Detect cyclic references (@Embedded) [moved]

[jyemin]

This is Issue 47 moved from a Google Code project.
Added by 2010-05-16T12:45:04.000Z by google-a...@codesmell.de.
Please review that bug for more context and additional comments, but update this bug.

Original labels: Type-Enhancement, Priority-Low, Milestone-Icebox

Original description

When embedding an Entity, that itself has a reference to the root Entity,
Morphia (reasonably) produces a StackOverflow.

Don´t know if this easy to detect, so i´d call this a minor issue.

<b>What steps will reproduce the problem?</b>
1. run attached TestCase

<b>What version of the product are you using? On what operating system?</b>
0.93-SNAPSHOT

java.lang.StackOverflowError
    at java.util.HashMap$Entry.<init>(Unknown Source)
    at java.util.LinkedHashMap$Entry.<init>(Unknown Source)
    at java.util.LinkedHashMap.createEntry(Unknown Source)
    at java.util.LinkedHashMap.addEntry(Unknown Source)
    at java.util.HashMap.put(Unknown Source)
    at com.mongodb.BasicDBObject.put(BasicDBObject.java:153)
    at com.google.code.morphia.mapping.Mapper.mapValuesToDBObject(Mapper.java:467)
    at com.google.code.morphia.mapping.Mapper.toDBObject(Mapper.java:282)
    at
com.google.code.morphia.mapping.Mapper.mapEmbeddedToDBObject(Mapper.java:375)
    at com.google.code.morphia.mapping.Mapper.toDBObject(Mapper.java:280)

...

[evanchooly]

While it's possible to fix the code to deal with this case, there's no support for intra-document references in bson. Until there is, this use case will be unsupported in morphia as well.