fix: reconcile component mappings by natural key

README.md

@@ -122,6 +122,9 @@ anderem die Plattformzuordnung von NetBox-SLM-Softwareinstallationen.
 Eindeutige optionale Beziehungen wie die primären IP-Adressen von Geräten und
 virtuellen Maschinen werden in einer zweiten Phase zugewiesen. Eine veraltete
 Zielzuordnung wird dabei atomar gelöst und als Warnung protokolliert.
+Gespeicherte Importzuordnungen werden bei Wiederholungsimporten gegen den
+aktuellen Fachschlüssel geprüft. Existiert das Objekt bereits unter diesem
+Schlüssel, wird die Zuordnung korrigiert, statt ein Duplikat anzulegen.
 
 Auf Quelle und Ziel müssen jeweils dieselben Plugin-Versionen und Migrationen
 installiert sein. Verschlüsselte Zugangsdaten von NetBox-VM-Import sind nur bei

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 = "0.3.6"
+    version = "0.3.7"
     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": "0.3.6",
+        "plugin_version": "0.3.7",
         "scope": {
             "type": scope_type,
             "source_pk": str(scope_id),

netbox_export/services/importer.py

@@ -38,6 +38,8 @@ EXPLICIT_IDENTITIES = {
     "dcim.consoleserverport": ("device", "name"),
     "dcim.powerport": ("device", "name"),
     "dcim.poweroutlet": ("device", "name"),
+    "dcim.frontport": ("device", "name"),
+    "dcim.rearport": ("device", "name"),
     "dcim.devicebay": ("device", "name"),
     "dcim.modulebay": ("device", "name"),
     "dcim.inventoryitem": ("device", "parent", "name"),
@@ -191,19 +193,24 @@ def _mapped_object(source_instance: uuid.UUID, record: dict, model):
 
 def _find_existing(source_instance, model, record, resolver):
     mapped = _mapped_object(source_instance, record, model)
-    if mapped is not None:
-        return mapped
     lookup = _identity_lookup(model, record, resolver)
     if not lookup:
-        return None
+        return mapped
     try:
-        return model._default_manager.get(**lookup)
+        natural = model._default_manager.get(**lookup)
     except model.DoesNotExist:
-        return None
+        return mapped
     except model.MultipleObjectsReturned as exc:
         raise ImportConflictError(
             f"Mehrere Zielobjekte passen auf {record['model']} mit {lookup}."
         ) from exc
+    if mapped is not None and mapped.pk != natural.pk:
+        resolver.warn(
+            ("mapping-rebound", record["id"]),
+            f"Gespeicherte Zuordnung für {record['id']} wurde von Ziel-ID {mapped.pk} auf "
+            f"Ziel-ID {natural.pk} korrigiert, da der Fachschlüssel {lookup} bereits existiert.",
+        )
+    return natural
 
 
 def _write_mapping(source_instance, record, obj):

pyproject.toml

@@ -4,7 +4,7 @@ build-backend = "setuptools.build_meta"
 
 [project]
 name = "netbox-export"
-version = "0.3.6"
+version = "0.3.7"
 description = "Portable ZIP export and import for scoped NetBox data"
 readme = "README.md"
 requires-python = ">=3.12"

tests/test_importer_plugin_compat.py

@@ -1,9 +1,11 @@
+import uuid
 from typing import ClassVar
 
 import pytest
 from django.db import connection, models
 
-from netbox_export.services.importer import _field_kwargs
+from netbox_export.services import importer as importer_module
+from netbox_export.services.importer import _field_kwargs, _find_existing
 from netbox_export.services.plugin_compat import PluginCompatibility
 from netbox_export.services.references import ReferenceResolver
 
@@ -52,6 +54,25 @@ class UniqueAddressOwner(models.Model):
         app_label = "compat_tests"
 
 
+class Device(models.Model):
+    class Meta:
+        app_label = "dcim"
+
+
+class RearPort(models.Model):
+    device = models.ForeignKey(Device, on_delete=models.CASCADE)
+    name = models.CharField(max_length=64)
+
+    class Meta:
+        app_label = "dcim"
+        constraints: ClassVar[list] = [
+            models.UniqueConstraint(
+                fields=("device", "name"),
+                name="dcim_rearport_unique_device_name",
+            )
+        ]
+
+
 def tenant_record():
     return {
         "fields": {},
@@ -164,3 +185,46 @@ def test_existing_unique_relation_is_released_before_reassignment():
         with connection.schema_editor() as schema_editor:
             schema_editor.delete_model(UniqueAddressOwner)
             schema_editor.delete_model(UniqueAddress)
+
+
+def test_natural_key_rebinds_stale_mapping_instead_of_creating_duplicate(monkeypatch):
+    with connection.schema_editor() as schema_editor:
+        schema_editor.create_model(Device)
+        schema_editor.create_model(RearPort)
+    try:
+        device = Device.objects.create()
+        natural = RearPort.objects.create(device=device, name="3-LC")
+        stale_mapping_target = RearPort(pk=999, device=device, name="Alt")
+        monkeypatch.setattr(
+            importer_module,
+            "_mapped_object",
+            lambda source_instance, record, model: stale_mapping_target,
+        )
+        warnings = []
+        resolver = ReferenceResolver(
+            {"dcim.device:160": device},
+            warnings,
+            lambda label: None,
+        )
+        record = {
+            "id": "dcim.rearport:77",
+            "model": "dcim.rearport",
+            "source_pk": "77",
+            "fields": {"name": "3-LC"},
+            "relations": {"device": {"ref": "dcim.device:160"}},
+        }
+
+        existing = _find_existing(uuid.uuid4(), RearPort, record, resolver)
+
+        assert existing == natural
+        assert warnings == [
+            (
+                "Gespeicherte Zuordnung für dcim.rearport:77 wurde von Ziel-ID 999 auf "
+                f"Ziel-ID {natural.pk} korrigiert, da der Fachschlüssel "
+                f"{{'device': <Device: Device object ({device.pk})>, 'name': '3-LC'}} bereits existiert."
+            )
+        ]
+    finally:
+        with connection.schema_editor() as schema_editor:
+            schema_editor.delete_model(RearPort)
+            schema_editor.delete_model(Device)