<style>
/* Changing the layout to use less space for mobiles */
@media screen and (max-device-width: 480px), screen and (-webkit-min-device-pixel-ratio: 2) {
    #email-body { min-width: 30em !important; }
    #email-page { padding: 8px !important; }
    #email-banner { padding: 8px 8px 0 8px !important; }
    #email-avatar { margin: 1px 8px 8px 0 !important; padding: 0 !important; }
    #email-fields { padding: 0 8px 8px 8px !important; }
    #email-gutter { width: 0 !important; }
}
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                                    <a class="user-hover" rel="adar" id="email_adar" href="https://hibernate.onjira.com/secure/ViewProfile.jspa?name=adar" style="color:#6c797f;">Adar Dembo</a>
     created <img src="https://hibernate.onjira.com/images/icons/bug.gif" height="16" width="16" border="0" align="absmiddle" alt="Bug"> <a style='color:#6c797f;text-decoration:none;' href='https://hibernate.onjira.com/browse/HHH-8057'>HHH-8057</a>
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                <a style='color:#6c797f;text-decoration:none;' href='https://hibernate.onjira.com/browse/HHH-8057'><strong>Bad proxy behavior when using store_data_at_delete and audited parent/child relationships</strong></a>
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        <strong style="font-weight:normal;color:#505050;">Issue Type:</strong>
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                <img src="https://hibernate.onjira.com/images/icons/bug.gif" height="16" width="16" border="0" align="absmiddle" alt="Bug">        Bug
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        <strong style="font-weight:normal;color:#505050;">Assignee:</strong>
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                    Unassigned            </td>
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        <strong style="font-weight:normal;color:#505050;">Components:</strong>
    </td>
    <td style="color:#000000;font-family:Arial,FreeSans,Helvetica,sans-serif;font-size:12px;padding:0 0 10px 0;width:100%;">
                    envers            </td>
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        <strong style="font-weight:normal;color:#505050;">Created:</strong>
    </td>
    <td style="color:#000000;font-family:Arial,FreeSans,Helvetica,sans-serif;font-size:12px;padding:0 0 10px 0;width:100%;">
        08/Mar/13 1:20 AM
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        <strong style="font-weight:normal;color:#505050;">Description:</strong>
    </td>
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        <p style='margin-top:0;margin-bottom:10px;'>Use hibernate.envers.store_data_at_delete = true</p>

<div class="code panel" style="border-width: 1px;"><div class="codeContent panelContent">
<pre class="code-java">class Parent {
  @Audited
  <span class="code-object">String</span> name;

  Set&lt;Child&gt; children;
}

class Child {
  @Audited
  <span class="code-object">String</span> name;

  @Audited
  Parent parent;

  <span class="code-keyword">public</span> <span class="code-object">int</span> hashCode() {
    <span class="code-keyword">return</span> Objects.hashCode(name, parent);
  }
}</pre>
</div></div>

<p style='margin-top:0;margin-bottom:10px;'>Transaction 1:<br/>
Creates a parent.<br/>
Creates a child for it.</p>

<p style='margin-top:0;margin-bottom:10px;'>You get one revision, one Parent_AUD (create), and one Child_AUD (create).</p>

<p style='margin-top:0;margin-bottom:10px;'>Transaction 2:<br/>
Deletes the parent.<br/>
Deletes the child. In my case, this is via cascade.</p>

<p style='margin-top:0;margin-bottom:10px;'>You get one revision, one Parent_AUD (delete), and one Child_AUD (delete).</p>

<p style='margin-top:0;margin-bottom:10px;'>Transaction 3:<br/>
Lookup using the following code:</p>

<div class="code panel" style="border-width: 1px;"><div class="codeContent panelContent">
<pre class="code-java">AuditReaderFactory.get(em)
.createQuery()
.forRevisionsOfEntity(Child.class, <span class="code-keyword">true</span>, <span class="code-keyword">true</span>)
.getResultList();</pre>
</div></div> 

