Cannot rollback a document to its first revision

        Error number 3201 in 3: Exception while saving document Main.WebHome
Wrapped Exception: a different object with the same identifier value was already associated with the session: [com.xpn.xwiki.doc.XWikiDocument#-114121954]
com.xpn.xwiki.XWikiException: Error number 3201 in 3: Exception while saving document Main.WebHome
Wrapped Exception: a different object with the same identifier value was already associated with the session: [com.xpn.xwiki.doc.XWikiDocument#-114121954]
	at com.xpn.xwiki.store.XWikiHibernateStore.saveXWikiDoc(XWikiHibernateStore.java:455)
	at com.xpn.xwiki.store.XWikiCacheStore.saveXWikiDoc(XWikiCacheStore.java:97)
	at com.xpn.xwiki.store.XWikiCacheStore.saveXWikiDoc(XWikiCacheStore.java:91)
	at com.xpn.xwiki.XWiki.saveDocument(XWiki.java:1077)
	at com.xpn.xwiki.XWiki.saveDocument(XWiki.java:1050)
	at com.xpn.xwiki.XWiki.rollback(XWiki.java:6101)
	at com.xpn.xwiki.web.RollbackAction.action(RollbackAction.java:59)
	at com.xpn.xwiki.web.XWikiAction.execute(XWikiAction.java:188)
	at org.apache.struts.action.RequestProcessor.processActionPerform(RequestProcessor.java:431)
	at org.apache.struts.action.RequestProcessor.process(RequestProcessor.java:236)
	at org.apache.struts.action.ActionServlet.process(ActionServlet.java:1196)
	at org.apache.struts.action.ActionServlet.doGet(ActionServlet.java:414)
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:596)
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:689)
	at org.mortbay.jetty.servlet.ServletHolder.handle(ServletHolder.java:428)
	at org.mortbay.jetty.servlet.WebApplicationHandler$CachedChain.doFilter(WebApplicationHandler.java:830)
	at com.xpn.xwiki.web.SetCharacterEncodingFilter.doFilter(SetCharacterEncodingFilter.java:117)
	at org.mortbay.jetty.servlet.WebApplicationHandler$CachedChain.doFilter(WebApplicationHandler.java:821)
	at org.mortbay.jetty.servlet.WebApplicationHandler.dispatch(WebApplicationHandler.java:471)
	at org.mortbay.jetty.servlet.ServletHandler.handle(ServletHandler.java:568)
	at org.mortbay.http.HttpContext.handle(HttpContext.java:1565)
	at org.mortbay.jetty.servlet.WebApplicationContext.handle(WebApplicationContext.java:633)
	at org.mortbay.http.HttpContext.handle(HttpContext.java:1517)
	at org.mortbay.http.HttpServer.service(HttpServer.java:954)
	at org.mortbay.http.HttpConnection.service(HttpConnection.java:816)
	at org.mortbay.http.HttpConnection.handleNext(HttpConnection.java:983)
	at org.mortbay.http.HttpConnection.handle(HttpConnection.java:833)
	at org.mortbay.http.SocketListener.handleConnection(SocketListener.java:244)
	at org.mortbay.util.ThreadedServer.handle(ThreadedServer.java:357)
	at org.mortbay.util.ThreadPool$PoolThread.run(ThreadPool.java:534)


Wrapped Exception:

org.hibernate.NonUniqueObjectException: a different object with the same identifier value was already associated with the session: [com.xpn.xwiki.doc.XWikiDocument#-114121954]
	at org.hibernate.engine.StatefulPersistenceContext.checkUniqueness(StatefulPersistenceContext.java:590)
	at org.hibernate.event.def.DefaultSaveOrUpdateEventListener.performUpdate(DefaultSaveOrUpdateEventListener.java:284)
	at org.hibernate.event.def.DefaultSaveOrUpdateEventListener.entityIsDetached(DefaultSaveOrUpdateEventListener.java:223)
	at org.hibernate.event.def.DefaultUpdateEventListener.performSaveOrUpdate(DefaultUpdateEventListener.java:33)
	at org.hibernate.event.def.DefaultSaveOrUpdateEventListener.onSaveOrUpdate(DefaultSaveOrUpdateEventListener.java:70)
	at org.hibernate.impl.SessionImpl.fireUpdate(SessionImpl.java:564)
	at org.hibernate.impl.SessionImpl.update(SessionImpl.java:552)
	at org.hibernate.impl.SessionImpl.update(SessionImpl.java:544)
	at com.xpn.xwiki.store.XWikiHibernateStore.saveXWikiDoc(XWikiHibernateStore.java:360)
	at com.xpn.xwiki.store.XWikiCacheStore.saveXWikiDoc(XWikiCacheStore.java:97)
	at com.xpn.xwiki.store.XWikiCacheStore.saveXWikiDoc(XWikiCacheStore.java:91)
	at com.xpn.xwiki.XWiki.saveDocument(XWiki.java:1077)
	at com.xpn.xwiki.XWiki.saveDocument(XWiki.java:1050)
	at com.xpn.xwiki.XWiki.rollback(XWiki.java:6101)
	at com.xpn.xwiki.web.RollbackAction.action(RollbackAction.java:59)
	at com.xpn.xwiki.web.XWikiAction.execute(XWikiAction.java:188)
	at org.apache.struts.action.RequestProcessor.processActionPerform(RequestProcessor.java:431)
	at org.apache.struts.action.RequestProcessor.process(RequestProcessor.java:236)
	at org.apache.struts.action.ActionServlet.process(ActionServlet.java:1196)
	at org.apache.struts.action.ActionServlet.doGet(ActionServlet.java:414)
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:596)
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:689)
	at org.mortbay.jetty.servlet.ServletHolder.handle(ServletHolder.java:428)
	at org.mortbay.jetty.servlet.WebApplicationHandler$CachedChain.doFilter(WebApplicationHandler.java:830)
	at com.xpn.xwiki.web.SetCharacterEncodingFilter.doFilter(SetCharacterEncodingFilter.java:117)
	at org.mortbay.jetty.servlet.WebApplicationHandler$CachedChain.doFilter(WebApplicationHandler.java:821)
	at org.mortbay.jetty.servlet.WebApplicationHandler.dispatch(WebApplicationHandler.java:471)
	at org.mortbay.jetty.servlet.ServletHandler.handle(ServletHandler.java:568)
	at org.mortbay.http.HttpContext.handle(HttpContext.java:1565)
	at org.mortbay.jetty.servlet.WebApplicationContext.handle(WebApplicationContext.java:633)
	at org.mortbay.http.HttpContext.handle(HttpContext.java:1517)
	at org.mortbay.http.HttpServer.service(HttpServer.java:954)
	at org.mortbay.http.HttpConnection.service(HttpConnection.java:816)
	at org.mortbay.http.HttpConnection.handleNext(HttpConnection.java:983)
	at org.mortbay.http.HttpConnection.handle(HttpConnection.java:833)
	at org.mortbay.http.SocketListener.handleConnection(SocketListener.java:244)
	at org.mortbay.util.ThreadedServer.handle(ThreadedServer.java:357)
	at org.mortbay.util.ThreadPool$PoolThread.run(ThreadPool.java:534)