fix: prevent module component duplication during import

tests/test_importer_plugin_compat.py

@@ -5,7 +5,11 @@ import pytest
 from django.db import connection, models
 
 from netbox_export.services import importer as importer_module
-from netbox_export.services.importer import _field_kwargs, _find_existing
+from netbox_export.services.importer import (
+    _field_kwargs,
+    _find_existing,
+    _identity_lookup,
+)
 from netbox_export.services.plugin_compat import PluginCompatibility
 from netbox_export.services.references import ReferenceResolver
 
@@ -73,6 +77,27 @@ class RearPort(models.Model):
         ]
 
 
+class Module(models.Model):
+    class Meta:
+        app_label = "dcim"
+
+
+class ModuleBay(models.Model):
+    device = models.ForeignKey(Device, on_delete=models.CASCADE)
+    module = models.ForeignKey(Module, on_delete=models.CASCADE)
+    name = models.CharField(max_length=64)
+
+    class Meta:
+        app_label = "dcim"
+
+
+class ModularRearPort(models.Model):
+    module = models.ForeignKey(Module, on_delete=models.SET_NULL, null=True)
+
+    class Meta:
+        app_label = "compat_tests"
+
+
 def tenant_record():
     return {
         "fields": {},
@@ -132,6 +157,50 @@ def test_unresolved_relation_in_check_constraint_blocks_initial_save():
     assert missing_required == []
 
 
+def test_modular_component_waits_for_module_before_initial_save():
+    resolver = ReferenceResolver({}, [], lambda label: None)
+    record = {
+        "fields": {},
+        "relations": {"module": {"ref": "dcim.module:12"}},
+    }
+
+    kwargs, unresolved, unresolved_values, missing_required = _field_kwargs(
+        ModularRearPort,
+        record,
+        resolver,
+        tenant_required=False,
+    )
+
+    assert kwargs is None
+    assert unresolved == []
+    assert unresolved_values == []
+    assert missing_required == []
+
+
+def test_module_bay_identity_includes_owning_module():
+    device = Device(pk=210)
+    module = Module(pk=12)
+    resolver = ReferenceResolver(
+        {
+            "dcim.device:210": device,
+            "dcim.module:12": module,
+        },
+        [],
+        lambda label: None,
+    )
+    record = {
+        "fields": {"name": "3-LC"},
+        "relations": {
+            "device": {"ref": "dcim.device:210"},
+            "module": {"ref": "dcim.module:12"},
+        },
+    }
+
+    lookup = _identity_lookup(ModuleBay, record, resolver)
+
+    assert lookup == {"device": device, "module": module, "name": "3-LC"}
+
+
 def test_resolved_nullable_unique_relation_is_deferred():
     address = UniqueAddress(pk=50)
     resolver = ReferenceResolver(

tests/test_plugin_compat.py

@@ -7,6 +7,7 @@ from netbox_export.services.plugin_compat import (
     MISSING_TENANT_MESSAGE,
     PluginCompatibility,
     check_constraint_field_names,
+    is_module_relation,
     is_tenant_relation,
     relation_required_before_save,
     relation_should_be_deferred,
@@ -86,6 +87,27 @@ def test_identifies_tenant_relation():
     assert is_tenant_relation(relation_field("site", "dcim.site")) is False
 
 
+def test_identifies_module_component_relation():
+    assert is_module_relation(relation_field("module", "dcim.module")) is True
+    assert is_module_relation(relation_field("device", "dcim.device")) is False
+
+
+def test_new_module_disables_automatic_component_replication():
+    module = SimpleNamespace(_meta=SimpleNamespace(label_lower="dcim.module"))
+
+    PluginCompatibility.prepare_initial_save(module, is_new=True)
+
+    assert module._disable_replication is True
+
+
+def test_existing_module_keeps_normal_save_behavior():
+    module = SimpleNamespace(_meta=SimpleNamespace(label_lower="dcim.module"))
+
+    PluginCompatibility.prepare_initial_save(module, is_new=False)
+
+    assert not hasattr(module, "_disable_replication")
+
+
 def test_identifies_relations_used_by_check_constraint():
     constraint = models.CheckConstraint(
         condition=(