Use pre_delete signal insted of Model.delete() to prevent note balance issues when deleting a transaction (don't do it) in Django Admin

apps/note/apps.py

@@ -3,7 +3,7 @@
 
 from django.apps import AppConfig
 from django.conf import settings
-from django.db.models.signals import post_save
+from django.db.models.signals import post_save, pre_delete
 from django.utils.translation import gettext_lazy as _
 
 from . import signals
@@ -25,3 +25,8 @@ class NoteConfig(AppConfig):
             signals.save_club_note,
             sender='member.Club',
         )
+
+        pre_delete.connect(
+            signals.delete_transaction,
+            sender='note.transaction',
+        )

apps/note/models/transactions.py

@@ -242,14 +242,6 @@ class Transaction(PolymorphicModel):
         self.destination._force_save = True
         self.destination.save()
 
-    def delete(self, **kwargs):
-        """
-        Whenever we want to delete a transaction (caution with this), we ensure the transaction is invalid first.
-        """
-        self.valid = False
-        self.save(**kwargs)
-        super().delete(**kwargs)
-
     @property
     def total(self):
         return self.amount * self.quantity

apps/note/signals.py

@@ -24,3 +24,11 @@ def save_club_note(instance, raw, **_kwargs):
     from .models import NoteClub
     NoteClub.objects.get_or_create(club=instance)
     instance.note.save()
+
+
+def delete_transaction(instance, **_kwargs):
+    """
+    Whenever we want to delete a transaction (caution with this), we ensure the transaction is invalid first.
+    """
+    instance.valid = False
+    instance.save()