impl/memory: Disallow empty namespace.

filter/dscache/context.go

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 package dscache
 
 import (
         ds "github.com/luci/gae/service/datastore"
         "github.com/luci/gae/service/info"
         mc "github.com/luci/gae/service/memcache"
@@ skipping 28 matching lines @@
         return AlwaysFilterRDS(c, shardsForKey)
 }
 
 // AlwaysFilterRDS installs a caching RawDatastore filter in the context.
 //
 // Unlike FilterRDS it doesn't check GlobalConfig via IsGloballyEnabled call,
 // assuming caller already knows whether filter should be applied or not.
 func AlwaysFilterRDS(c context.Context, shardsForKey func(*ds.Key) int) context.Context {
         return ds.AddRawFilters(c, func(c context.Context, ds ds.RawInterface) ds.RawInterface {
                 i := info.Get(c)
+                ns, _ := i.GetNamespace()
 
                 sc := &supportContext{
                         i.AppID(),
-                        i.GetNamespace(),
+                        ns,
                         c,
                         mc.Get(c),
                         mathrand.Get(c),
                         shardsForKey,
                 }
 
                 v := c.Value(dsTxnCacheKey)
                 if v == nil {
                         return &dsCache{ds, sc}
                 }
                 return &dsTxnCache{ds, v.(*dsTxnState), sc}
         })
 }