fix: use sender for m2m signal dispatch connection

CHANGELOG.md

@@ -12,6 +12,7 @@
 
 #### Fixes
 
+- fix: Use sender instead of receiver for `m2m_changed` signal ID to prevent duplicate entries for models that share a related model. ([#686](https://github.com/jazzband/django-auditlog/pull/686))
 - Fixed a problem when setting `Value(None)` in `JSONField` ([#646](https://github.com/jazzband/django-auditlog/pull/646))
 - Fixed a problem when setting `django.db.models.functions.Now()` in `DateTimeField` ([#635](https://github.com/jazzband/django-auditlog/pull/635))
 

auditlog/registry.py

@@ -202,7 +202,7 @@ def _connect_signals(self, model):
                 m2m_changed.connect(
                     receiver,
                     sender=m2m_model,
-                    dispatch_uid=self._dispatch_uid(m2m_changed, receiver),
+                    dispatch_uid=self._m2m_dispatch_uid(m2m_changed, m2m_model),
                 )
 
     def _disconnect_signals(self, model):
@@ -218,14 +218,18 @@ def _disconnect_signals(self, model):
             m2m_model = getattr(field, "through")
             m2m_changed.disconnect(
                 sender=m2m_model,
-                dispatch_uid=self._dispatch_uid(m2m_changed, receiver),
+                dispatch_uid=self._m2m_dispatch_uid(m2m_changed, m2m_model),
             )
         del self._m2m_signals[model]
 
     def _dispatch_uid(self, signal, receiver) -> DispatchUID:
         """Generate a dispatch_uid which is unique for a combination of self, signal, and receiver."""
         return id(self), id(signal), id(receiver)
 
+    def _m2m_dispatch_uid(self, signal, sender) -> DispatchUID:
+        """Generate a dispatch_uid which is unique for a combination of self, signal, and sender."""
+        return id(self), id(signal), id(sender)
+
     def _get_model_classes(self, app_model: str) -> list[ModelBase]:
         try:
             try:

auditlog_tests/models.py

@@ -133,6 +133,61 @@ class ManyRelatedOtherModel(models.Model):
     history = AuditlogHistoryField(delete_related=True)
 
 
+class ReusableThroughRelatedModel(models.Model):
+    """
+    A model related to multiple other models through a model.
+    """
+
+    label = models.CharField(max_length=100)
+
+
+class ReusableThroughModel(models.Model):
+    """
+    A through model that can be associated multiple different models.
+    """
+
+    label = models.ForeignKey(
+        ReusableThroughRelatedModel,
+        on_delete=models.CASCADE,
+        related_name="%(app_label)s_%(class)s_items",
+    )
+    one = models.ForeignKey(
+        "ModelForReusableThroughModel", on_delete=models.CASCADE, null=True, blank=True
+    )
+    two = models.ForeignKey(
+        "OtherModelForReusableThroughModel",
+        on_delete=models.CASCADE,
+        null=True,
+        blank=True,
+    )
+
+
+class ModelForReusableThroughModel(models.Model):
+    """
+    A model with many-to-many relations through a shared model.
+    """
+
+    name = models.CharField(max_length=200)
+    related = models.ManyToManyField(
+        ReusableThroughRelatedModel, through=ReusableThroughModel
+    )
+
+    history = AuditlogHistoryField(delete_related=True)
+
+
+class OtherModelForReusableThroughModel(models.Model):
+    """
+    Another model with many-to-many relations through a shared model.
+    """
+
+    name = models.CharField(max_length=200)
+    related = models.ManyToManyField(
+        ReusableThroughRelatedModel, through=ReusableThroughModel
+    )
+
+    history = AuditlogHistoryField(delete_related=True)
+
+
 @auditlog.register(include_fields=["label"])
 class SimpleIncludeModel(models.Model):
     """
@@ -364,6 +419,8 @@ class AutoManyRelatedModel(models.Model):
 auditlog.register(ManyRelatedModel)
 auditlog.register(ManyRelatedModel.recursive.through)
 m2m_only_auditlog.register(ManyRelatedModel, m2m_fields={"related"})
+m2m_only_auditlog.register(ModelForReusableThroughModel, m2m_fields={"related"})
+m2m_only_auditlog.register(OtherModelForReusableThroughModel, m2m_fields={"related"})
 auditlog.register(SimpleExcludeModel, exclude_fields=["text"])
 auditlog.register(SimpleMappingModel, mapping_fields={"sku": "Product No."})
 auditlog.register(AdditionalDataIncludedModel)

auditlog_tests/tests.py

@@ -46,12 +46,14 @@
     JSONModel,
     ManyRelatedModel,
     ManyRelatedOtherModel,
+    ModelForReusableThroughModel,
     ModelPrimaryKeyModel,
     NoDeleteHistoryModel,
     NullableJSONModel,
     PostgresArrayFieldModel,
     ProxyModel,
     RelatedModel,
+    ReusableThroughRelatedModel,
     SerializeNaturalKeyRelatedModel,
     SerializeOnlySomeOfThisModel,
     SerializePrimaryKeyRelatedModel,
@@ -390,6 +392,8 @@ def setUp(self):
         self.obj = ManyRelatedModel.objects.create()
         self.recursive = ManyRelatedModel.objects.create()
         self.related = ManyRelatedOtherModel.objects.create()
+        self.obj_reusable = ModelForReusableThroughModel.objects.create()
+        self.obj_reusable_related = ReusableThroughRelatedModel.objects.create()
         self.base_log_entry_count = (
             LogEntry.objects.count()
         )  # created by the create() calls above
@@ -485,6 +489,11 @@ def test_object_repr_related_deleted(self):
             log_entry = self.obj.history.first()
             self.assertEqual(log_entry.object_repr, DEFAULT_OBJECT_REPR)
 
+    def test_changes_not_duplicated_with_reusable_through_model(self):
+        self.obj_reusable.related.add(self.obj_reusable_related)
+        entries = self.obj_reusable.history.all()
+        self.assertEqual(len(entries), 1)
+
 
 class MiddlewareTest(TestCase):
     """
@@ -1255,7 +1264,7 @@ def test_register_models_register_app(self):
 
         self.assertTrue(self.test_auditlog.contains(SimpleExcludeModel))
         self.assertTrue(self.test_auditlog.contains(ChoicesFieldModel))
-        self.assertEqual(len(self.test_auditlog.get_models()), 27)
+        self.assertEqual(len(self.test_auditlog.get_models()), 31)
 
     def test_register_models_register_model_with_attrs(self):
         self.test_auditlog._register_models(