Allow duplicate email addresses

Unique constraint should be dropped from account_emailaddress table manually because it's already previously added in the account migrations. Instead add unique together constraint for email and user_id fields. See 0002_email_max_length.py migration in allauth/account.

ALTER TABLE account_emailaddress DROP CONSTRAINT account_emailaddress_email_key;
ALTER TABLE account_emailaddress ADD CONSTRAINT account_emailaddress_email_key UNIQUE (user_id, email);

respa/settings.py

@@ -284,6 +284,7 @@ def get_git_revision_hash():
 
 SOCIALACCOUNT_PROVIDERS = {"tampere": {"VERIFIED_EMAIL": True}}
 LOGIN_REDIRECT_URL = "/"
+ACCOUNT_UNIQUE_EMAIL = False
 ACCOUNT_LOGOUT_ON_GET = True
 SOCIALACCOUNT_ADAPTER = "tamusers.adapter.SocialAccountAdapter"
 

users/api.py

@@ -1,4 +1,5 @@
 from allauth.socialaccount.models import EmailAddress
+from django.conf import settings
 from django.contrib.auth import get_user_model
 from rest_framework import permissions, serializers, generics, viewsets, status
 from rest_framework.decorators import action
@@ -97,7 +98,7 @@ def set_email(self, request, pk=None):
                 status=status.HTTP_400_BAD_REQUEST
             )
 
-        if EmailAddress.objects.filter(email=email):
+        if settings.ACCOUNT_UNIQUE_EMAIL and EmailAddress.objects.filter(email=email):
             return Response(
                 {"detail": "The email address is already in use."},
                 status=status.HTTP_400_BAD_REQUEST

users/tests/test_api.py

@@ -1,4 +1,5 @@
 from allauth.account.models import EmailAddress
+from django.conf import settings
 from django.contrib.auth import get_user_model
 from django.urls import reverse
 from rest_framework import status
@@ -64,6 +65,7 @@ def test_set_email_not_provided(self):
         self.assertEqual(self.user.email, "")
 
     def test_set_email_already_in_use(self):
+        settings.ACCOUNT_UNIQUE_EMAIL = True
         url = reverse("user-set-email", kwargs={"pk": self.user.pk})
         data = {"email": "[email protected]"}  # Email already used by other_user
 
@@ -74,3 +76,16 @@ def test_set_email_already_in_use(self):
             response.data, {"detail": "The email address is already in use."}
         )
         self.assertEqual(self.user.email, "")
+
+    def test_allow_to_set_duplicate_email(self):
+        settings.ACCOUNT_UNIQUE_EMAIL = False
+        url = reverse("user-set-email", kwargs={"pk": self.user.pk})
+        data = {"email": "[email protected]"}  # Email already used by other_user
+
+        response = self.client.post(url, data, format="json")
+
+        self.assertEqual(response.status_code, status.HTTP_200_OK)
+        self.assertEqual(
+            response.data, {"detail": "Email set successfully."}
+        )
+        self.assertEqual(self.user.email, "[email protected]")