magic-removal: Refs 1219 -- Added DELETE_ALL=True safety mechanism to prevent accidental deletion of entire table contents.

git-svn-id: http://code.djangoproject.com/svn/django/branches/magic-removal@2047 bcc190cf-cafb-0310-a4f2-bffc1f526a37

django/db/models/manager.py

@@ -100,7 +100,7 @@ class Manager(object):
 
         # Check if extra tables are allowed. If not, throw an error
         if (tables or joins) and not allow_joins:
-            raise TypeError("Joins are not allowed in this type of query")
+            raise TypeError, "Joins are not allowed in this type of query"
 
         # Compose the join dictionary into SQL describing the joins.
         if joins:
@@ -150,6 +150,11 @@ class Manager(object):
         return select, " ".join(sql), params
 
     def delete(self, *args, **kwargs):
+        nArguments = len(args) + len(kwargs)
+
+        # remove the DELETE_ALL argument, if it exists 
+        delete_all = kwargs.pop('DELETE_ALL', False)
+
         # disable non-supported fields
         kwargs['select_related'] = False
         kwargs['select'] = {}
@@ -157,6 +162,10 @@ class Manager(object):
         kwargs['offset'] = None
         kwargs['limit'] = None
 
+        # Check that there at least one query argument
+        if nArguments == 0 and not delete_all:
+            raise TypeError, "SAFTEY MECHANISM: Specify DELETE_ALL=True if you actually want to delete all data"
+                        
         opts = self.klass._meta
 
         # Perform the SQL delete

tests/modeltests/basic/models.py

@@ -210,6 +210,15 @@ AttributeError: Manager isn't accessible via Article instances
 >>> Article.objects.get_count()
 4L
 
+>>> Article.objects.delete()
+Traceback (most recent call last):
+    ...
+TypeError: SAFTEY MECHANISM: Specify DELETE_ALL=True if you actually want to delete all data
+
+>>> Article.objects.delete(DELETE_ALL=True)
+>>> Article.objects.get_count()
+0L
+
 """
 
 from django.conf import settings