<p style='margin-top:0;margin-bottom:10px;'>This throws an exception:</p>

<div class="preformatted panel" style="border-width: 1px;"><div class="preformattedContent panelContent">
<pre>javax.persistence.EntityNotFoundException: Unable to find com.cloudera.cmf.model.DbService with id 1
          at org.hibernate.ejb.Ejb3Configuration$Ejb3EntityNotFoundDelegate.handleEntityNotFound(Ejb3Configuration.java:155)
          at org.hibernate.proxy.AbstractLazyInitializer.checkTargetState(AbstractLazyInitializer.java:171)
          at org.hibernate.proxy.AbstractLazyInitializer.initialize(AbstractLazyInitializer.java:160)
          at org.hibernate.proxy.AbstractLazyInitializer.getImplementation(AbstractLazyInitializer.java:195)
          at org.hibernate.proxy.pojo.javassist.JavassistLazyInitializer.invoke(JavassistLazyInitializer.java:185)
          at Parent_$$_javassist_2.hashCode(Parent_$$_javassist_2.java)
          at java.util.Arrays.hashCode(Arrays.java:3655)
          at com.google.common.base.Objects.hashCode(Objects.java:77)
          at Child.hashCode(Child.java:385)
          at org.hibernate.envers.tools.Triple.hashCode(Triple.java:74)
          at java.util.HashMap.put(HashMap.java:372)
          at org.hibernate.envers.reader.FirstLevelCache.putOnEntityNameCache(FirstLevelCache.java:87)
          at org.hibernate.envers.entities.EntityInstantiator.createInstanceFromVersionsEntity(EntityInstantiator.java:104)
          at org.hibernate.envers.query.impl.RevisionsOfEntityQuery.list(RevisionsOfEntityQuery.java:134)
          at org.hibernate.envers.query.impl.AbstractAuditQuery.getResultList(AbstractAuditQuery.java:105)
          ...
</pre>
</div></div>

<p style='margin-top:0;margin-bottom:10px;'>When store_data_at_delete is true, the second Child_AUD entry contains a link to Parent_AUD, instead of a NULL. The audit query tries to build Child entities out of the two Child_AUD entries but fails for the second one. Why does it fail? Because the SQL query it uses to fetch the correct Parent_AUD entry ignores entries with revision type DEL. Here's the corresponding comment from EntitiesAtRevisionQuery.list():</p>

<div class="code panel" style="border-width: 1px;"><div class="codeContent panelContent">
<pre class="code-java">/*
         * The query that we need to create:
         *   SELECT <span class="code-keyword">new</span> list(e) FROM versionsReferencedEntity e
         *   WHERE
         * (all specified conditions, transformed, on the <span class="code-quote">"e"</span> entity) AND
         * (selecting e entities at revision :revision)
         *   --&gt; <span class="code-keyword">for</span> DefaultAuditStrategy:
         *     e.revision = (SELECT max(e2.revision) FROM versionsReferencedEntity e2
         *       WHERE e2.revision &lt;= :revision AND e2.id = e.id) 
         *     
         *   --&gt; <span class="code-keyword">for</span> ValidityAuditStrategy:
         *     e.revision &lt;= :revision and (e.endRevision &gt; :revision or e.endRevision is <span class="code-keyword">null</span>)
         *     
         *     AND
         * (only non-deleted entities)
         *     e.revision_type != DEL
         */</pre>
</div></div>

<p style='margin-top:0;margin-bottom:10px;'>I think the right thing to do here is relax that last condition when we're fetching a relation for a DEL audit entry.</p>

<p style='margin-top:0;margin-bottom:10px;'>Here's the corresponding forum post: <a href="https://community.jboss.org/message/800890">https://community.jboss.org/message/800890</a></p>
    </td>
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        <strong style="font-weight:normal;color:#505050;">Project:</strong>
    </td>
    <td style="color:#000000;font-family:Arial,FreeSans,Helvetica,sans-serif;font-size:12px;padding:0 0 10px 0;width:100%;">
        <a style="color:#6c797f;" href="https://hibernate.onjira.com/browse/HHH">Hibernate ORM</a>
    </td>
</tr>                                                <tr valign="top">
    <td style="color:#000000;font-family:Arial,FreeSans,Helvetica,sans-serif;font-size:12px;padding:0 10px 10px 0;white-space:nowrap;">
        <strong style="font-weight:normal;color:#505050;">Priority:</strong>
    </td>
    <td style="color:#000000;font-family:Arial,FreeSans,Helvetica,sans-serif;font-size:12px;padding:0 0 10px 0;width:100%;">
                <img src="https://hibernate.onjira.com/images/icons/priority_major.gif" height="16" width="16" border="0" align="absmiddle" alt="Major">        Major
    </td>
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        <strong style="font-weight:normal;color:#505050;">Reporter:</strong>
    </td>
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