Fix miscellaneous prod bugs.

service/datastore/pls_impl.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.
 
 // HEAVILY adapted from github.com/golang/appengine/datastore
 
 package datastore
 
 import (
         "fmt"
@@ skipping 232 matching lines @@
                         val, err := p.GetMeta(k)
                         if err != nil {
                                 return nil, err // TODO(riannucci): should these be ignored?
                         }
                         p := Property{}
                         if err = p.SetValue(val, NoIndex); err != nil {
                                 return nil, err
                         }
                         ret["$"+k] = []Property{p}
                 }
+                if _, ok := p.c.byMeta["kind"]; !ok {
+                        ret["$kind"] = []Property{MkProperty(p.getDefaultKind())}
+                }
         }
         return ret, nil
 }
 
+func (p *structPLS) getDefaultKind() string {
+        return p.o.Type().Name()
+}
+
 func (p *structPLS) save(propMap PropertyMap, prefix string, is IndexSetting) (idxCount int, err error) {
         if err = p.Problem(); err != nil {
                 return
         }
 
         saveProp := func(name string, si IndexSetting, v reflect.Value, st *structTag) (err error) {
                 if st.substructCodec != nil {
                         count, err := (&structPLS{v, st.substructCodec}).save(propMap, name, si)
                         if err == nil {
                                 idxCount += count
@@ skipping 50 matching lines @@
         }
         return
 }
 
 func (p *structPLS) GetMeta(key string) (interface{}, error) {
         if err := p.Problem(); err != nil {
                 return nil, err
         }
         idx, ok := p.c.byMeta[key]
         if !ok {
+                if key == "kind" {
+                        return p.getDefaultKind(), nil
+                }
                 return nil, ErrMetaFieldUnset
         }
         st := p.c.byIndex[idx]
         val := st.metaVal
         f := p.o.Field(idx)
         if st.canSet {
                 if !reflect.DeepEqual(reflect.Zero(f.Type()).Interface(), f.Interface()) {
                         val = f.Interface()
                         if bf, ok := val.(Toggle); ok {
                                 val = bf == On // true if On, otherwise false
@@ skipping 248 matching lines @@
                 switch val {
                 case "on", "On", "true":
                         return true, nil
                 case "off", "Off", "false":
                         return false, nil
                 }
                 return nil, fmt.Errorf("Toggle field has bad/missing default, got %q", val)
         }
         return nil, fmt.Errorf("helper: meta field with bad type/value %s/%q", t, val)
 }