[Building Sakai] Calendar tool getting stuck (nonterminating loop)

[Matthew Buckett]

We're seeing an issue with the calendar tool (2.6.x) where for some
users the tool gets stuck in an infinite loop, I got to the bottom of
what is happening yet but wondered if anyone else had exprienced this.
I think it's related to subscriptions to external calendars from iCal
files but don't have a good way to reproduce it at the moment.

The stuck threads have call stacks like this:

@400000004e94183a1009e754 	at java.util.Vector.add(Vector.java:760)
@400000004e94183a100a3d44 	at
org.sakaiproject.calendar.tool.CalendarAction.getNewEvents(CalendarAction.java:3330)
@400000004e94183a100a9b04 	at
org.sakaiproject.calendar.tool.CalendarAction.buildWeekContext(CalendarAction.java:3753)
@400000004e94183a100af0f4 	at
org.sakaiproject.calendar.tool.CalendarAction.buildMainPanelContext(CalendarAction.java:2379)
@400000004e94183a100b4acc 	at
sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
@400000004e94183a100b9cd4 	at
sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
@400000004e94183a100bf2c4 	at
sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
@400000004e94183a100c8734 	at java.lang.reflect.Method.invoke(Method.java:597)
@400000004e94183a100cd93c 	at
org.sakaiproject.cheftool.VelocityPortletPaneledAction.toolModeDispatch(VelocityPortletPaneledAction.java:401)
@400000004e94183a100d2f2c 	at
org.sakaiproject.cheftool.ToolServlet.doGet(ToolServlet.java:227)
@400000004e94183a100d851c 	at
org.sakaiproject.cheftool.VelocityPortletPaneledAction.doGet(VelocityPortletPaneledAction.java:1014)
@400000004e94183a100dd724 	at
javax.servlet.http.HttpServlet.service(HttpServlet.java:627)
@400000004e94183a100e292c 	at
org.sakaiproject.vm.ComponentServlet.service(ComponentServlet.java:56)
@400000004e94183a100e7b34 	at
javax.servlet.http.HttpServlet.service(HttpServlet.java:729)
@400000004e94183a100ecd3c 	at
org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:269)
@400000004e94183a100f1f44 	at
org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:188)
@400000004e94183a100f7534 	at
org.sakaiproject.util.RequestFilter.doFilter(RequestFilter.java:586)
@400000004e94183a100fcb24 	at
org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:215)
@400000004e94183a10102114 	at
org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:188)
@400000004e94183a10107704 	at
org.apache.catalina.core.ApplicationDispatcher.invoke(ApplicationDispatcher.java:659)
@400000004e94183a1010c524 	at
org.apache.catalina.core.ApplicationDispatcher.processRequest(ApplicationDispatcher.java:457)
@400000004e94183a10111b14 	at
org.apache.catalina.core.ApplicationDispatcher.doForward(ApplicationDispatcher.java:359)
@400000004e94183a10116d1c 	at
org.apache.catalina.core.ApplicationDispatcher.forward(ApplicationDispatcher.java:311)
@400000004e94183a1011c30c 	at
org.sakaiproject.tool.impl.ActiveToolComponent$MyActiveTool.forward(ActiveToolComponent.java:479)
@400000004e94183a101218fc 	at
org.sakaiproject.portal.charon.SkinnableCharonPortal.forwardTool(SkinnableCharonPortal.java:1246)
@400000004e94183a10126eec 	at
org.sakaiproject.portal.charon.handlers.HierarchyToolHandler.doTool(HierarchyToolHandler.java:137)
@400000004e94183a1012c4dc 	at
org.sakaiproject.portal.charon.handlers.ToolHandler.doGet(ToolHandler.java:94)
@400000004e94183a101316e4 	at
org.sakaiproject.portal.charon.SkinnableCharonPortal.doGet(SkinnableCharonPortal.java:778)
@400000004e94183a101368ec 	at
javax.servlet.http.HttpServlet.service(HttpServlet.java:627)
@400000004e94183a1013baf4 	at
javax.servlet.http.HttpServlet.service(HttpServlet.java:729)
@400000004e94183a101410e4 	at
org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:269)
@400000004e94183a101462ec 	at
org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:188)
@400000004e94183a1014b4f4 	at
org.sakaiproject.util.OptimisticLogin.doFilter(OptimisticLogin.java:66)
@400000004e94183a10150ae4 	at
org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:215)
@400000004e94183a101560d4 	at
org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:188)
@400000004e94183a1015b2dc 	at
org.sakaiproject.util.RequestFilter.doFilter(RequestFilter.java:637)
@400000004e94183a101604e4 	at
org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:215)
@400000004e94183a10165ad4 	at
org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:188)
@400000004e94183a1016b0c4 	at
org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:213)
@400000004e94183a101702cc 	at
org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:172)
@400000004e94183a101758bc 	at
org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:127)
@400000004e94183a1017aac4 	at
org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:117)
@400000004e94183a1017fccc 	at
org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:581)
@400000004e94183a1018990c 	at
org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:108)
@400000004e94183a1018eefc 	at
org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:174)
@400000004e94183a10194104 	at
org.apache.jk.server.JkCoyoteHandler.invoke(JkCoyoteHandler.java:200)
@400000004e94183a1019930c 	at
org.apache.jk.common.HandlerRequest.invoke(HandlerRequest.java:291)
@400000004e94183a1019e514 	at
org.apache.jk.common.ChannelSocket.invoke(ChannelSocket.java:775)
@400000004e94183a101a3b04 	at
org.apache.jk.common.ChannelSocket.processConnection(ChannelSocket.java:704)
@400000004e94183a101a8d0c 	at
org.apache.jk.common.ChannelSocket$SocketConnection.runIt(ChannelSocket.java:897)
@400000004e94183a101aeeb4 	at
org.apache.tomcat.util.threads.ThreadPool$ControlRunnable.run(ThreadPool.java:689)
@400000004e94183a101b40bc 	at java.lang.Thread.run(Thread.java:662)


-- 
  Matthew Buckett
  VLE Developer, LTG, Oxford University Computing Services