From 30b3a3771efda042aaf8aeca55f7c38eb4f62639 Mon Sep 17 00:00:00 2001
From: Florent Daigniere <nextgens@freenetproject.org>
Date: Sat, 27 Aug 2022 18:09:52 +0200
Subject: [PATCH] Prevent signups with accounts where an alias exists

---
 core/admin/mailu/ui/views/users.py   | 2 +-
 towncrier/newsfragments/2429.feature | 1 +
 2 files changed, 2 insertions(+), 1 deletion(-)
 create mode 100644 towncrier/newsfragments/2429.feature

diff --git a/core/admin/mailu/ui/views/users.py b/core/admin/mailu/ui/views/users.py
index 8790977b..c4b26036 100644
--- a/core/admin/mailu/ui/views/users.py
+++ b/core/admin/mailu/ui/views/users.py
@@ -167,7 +167,7 @@ def user_signup(domain_name=None):
         form = forms.UserSignupFormCaptcha()
 
     if form.validate_on_submit():
-        if domain.has_email(form.localpart.data):
+        if domain.has_email(form.localpart.data) or models.Alias.resolve(form.localpart.data, domain_name):
             flask.flash('Email is already used', 'error')
         else:
             flask.session.regenerate()
diff --git a/towncrier/newsfragments/2429.feature b/towncrier/newsfragments/2429.feature
new file mode 100644
index 00000000..b4a6270a
--- /dev/null
+++ b/towncrier/newsfragments/2429.feature
@@ -0,0 +1 @@
+Prevent signups with accounts for which an SQL-LIKE alias exists.