<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; }
}
</style>
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<td bgcolor="#3e4c4e" style="background-color:#3e4c4e;color:#ffffff;font-family:Arial,FreeSans,Helvetica,sans-serif;font-size:12px;line-height:1;"><img src="https://www.jboss.org/dms/hibernate/images/jira/jiraheader_hibernate.png" alt="" style="vertical-align:top;" /></td>
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<img id="email-avatar" src="https://hibernate.onjira.com/secure/useravatar?ownerId=steve&avatarId=10346" alt="" height="48" width="48" border="0" align="left" style="padding:0;margin: 0 16px 16px 0;" />
<div id="email-action" style="padding: 0 0 8px 0;font-size:12px;line-height:18px;">
<a class="user-hover" rel="steve" id="email_steve" href="https://hibernate.onjira.com/secure/ViewProfile.jspa?name=steve" style="color:#6c797f;">Steve Ebersole</a>
commented on <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-7928'>HHH-7928</a>
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<div id="email-summary" style="font-size:16px;line-height:20px;padding:2px 0 16px 0;">
<a style='color:#6c797f;text-decoration:none;' href='https://hibernate.onjira.com/browse/HHH-7928'><strong>Regression caused by HHH-6361</strong></a>
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<div class="comment-block" style="background-color:#edf5ff;border:1px solid #dddddd;color:#000000;padding:12px;"><p>Ok, I found the where/why this happens. It comes from the <tt>CollectionEntry#resetStoredSnapshot</tt> method added as part of <a href="https://hibernate.onjira.com/browse/HHH-6361" title="Collection events may contain wrong stored snapshot after merging a detached entity into the persistencecontext"><del>HHH-6361</del></a>:</p>
<div class="code panel" style="border-style: solid;border-width: 1px;"><div class="codeContent panelContent">
<pre class="code-java"><span class="code-keyword">public</span> void resetStoredSnapshot(PersistentCollection collection, Serializable storedSnapshot) {
LOG.debugf(<span class="code-quote">"Reset storedSnapshot to %s <span class="code-keyword">for</span> %s"</span>, storedSnapshot, <span class="code-keyword">this</span>);
snapshot = storedSnapshot;
collection.setSnapshot(loadedKey, role, snapshot);
}</pre>
</div></div>
<p>So in the stated use case what is happening is that this <tt>CollectionEntry</tt>, as well as the incoming {collection}} reference, refer to the managed (previously merged) graph. However, the incoming <tt>storedSnapshot</tt> reference is coming from the original detached graph. Since that original graph had an empty snapshot, the net effect here is to overwrite the managed snapshot state with the empty thus all the entries are re-inserted into the database.</p>
<p>Still thinking through the best solution. I think the most appropriate solution will be to have <tt>CollectionEntry</tt> (and <tt>EntityEntry</tt> too?) keep track of a flag denoting whether they came about from a merge. In cases where that is true, we can skip the <tt>resetStoredSnapshot</tt> processing.</p></div>
<div style="color:#505050;padding:4px 0 0 0;"> </div>
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