RHNS 5.3.1 generates traceback "query did not return a unique result"

Issue

• Kickstarting a system from a RHEL 5u5 tree fails while downloading packages

• An email is received indicating a traceback occurred (and the traceback is also seen in the catalina log):

  > The following exception occurred while executing this request:
  > GET /rhn/common/DownloadFile.do
  >
  > Date:6/24/10 1:29:31 AM EDT
  > Headers:
  >  host: sat.example.com
  >  user-agent: ELinks/0.11.1 (textmode; Linux; -)
  >  accept: */*
  >  accept-encoding: gzip
  >  accept-language: en
  >  X-Forwarded-For: 10.73.61.171
  >  X-Forwarded-Host: sat.example.com
  >  X-Forwarded-Server: sat.example.com
  >  connection: Keep-Alive
  >
  > Request:
  > Local Name = sat.example.com
  > Server Name = sat.example.com
  > Requested Session Valid = false
  > Session = org.apache.catalina.session.StandardSessionFacade@1b7b1b7b[session=StandardSession[32BD0D1636ECFAE2B05856A074ABABEE]]
  > Protocol = http
  > Request Locale = en_US
  > Request Character Encoding = UTF-8
  > Attribute Names = rhnActiveLang, javax.servlet.jsp.jstl.fmt.timeZone.request, __sitemesh__filterapplied, org.apache.struts.action.MESSAGE, session, org.apache.struts.action.mapping.instance, requestedUri, org.apache.struts.action.MODULE,
  >
  >
  > User Information:
  > No User logged in.
  >
  > Exception:
  > javax.servlet.ServletException: query did not return a unique result: 2
  > at org.apache.struts.action.RequestProcessor.processException(RequestProcessor.java:535)
  > at org.apache.struts.action.RequestProcessor.processActionPerform(RequestProcessor.java:433)
  > at org.apache.struts.action.RequestProcessor.process(RequestProcessor.java:237)
  > at com.redhat.rhn.frontend.struts.RhnRequestProcessor.process(RhnRequestProcessor.java:82)
  > 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:690)
  > at javax.servlet.http.HttpServlet.service(HttpServlet.java:803)
  > at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:269)
  > at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:188)
  > at com.redhat.rhn.frontend.servlets.AuthFilter.doFilter(AuthFilter.java:73)
  > at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:215)
  > at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:188)
  > at com.opensymphony.module.sitemesh.filter.PageFilter.parsePage(PageFilter.java:142)
  > at com.opensymphony.module.sitemesh.filter.PageFilter.doFilter(PageFilter.java:58)
  > at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:215)
  > at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:188)
  > at com.redhat.rhn.frontend.servlets.LocalizedEnvironmentFilter.doFilter(LocalizedEnvironmentFilter.java:67)
  > at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:215)
  > at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:188)
  > at com.redhat.rhn.frontend.servlets.EnvironmentFilter.doFilter(EnvironmentFilter.java:108)
  > at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:215)
  > at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:188)
  > at com.redhat.rhn.frontend.servlets.SessionFilter.doFilter(SessionFilter.java:55)
  > at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:215)
  > at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:188)
  > at com.redhat.rhn.frontend.servlets.SetCharacterEncodingFilter.doFilter(SetCharacterEncodingFilter.java:97)
  > at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:215)
  > at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:188)
  > at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:210)
  > at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:172)
  > at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:127)
  > at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:117)
  > at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:108)
  > at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:151)
  > at org.apache.jk.server.JkCoyoteHandler.invoke(JkCoyoteHandler.java:200)
  > at org.apache.jk.common.HandlerRequest.invoke(HandlerRequest.java:291)
  > at org.apache.jk.common.ChannelSocket.invoke(ChannelSocket.java:775)
  > at org.apache.jk.common.ChannelSocket.processConnection(ChannelSocket.java:704)
  > at org.apache.jk.common.ChannelSocket$SocketConnection.runIt(ChannelSocket.java:897)
  > at org.apache.tomcat.util.threads.ThreadPool$ControlRunnable.run(ThreadPool.java:685)
  > at java.lang.Thread.run(Thread.java:736)
  > Caused by: org.hibernate.NonUniqueResultException: query did not return a unique result: 2
  > at org.hibernate.impl.AbstractQueryImpl.uniqueElement(AbstractQueryImpl.java:820)
  > at org.hibernate.impl.AbstractQueryImpl.uniqueResult(AbstractQueryImpl.java:811)
  > at com.redhat.rhn.domain.kickstart.KickstartFactory.lookupKickstartTreeByLabel(KickstartFactory.java:522)
  > at com.redhat.rhn.frontend.action.common.DownloadFile.handleKickstartDownload(DownloadFile.java:220)
  > at com.redhat.rhn.frontend.action.common.DownloadFile.execute(DownloadFile.java:100)
  > at org.apache.struts.action.RequestProcessor.processActionPerform(RequestProcessor.java:431)
  > ... 40 more
  >