askrht/order-demo

@Parent is not loaded even though it has @Load annotation. Here's the relevant code.

```
@Cache
@Entity
public class Order {
    @Id private Long id;
    @Parent @Load public Ref<Profile> profile;
    @Index private String title;
    @Load @Index List<Ref<Product>> products = new ArrayList<Ref<Product>>(10);
    Map<String, OrderedProduct> orderedProducts = new HashMap<String, OrderedProduct>(10);

    @SuppressWarnings("unused")
    private Order() {}
    
    public Order(final Profile profile,
                final OrderForm orderForm
            ) {
            this.profile = Ref.create(Key.create(Profile.class, profile.getUserId()));

```

Sample app to demo a @Load bug in objectify.

• git clone https://github.com/askrht/order-demo.git
• https://github.com/askrht/order-demo.git

One time setup only if you want to deploy to appengine

• Replace WEB_CLIENT_ID in Constants.java
• Replace conferencecentral2 in appengine-web.xml
• Replace conferencecentral2 in pom.xml

Maven commands

mvn clean install
mvn eclipse:clean
mvn eclipse:eclipse
mvn appengine:run

Steps To reproduce the problem

1. Execute mvn clean compile test. Notice that the OrderTest passes. It is able to read the Profile.
2. Go to api explorer at http://localhost:8080/_ah/explorer
3. Create a product with id a1 , no need to authenticate
4. Create an order, requires authentication, use this JSON { "orderQty": [ { "productId": "a1", "qty": "12" } ] }
5. You will see the following exception:

   java.io.IOException: com.fasterxml.jackson.databind.JsonMappingException: Direct self-reference leading to cycle (through reference chain: com.conferencecentral.api.domain.Order["profile"]->com.googlecode.objectify.impl.ref.LiveRef["key"]->com.googlecode.objectify.Key["root"])
   at com.google.api.server.spi.response.ServletResponseResultWriter.writeValueAsString(ServletResponseResultWriter.java:212)
   at com.google.api.server.spi.response.ServletResponseResultWriter.write(ServletResponseResultWriter.java:101)
   at com.google.api.server.spi.SystemService.invokeServiceMethod(SystemService.java:352)
   at com.google.api.server.spi.handlers.EndpointsMethodHandler$RestHandler.handle(EndpointsMethodHandler.java:119)
   at com.google.api.server.spi.handlers.EndpointsMethodHandler$RestHandler.handle(EndpointsMethodHandler.java:102)
   at com.google.api.server.spi.dispatcher.PathDispatcher.dispatch(PathDispatcher.java:50)
   at com.google.api.server.spi.EndpointsServlet.service(EndpointsServlet.java:71)
   at javax.servlet.http.HttpServlet.service(HttpServlet.java:790)
   at org.eclipse.jetty.servlet.ServletHolder.handle(ServletHolder.java:848)
   at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1772)
   at com.googlecode.objectify.ObjectifyFilter.doFilter(ObjectifyFilter.java:48)
   at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1759)
   at com.google.appengine.tools.development.ResponseRewriterFilter.doFilter(ResponseRewriterFilter.java:134)
   at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1759)
   at com.google.appengine.tools.development.HeaderVerificationFilter.doFilter(HeaderVerificationFilter.java:34)
   at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1759)
   at com.google.appengine.api.blobstore.dev.ServeBlobFilter.doFilter(ServeBlobFilter.java:63)
   at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1759)
   at com.google.apphosting.utils.servlet.TransactionCleanupFilter.doFilter(TransactionCleanupFilter.java:48)
   at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1759)
   at com.google.appengine.tools.development.jetty9.StaticFileFilter.doFilter(StaticFileFilter.java:123)
   at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1759)
   at com.google.appengine.tools.development.DevAppServerModulesFilter.doDirectRequest(DevAppServerModulesFilter.java:366)
   at com.google.appengine.tools.development.DevAppServerModulesFilter.doDirectModuleRequest(DevAppServerModulesFilter.java:349)
   at com.google.appengine.tools.development.DevAppServerModulesFilter.doFilter(DevAppServerModulesFilter.java:116)
   at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1759)
   at com.google.appengine.tools.development.DevAppServerRequestLogFilter.doFilter(DevAppServerRequestLogFilter.java:44)
   at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1751)
   at org.eclipse.jetty.servlet.ServletHandler.doHandle(ServletHandler.java:582)
   at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:143)
   at org.eclipse.jetty.security.SecurityHandler.handle(SecurityHandler.java:524)
   at org.eclipse.jetty.server.session.SessionHandler.doHandle(SessionHandler.java:226)
   at org.eclipse.jetty.server.handler.ContextHandler.doHandle(ContextHandler.java:1180)
   at org.eclipse.jetty.servlet.ServletHandler.doScope(ServletHandler.java:512)
   at org.eclipse.jetty.server.session.SessionHandler.doScope(SessionHandler.java:185)
   at org.eclipse.jetty.server.handler.ContextHandler.doScope(ContextHandler.java:1112)
   at com.google.appengine.tools.development.jetty9.DevAppEngineWebAppContext.doScope(DevAppEngineWebAppContext.java:94)
   at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:141)
   at org.eclipse.jetty.server.handler.HandlerWrapper.handle(HandlerWrapper.java:134)
   at com.google.appengine.tools.development.jetty9.JettyContainerService$ApiProxyHandler.handle(JettyContainerService.java:597)
   at org.eclipse.jetty.server.handler.HandlerWrapper.handle(HandlerWrapper.java:134)
   at org.eclipse.jetty.server.Server.handle(Server.java:534)
   at org.eclipse.jetty.server.HttpChannel.handle(HttpChannel.java:320)
   at org.eclipse.jetty.server.HttpConnection.onFillable(HttpConnection.java:251)
   at org.eclipse.jetty.io.AbstractConnection$ReadCallback.succeeded(AbstractConnection.java:283)
   at org.eclipse.jetty.io.FillInterest.fillable(FillInterest.java:108)
   at org.eclipse.jetty.io.SelectChannelEndPoint$2.run(SelectChannelEndPoint.java:93)
   at org.eclipse.jetty.util.thread.strategy.ExecuteProduceConsume.executeProduceConsume(ExecuteProduceConsume.java:303)
   at org.eclipse.jetty.util.thread.strategy.ExecuteProduceConsume.produceConsume(ExecuteProduceConsume.java:148)
   at org.eclipse.jetty.util.thread.strategy.ExecuteProduceConsume.run(ExecuteProduceConsume.java:136)
   at org.eclipse.jetty.util.thread.QueuedThreadPool.runJob(QueuedThreadPool.java:671)
   at org.eclipse.jetty.util.thread.QueuedThreadPool$2.run(QueuedThreadPool.java:589)
   at java.lang.Thread.run(Thread.java:745)
   

6. If we comment the following line in Order.java, the error will disappear but then the unit test will fail with a NullPointerException because the profile is not present.

   this.profile = Ref.create(Key.create(Profile.class, profile.getUserId()));
   

7. Execute order.queryOrdersByProductsAdmin, pass a1 as the product id and you will get the same error.