fix: wrap IntegrityError catches in transaction.atomic savepoints

Author: herzog0

mailing_list/views.py

@@ -7,7 +7,7 @@
 from django.contrib.auth.mixins import LoginRequiredMixin
 from django.core import signing
 from django.core.cache import cache
-from django.db import IntegrityError
+from django.db import IntegrityError, transaction
 from django.core.mail import send_mail
 from django.http import HttpResponseRedirect
 from django.shortcuts import render
@@ -149,11 +149,12 @@ def post(self, request):
 
         for list_id in to_subscribe:
             try:
-                UserMailingListSubscription.objects.update_or_create(
-                    user=request.user,
-                    list_id=list_id,
-                    defaults={"email": email, "status": SubscriptionStatus.PENDING},
-                )
+                with transaction.atomic():
+                    UserMailingListSubscription.objects.update_or_create(
+                        user=request.user,
+                        list_id=list_id,
+                        defaults={"email": email, "status": SubscriptionStatus.PENDING},
+                    )
             except IntegrityError:
                 errors.append(list_id)
                 continue
@@ -315,12 +316,13 @@ def _handle_authenticated(self, request, email, list_id, managed_lists):
             return _prg_redirect(request)
 
         try:
-            UserMailingListSubscription.objects.create(
-                user=request.user,
-                list_id=list_id,
-                email=email,
-                status=SubscriptionStatus.PENDING,
-            )
+            with transaction.atomic():
+                UserMailingListSubscription.objects.create(
+                    user=request.user,
+                    list_id=list_id,
+                    email=email,
+                    status=SubscriptionStatus.PENDING,
+                )
         except IntegrityError:
             if _is_htmx(request):
                 return self._card(