fix: reassign unique imported relations atomically

netbox_export/__init__.py

@@ -7,7 +7,7 @@ class NetBoxExportConfig(PluginConfig):
     name = "netbox_export"
     verbose_name = "NetBox-Export"
     description = "Portable ZIP export and import for tenants and locations"
-    version = "0.3.5"
+    version = "0.3.6"
     author = "NetBox Export contributors"
     base_url = "netbox-export"
     min_version = "4.6.0"

netbox_export/services/exporter.py

@@ -39,7 +39,7 @@ def export_scope(
         "created_at": datetime.now(UTC).isoformat(),
         "source_instance": str(InstanceIdentity.local_id()),
         "source_netbox_version": getattr(getattr(settings, "RELEASE", None), "version", "4.6"),
-        "plugin_version": "0.3.5",
+        "plugin_version": "0.3.6",
         "scope": {
             "type": scope_type,
             "source_pk": str(scope_id),

netbox_export/services/importer.py

@@ -20,6 +20,7 @@ from .plugin_compat import (
     PluginCompatibility,
     is_tenant_relation,
     relation_required_before_save,
+    relation_should_be_deferred,
 )
 from .references import MISSING_REFERENCE, ReferenceResolver
 
@@ -256,6 +257,8 @@ def _field_kwargs(model, record, resolver, *, tenant_required: bool):
                     missing_required.append(name)
             elif value is None and tenant_relation and tenant_required:
                 continue
+            elif value is not None and relation_should_be_deferred(field):
+                unresolved.append((name, spec))
             else:
                 kwargs[name] = value
         elif field.null and not required_before_save:
@@ -431,6 +434,7 @@ def import_archive(parsed: ParsedArchive, *, conflict_strategy: str, dry_run: bo
                 if value is MISSING_REFERENCE:
                     continue
                 obj = resolved[record_id]
+                compatibility.release_unique_relation(obj, name, value)
                 setattr(obj, name, value)
                 compatibility.save(obj, update_fields=[name])
 

netbox_export/services/plugin_compat.py

@@ -52,6 +52,10 @@ def relation_required_before_save(field) -> bool:
     )
 
 
+def relation_should_be_deferred(field) -> bool:
+    return bool(field.null and field.unique and not relation_required_before_save(field))
+
+
 class PluginCompatibility:
     def __init__(
         self,
@@ -131,3 +135,22 @@ class PluginCompatibility:
             if not self._is_missing_tenant_error(exc) or not self._assign_fallback_tenant(obj, force=True):
                 raise
             return obj.save(**kwargs)
+
+    def release_unique_relation(self, obj, field_name: str, value):
+        field = obj._meta.get_field(field_name)
+        if value is None or not relation_should_be_deferred(field):
+            return
+
+        conflicts = type(obj)._default_manager.filter(**{field.attname: value.pk})
+        if obj.pk is not None:
+            conflicts = conflicts.exclude(pk=obj.pk)
+        conflict_ids = list(conflicts.values_list("pk", flat=True))
+        if not conflict_ids:
+            return
+
+        type(obj)._default_manager.filter(pk__in=conflict_ids).update(**{field.attname: None})
+        identifiers = ", ".join(str(pk) for pk in conflict_ids)
+        self.warnings.append(
+            f"Eindeutige Referenz {obj._meta.label_lower}.{field_name} wurde von Zielobjekt(en) "
+            f"{identifiers} gelöst und dem importierten Objekt neu zugeordnet."
+        )