Fixed #27626 -- Moved MEDIA_URL/STATIC_URL validation to a system check.

2 files changed, 19 insertions, 12 deletions

diff --git a/django/conf/__init__.py b/django/conf/__init__.py
index e9611aa3fe..4fec2ee646 100644
--- a/django/conf/__init__.py
+++ b/django/conf/__init__.py
@@ -74,17 +74,7 @@ class LazySettings(LazyObject):
         return self._wrapped is not empty
 
 
-class BaseSettings(object):
-    """
-    Common logic for settings whether set by a module or by the user.
-    """
-    def __setattr__(self, name, value):
-        if name in ("MEDIA_URL", "STATIC_URL") and value and not value.endswith('/'):
-            raise ImproperlyConfigured("If set, %s must end with a slash" % name)
-        object.__setattr__(self, name, value)
-
-
-class Settings(BaseSettings):
+class Settings(object):
     def __init__(self, settings_module):
         # update this dict from global settings (but only for ALL_CAPS settings)
         for setting in dir(global_settings):
@@ -137,7 +127,7 @@ class Settings(BaseSettings):
         }
 
 
-class UserSettingsHolder(BaseSettings):
+class UserSettingsHolder(object):
     """
     Holder for user configured settings.
     """
diff --git a/django/core/checks/urls.py b/django/core/checks/urls.py
index 8187a4e561..e950cb5637 100644
--- a/django/core/checks/urls.py
+++ b/django/core/checks/urls.py
@@ -90,3 +90,20 @@ def get_warning_for_invalid_pattern(pattern):
         hint=hint,
         id="urls.E004",
     )]
+
+
+@register(Tags.urls)
+def check_url_settings(app_configs, **kwargs):
+    errors = []
+    for name in ('STATIC_URL', 'MEDIA_URL'):
+        value = getattr(settings, name)
+        if value and not value.endswith('/'):
+            errors.append(E006(name))
+    return errors
+
+
+def E006(name):
+    return Error(
+        'The {} setting must end with a slash.'.format(name),
+        id='urls.E006',
+    )