m2m_fields throws exception when relation is modified using reverse acessor

[amanz360]

Describe the bug
I'm attempting to use the new m2m_fields released in version 3.2.0 but it doesn't appear to handle the m2m related manager on both models properly.

To Reproduce
Steps to reproduce the behavior:
Toy example based on my actual issue

class Lot(models.Model):
    pass

class Shipment(models.Model):
    lots = models.ManyToManyField("Lot", related_name="shipments")
    history = HistoricalRecords(m2m_fields=[lots])

With this relationship and having generated the appropriate migration after, I ran into an exception when existing code attempted to insert records into the through table via the shipments accessor on the Lot model that django would provide

Traceback (most recent call last):
  File "/builds/xxx/xxx-server/xxx/tests/test_daily_brand_alert.py", line 383, in test_forecasted_out_of_stock_alerts
    self.lots1.shipments.add(self.shipment1)
  File "/venvs/xxx/lib/python3.9/site-packages/django/db/models/fields/related_descriptors.py", line 950, in add
    self._add_items(
  File "/venvs/xxx/lib/python3.9/site-packages/django/db/models/fields/related_descriptors.py", line 1159, in _add_items
    signals.m2m_changed.send(
  File "/venvs/xxx/lib/python3.9/site-packages/django/dispatch/dispatcher.py", line 180, in send
    return [
  File "/venvs/xxx/lib/python3.9/site-packages/django/dispatch/dispatcher.py", line 181, in <listcomp>
    (receiver, receiver(signal=self, sender=sender, **named))
  File "/venvs/xxx/lib/python3.9/site-packages/simple_history/models.py", line 637, in m2m_changed
    self.create_historical_record(instance, "~")
  File "/venvs/xxx/lib/python3.9/site-packages/simple_history/models.py", line 698, in create_historical_record
    self.create_historical_record_m2ms(history_instance, instance)
  File "/venvs/xxx/lib/python3.9/site-packages/simple_history/models.py", line 643, in create_historical_record_m2ms
    through_model = getattr(original_instance, field.name).through
AttributeError: 'Lot' object has no attribute 'lots'

Expected behavior
I'd expect defining the m2m_fields on one model to record changes made via the corresponding model without exception

[amanz360]

Noting an obvious workaround is to only call the ManyToMany related manager in one direction, this is the solution I'm using for now.

[michaeljaszczuk]

Have you created and ran migrations?

[andweb-lawcode]

I am facing a similar issue;

Setup to reproduce:

class TestUser(models.Model):
    pass

class Company(models.Model):
    contacts = models.ManyToManyField(TestUser, related_name="contact_in_companies")
    history = HistoricalRecords(m2m_fields=[contacts])

migrations were created and run.

run:

user = TestUser()
user.save()
company = Company()
company.save()
user.contact_in_companies.add(company)

throws the following error:

AttributeError                            Traceback (most recent call last)
Cell In[12], line 1
----> 1 user.contact_in_companies.add(company)

File xxx/lib/python3.9/site-packages/django/db/models/fields/related_descriptors.py:950, in create_forward_many_to_many_manager.<locals>.ManyRelatedManager.add(self, through_defaults, *objs)
    948 db = router.db_for_write(self.through, instance=self.instance)
    949 with transaction.atomic(using=db, savepoint=False):
--> 950     self._add_items(
    951         self.source_field_name, self.target_field_name, *objs,
    952         through_defaults=through_defaults,
    953     )
    954     # If this is a symmetrical m2m relation to self, add the mirror
    955     # entry in the m2m table.
    956     if self.symmetrical:

File xxx/lib/python3.9/site-packages/django/db/models/fields/related_descriptors.py:1159, in create_forward_many_to_many_manager.<locals>.ManyRelatedManager._add_items(self, source_field_name, target_field_name, through_defaults, *objs)
   1150 self.through._default_manager.using(db).bulk_create([
   1151     self.through(**through_defaults, **{
   1152         '%s_id' % source_field_name: self.related_val[0],
   (...)
   1155     for target_id in missing_target_ids
   1156 ], ignore_conflicts=can_ignore_conflicts)
   1158 if must_send_signals:
-> 1159     signals.m2m_changed.send(
   1160         sender=self.through, action='post_add',
   1161         instance=self.instance, reverse=self.reverse,
   1162         model=self.model, pk_set=missing_target_ids, using=db,
   1163     )

File xxx/lib/python3.9/site-packages/django/dispatch/dispatcher.py:180, in Signal.send(self, sender, **named)
    177 if not self.receivers or self.sender_receivers_cache.get(sender) is NO_RECEIVERS:
    178     return []
--> 180 return [
    181     (receiver, receiver(signal=self, sender=sender, **named))
    182     for receiver in self._live_receivers(sender)
    183 ]

File xxx/lib/python3.9/site-packages/django/dispatch/dispatcher.py:181, in <listcomp>(.0)
    177 if not self.receivers or self.sender_receivers_cache.get(sender) is NO_RECEIVERS:
    178     return []
    180 return [
--> 181     (receiver, receiver(signal=self, sender=sender, **named))
    182     for receiver in self._live_receivers(sender)
    183 ]

File xxx/lib/python3.9/site-packages/simple_history/models.py:663, in HistoricalRecords.m2m_changed(self, instance, action, attr, pk_set, reverse, **_)
    659     return
    661 if action in ("post_add", "post_remove", "post_clear"):
    662     # It should be safe to ~ this since the row must exist to modify m2m on it
--> 663     self.create_historical_record(instance, "~")

File xxx/lib/python3.9/site-packages/simple_history/models.py:710, in HistoricalRecords.create_historical_record(self, instance, history_type, using)
    706 history_user = self.get_history_user(instance)
    707 history_change_reason = self.get_change_reason_for_object(
    708     instance, history_type, using
    709 )
--> 710 manager = getattr(instance, self.manager_name)
    712 attrs = {}
    713 for field in self.fields_included(instance):

AttributeError: 'TestUser' object has no attribute 'history'

as @amanz360 pointed out, modifying the relation through Company.contacts works.

django-simple-history v3.5, django 3.2.19