Fix history_id_field not working with m2m

Author: legau

simple_history/models.py

@@ -400,7 +400,7 @@ def _get_history_change_reason_field(self):
 
     def _get_history_id_field(self):
         if self.history_id_field:
-            history_id_field = self.history_id_field
+            history_id_field = self.history_id_field.clone()
             history_id_field.primary_key = True
             history_id_field.editable = False
         elif getattr(settings, "SIMPLE_HISTORY_HISTORY_ID_USE_UUID", False):

simple_history/tests/models.py

@@ -117,6 +117,16 @@ class PollWithManyToMany(models.Model):
     history = HistoricalRecords(m2m_fields=[places])
 
 
+class PollWithManyToManyCustomHistoryID(models.Model):
+    question = models.CharField(max_length=200)
+    pub_date = models.DateTimeField("date published")
+    places = models.ManyToManyField("Place")
+
+    history = HistoricalRecords(
+        m2m_fields=[places], history_id_field=models.UUIDField(default=uuid.uuid4)
+    )
+
+
 class HistoricalRecordsWithExtraFieldM2M(HistoricalRecords):
     def get_extra_fields_m2m(self, model, through_model, fields):
         extra_fields = super().get_extra_fields_m2m(model, through_model, fields)

simple_history/tests/tests/test_models.py

@@ -98,6 +98,7 @@
     PollWithExcludeFields,
     PollWithHistoricalIPAddress,
     PollWithManyToMany,
+    PollWithManyToManyCustomHistoryID,
     PollWithManyToManyWithIPAddress,
     PollWithNonEditableField,
     PollWithSeveralManyToMany,
@@ -1848,6 +1849,14 @@ def test_diff(self):
         self.assertEqual(2, len(delta.changes[0].new))
 
 
+class ManyToManyCustomIDTest(TestCase):
+    def setUp(self):
+        self.model = PollWithManyToManyCustomHistoryID
+        self.history_model = self.model.history.model
+        self.place = Place.objects.create(name="Home")
+        self.poll = self.model.objects.create(question="what's up?", pub_date=today)
+
+
 class ManyToManyTest(TestCase):
     def setUp(self):
         self.model = PollWithManyToMany