Add migration and explanation

website/members/forms.py

@@ -6,6 +6,7 @@
 from django.core.validators import RegexValidator
 from django.utils.translation import gettext_lazy as _
 
+from members.models import Member
 from thabloid.models.thabloid_user import ThabloidUser
 
 from .models import Profile
@@ -55,13 +56,16 @@ def __init__(self, *args, **kwargs):
             ].hidden_widget()
 
         if (
-            not kwargs["instance"].user.has_been_member()
+            not Member.objects.get(pk=kwargs["instance"].user_id).has_been_member()
             and not kwargs["instance"].receive_oldmembers
         ):
             self.fields["receive_oldmembers"].disabled = True
-            # TODO: Explain why.
-
-            # TODO: migration to set False for benefactors created after 2016-2017.
+            self.fields["receive_oldmembers"].help_text = (
+                "If you are a past member, receive emails about Thalia events aimed at alumni. "
+                "You cannot enable this option, as we don't have any records of you having been a member "
+                "(a long time ago, we didn't keep track of this yet). Contact "
+                "<a href='mailto:[email protected]'>[email protected]</a> if you want to receive alumni emails."
+            )
 
         self.render_app_specific_profile_form_fields()
 

website/members/migrations/0048_auto_20231121_2025.py

@@ -0,0 +1,50 @@
+# Generated by Django 4.2.7 on 2023-11-21 19:25
+
+from django.db import migrations
+from django.db.models import Exists, OuterRef
+
+
+def deregister_recent_benefactors_from_oldmembers_mailinglist(apps, schema_editor):
+    """Deregister all benefactors since 2017 from the oldmembers mailinglist.
+
+    We've changed the oldmembers list to include everyone with the 'receive_oldmembers'
+    preference set, regardless of whether they have been a member in the past. Newly made
+    benefactors are automatically excluded, and any existing members or benefactors are
+    included. This is because for many people, we don't have a complete history of their
+    memberships.
+
+    To prevent recently created benefactors (of which we do have a complete history) from
+    being included in the oldmembers list, we need to set their 'receive_oldmembers' False.
+    """
+    Profile = apps.get_model("members", "Profile")
+    Member = apps.get_model("members", "Member")
+    Membership = apps.get_model("members", "Membership")
+
+    # Get people made after the initial migration (+- 2016-12-06) who have only been a benefactor.
+    benefactors = (
+        Member.objects.filter(date_joined__gte="2017-01-01")
+        .filter(
+            Exists(Membership.objects.filter(user=OuterRef("pk"), type="benefactor"))
+        )
+        .exclude(
+            Exists(
+                Membership.objects.filter(user=OuterRef("pk"), type="member"),
+            )
+        )
+    )
+
+    # Set 'receive_oldmembers' to False for all benefactors since 2017
+    Profile.objects.filter(user__in=benefactors).update(receive_oldmembers=False)
+
+
+class Migration(migrations.Migration):
+    dependencies = [
+        ("members", "0048_alter_profile_photo"),
+    ]
+
+    operations = [
+        migrations.RunPython(
+            deregister_recent_benefactors_from_oldmembers_mailinglist,
+            migrations.RunPython.noop,
+        )
+    ]