Normalize newlines from form

constance/admin.py

@@ -19,6 +19,7 @@
 from django.utils.encoding import smart_bytes
 from django.utils.formats import localize
 from django.utils.module_loading import import_string
+from django.utils.text import normalize_newlines
 from django.utils.translation import ugettext_lazy as _
 
 from . import LazyConfig, settings
@@ -146,6 +147,9 @@ def save(self):
             current = getattr(config, name)
             new = self.cleaned_data[name]
 
+            if isinstance(new, str):
+                new = normalize_newlines(new)
+
             if conf.settings.USE_TZ and isinstance(current, datetime) and not timezone.is_aware(current):
                 current = timezone.make_aware(current)
 

example/cheeseshop/settings.py

@@ -111,6 +111,7 @@
     'MUSICIANS': (4, 'number of musicians inside the shop'),
     'DATE_ESTABLISHED': (date(1972, 11, 30), "the shop's first opening"),
     'MY_SELECT_KEY': ('yes', 'select yes or no', 'yes_no_null_select'),
+    'MULTILINE': ('Line one\nLine two', 'multiline string'),
 }
 
 CONSTANCE_BACKEND = 'constance.backends.database.DatabaseBackend'

tests/test_admin.py

@@ -11,6 +11,7 @@
 
 from constance import settings
 from constance.admin import Config
+from constance.admin import get_values
 
 
 class TestAdmin(TestCase):
@@ -117,6 +118,26 @@ def test_submit(self):
                 response = self.options.changelist_view(request, {})
         self.assertIsInstance(response, HttpResponseRedirect)
 
+    @mock.patch('constance.settings.CONFIG_FIELDSETS', {
+        'FieldSetOne': ('MULTILINE',)
+    })
+    @mock.patch('constance.settings.CONFIG', {
+        'MULTILINE': ('Hello\nWorld', 'multiline value'),
+    })
+    @mock.patch('constance.settings.IGNORE_ADMIN_VERSION_CHECK', True)
+    def test_newlines_normalization(self):
+        self.client.login(username='admin', password='nimda')
+        request = self.rf.post('/admin/constance/config/', data={
+            "MULTILINE": "Hello\r\nWorld",
+            "version": "123",
+        })
+        request.user = self.superuser
+        request._dont_enforce_csrf_checks = True
+        with mock.patch("django.contrib.messages.add_message"):
+            response = self.options.changelist_view(request, {})
+        self.assertIsInstance(response, HttpResponseRedirect)
+        self.assertEqual(get_values()['MULTILINE'], 'Hello\nWorld')
+
     @mock.patch('constance.settings.CONFIG', {
         'DATETIME_VALUE': (datetime(2019, 8, 7, 18, 40, 0), 'some naive datetime'),
     })