Fail-fast for invalid read_deleted values

Fixes bug 961588

Change-Id: Ib02d89485cdf4626698b959a2136841109cdc51f

nova/context.py

@@ -55,9 +55,6 @@ def __init__(self, user_id, project_id, is_admin=None, read_deleted="no",
         :param kwargs: Extra arguments that might be present, but we ignore
             because they possibly came in from older rpc messages.
         """
-        if read_deleted not in ('no', 'yes', 'only'):
-            raise ValueError(_("read_deleted can only be one of 'no', "
-                               "'yes' or 'only', not %r") % read_deleted)
         if kwargs:
             LOG.warn(_('Arguments dropped when creating context: %s') %
                     str(kwargs))
@@ -85,6 +82,21 @@ def __init__(self, user_id, project_id, is_admin=None, read_deleted="no",
         if overwrite or not hasattr(local.store, 'context'):
             self.update_store()
 
+    def _get_read_deleted(self):
+        return self._read_deleted
+
+    def _set_read_deleted(self, read_deleted):
+        if read_deleted not in ('no', 'yes', 'only'):
+            raise ValueError(_("read_deleted can only be one of 'no', "
+                               "'yes' or 'only', not %r") % read_deleted)
+        self._read_deleted = read_deleted
+
+    def _del_read_deleted(self):
+        del self._read_deleted
+
+    read_deleted = property(_get_read_deleted, _set_read_deleted,
+                            _del_read_deleted)
+
     def update_store(self):
         local.store.context = self
 

nova/tests/test_context.py

@@ -38,13 +38,23 @@ def test_request_context_read_deleted(self):
                                       read_deleted='yes')
         self.assertEquals(ctxt.read_deleted, 'yes')
 
+        ctxt.read_deleted = 'no'
+        self.assertEquals(ctxt.read_deleted, 'no')
+
     def test_request_context_read_deleted_invalid(self):
         self.assertRaises(ValueError,
                           context.RequestContext,
                           '111',
                           '222',
                           read_deleted=True)
 
+        ctxt = context.RequestContext('111', '222')
+        self.assertRaises(ValueError,
+                          setattr,
+                          ctxt,
+                          'read_deleted',
+                          True)
+
     def test_extra_args_to_context_get_logged(self):
         info = {}