Merge branch 'fix-admin-user-search' into 'master'

Fix search in user admin

Closes #964

See merge request !1637

arkindex/users/admin.py

@@ -4,6 +4,7 @@ from django.contrib.auth.admin import UserAdmin as BaseUserAdmin
 from django.contrib.auth.forms import ReadOnlyPasswordHashField
 from django.contrib.auth.models import Group as BaseGroup
 from django.contrib.contenttypes.admin import GenericTabularInline
+from django.db.models.functions import Collate
 from enumfields.admin import EnumFieldListFilter
 
 from arkindex.users.models import Group, OAuthCredentials, Right, User, UserScope
@@ -76,10 +77,18 @@ class UserAdmin(BaseUserAdmin):
             'fields': ('email', 'password1', 'password2')}
          ),
     )
-    search_fields = ('email',)
+    search_fields = ('searchable_email',)
     ordering = ('-created', 'email',)
     filter_horizontal = ()
 
+    def get_queryset(self, request):
+        qs = super().get_queryset(request)
+        # Django's search uses ILIKE, but LIKE is not supported in PostgreSQL with nondeterministic collations.
+        # We are using a case-insensitive collation to get unique case-insensitive emails, so to search properly,
+        # we first have to set the collation back to its default value, making it case-sensitive again;
+        # since Django uses ILIKE, it will be case-insensitive anyway.
+        return qs.annotate(searchable_email=Collate('email', 'default'))
+
 
 class UserScopeAdmin(admin.ModelAdmin):
     list_display = ('user', 'scope')