Fixed reason field being shared between models.

AUTHORS.rst

@@ -111,6 +111,7 @@ Authors
 - Nathan Villagaray-Carski (`ncvc <https://github.com/ncvc>`_)
 - Nianpeng Li
 - Nick Träger
+- Noam Kushinsky (`noamkush <https://github.com/noamkush>`_)
 - Noel James (`NoelJames <https://github.com/NoelJames>`_)
 - Ofek Lev (`ofek <https://github.com/ofek>`_)
 - Phillip Marshall

CHANGES.rst

@@ -4,6 +4,8 @@ Changes
 Unreleased
 ----------
 
+- Fixed history_change_reason_field being shared across inherited models (gh-1433)
+
 3.8.0 (2025-01-23)
 ------------------
 

simple_history/models.py

@@ -410,8 +410,9 @@ def copy_fields(self, model):
 
     def _get_history_change_reason_field(self):
         if self.history_change_reason_field:
-            # User specific field from init
-            history_change_reason_field = self.history_change_reason_field
+            # User specific field from init.
+            # It's cloned so a reason from an inherited model isn't shared.
+            history_change_reason_field = self.history_change_reason_field.clone()
         elif getattr(
             settings, "SIMPLE_HISTORY_HISTORY_CHANGE_REASON_USE_TEXT_FIELD", False
         ):

simple_history/tests/models.py

@@ -650,6 +650,12 @@ class Meta:
         abstract = True
 
 
+class TrackedAbstractBaseWithReasonField(models.Model):
+    history = HistoricalRecords(
+        inherit=True, history_change_reason_field=models.TextField()
+    )
+
+
 class UntrackedAbstractBase(models.Model):
     class Meta:
         abstract = True
@@ -709,6 +715,14 @@ class InheritTracking4(TrackedAbstractBaseA):
     pass
 
 
+class InheritReasonField1(TrackedAbstractBaseWithReasonField):
+    pass
+
+
+class InheritReasonField2(TrackedAbstractBaseWithReasonField):
+    pass
+
+
 class BasePlace(models.Model):
     name = models.CharField(max_length=50)
     history = HistoricalRecords(inherit=True, table_name="base_places_history")

simple_history/tests/tests/test_models.py

@@ -71,6 +71,8 @@
     HistoricalPollWithManyToMany_places,
     HistoricalState,
     InheritedRestaurant,
+    InheritReasonField1,
+    InheritReasonField2,
     Library,
     ManyToManyModelOther,
     ModelWithCustomAttrOneToOneField,
@@ -686,6 +688,29 @@ def test_user_textfield_history_change_reason(self):
         self.assertTrue(isinstance(field, models.TextField))
         self.assertEqual(history.history_change_reason, reason)
 
+    def test_inherited_history_change_reason_update(self):
+        inherited1 = InheritReasonField1.history.create(
+            history_change_reason="reason1", id=1, history_date=datetime.now()
+        )
+        inherited2 = InheritReasonField2.history.create(
+            history_change_reason="reason2", id=1, history_date=datetime.now()
+        )
+
+        InheritReasonField1.history.update(history_change_reason="new_reason1")
+        InheritReasonField2.history.update(history_change_reason="new_reason2")
+
+        inherited1.refresh_from_db()
+        inherited2.refresh_from_db()
+
+        self.assertEqual(inherited1.history_change_reason, "new_reason1")
+        self.assertEqual(inherited2.history_change_reason, "new_reason2")
+
+    def test_history_change_reason_field_not_shared(self):
+        self.assertIsNot(
+            InheritReasonField1.history.model._meta.get_field("history_change_reason"),
+            InheritReasonField2.history.model._meta.get_field("history_change_reason"),
+        )
+
     def test_history_diff_includes_changed_fields(self):
         p = Poll.objects.create(question="what's up?", pub_date=today)
         p.question = "what's up, man?"