Fixed #18658 -- Improved ModelAdmin.message_user API

Thanks to Lowe Thiderman for the patch and tests

django/contrib/admin/options.py

@@ -691,12 +691,30 @@ class ModelAdmin(BaseModelAdmin):
         change_message = ' '.join(change_message)
         return change_message or _('No fields changed.')
 
-    def message_user(self, request, message):
+    def message_user(self, request, message, level=messages.INFO, extra_tags='',
+                     fail_silently=False):
         """
         Send a message to the user. The default implementation
         posts a message using the django.contrib.messages backend.
+
+        Exposes almost the same API as messages.add_message(), but accepts the
+        positional arguments in a different order to maintain backwards
+        compatibility. For convenience, it accepts the `level` argument as
+        a string rather than the ususal level number.
         """
-        messages.info(request, message)
+
+        if not isinstance(level, int):
+            # attempt to get the level if passed a string
+            try:
+                level = getattr(messages.constants, level.upper())
+            except AttributeError:
+                levels = messages.constants.DEFAULT_TAGS.values()
+                levels_repr = ', '.join('`%s`' % l for l in levels)
+                raise ValueError('Bad message level string: `%s`. '
+                        'Possible values are: %s' % (level, levels_repr))
+
+        messages.add_message(request, level, message, extra_tags=extra_tags,
+                fail_silently=fail_silently)
 
     def save_form(self, request, form, change):
         """