSync(BackendA):
     extra_models.load()
     extra_device = extra_models.device(name="nyc-spine3", site_name="nyc", role="spine")
     extra_device.model_flags |= DiffSyncModelFlags.SKIP_CHILDREN_ON_DELETE
+    extra_device.model_flags |= DiffSyncModelFlags.NATURAL_DELETION_ORDER
     extra_models.get(extra_models.site, "nyc").add_child(extra_device)
     extra_models.add(extra_device)
     extra_interface = extra_models.interface(name="eth0", device_name="nyc-spine3")