Deletion of file variable breaks history detail/optimize rest endpoint

• given:
  • I start a process instance with a file variable
  • The process instance is pending in a wait state
  • I remove the file variable
• when:
  • I retrieve the historic details via REST-API or variable updates via optimize REST-API endpoint
• then:
  • I get an error message as a response with status code 500
• expected:
  • I can retrieve variable updates even if a file variable was removed

Hint:

• This is the error message you get:

  [7/30/18 8:46:45:218 CEST] 000002d5 0(id=121)]    W org.apache.cxf.phase.PhaseInterceptorChain doDefaultLogging Application {http://impl.rest.engine.bpm.camunda.org/}NamedProcessEngineRestServiceImpl has thrown exception, unwinding now
                                   org.apache.cxf.interceptor.Fault: UTILS-02001 Parameter 'filename' is null
          at org.apache.cxf.service.invoker.AbstractInvoker.createFault(AbstractInvoker.java:163)
          at org.apache.cxf.service.invoker.AbstractInvoker.invoke(AbstractInvoker.java:129)
          at com.ibm.ws.jaxrs20.server.LibertyJaxRsInvoker.invoke(LibertyJaxRsInvoker.java:174)
          at org.apache.cxf.jaxrs.JAXRSInvoker.invoke(JAXRSInvoker.java:200)
          at com.ibm.ws.jaxrs20.server.LibertyJaxRsInvoker.invoke(LibertyJaxRsInvoker.java:346)
          at org.apache.cxf.jaxrs.JAXRSInvoker.invoke(JAXRSInvoker.java:271)
          at com.ibm.ws.jaxrs20.server.LibertyJaxRsInvoker.invoke(LibertyJaxRsInvoker.java:346)
          at org.apache.cxf.jaxrs.JAXRSInvoker.invoke(JAXRSInvoker.java:99)
          at org.apache.cxf.interceptor.ServiceInvokerInterceptor$1.run(ServiceInvokerInterceptor.java:61)
          at org.apache.cxf.interceptor.ServiceInvokerInterceptor.handleMessage(ServiceInvokerInterceptor.java:99)
          at org.apache.cxf.phase.PhaseInterceptorChain.doIntercept(PhaseInterceptorChain.java:307)
          at org.apache.cxf.transport.ChainInitiationObserver.onMessage(ChainInitiationObserver.java:121)
          at org.apache.cxf.transport.http.AbstractHTTPDestination.invoke(AbstractHTTPDestination.java:256)
          at com.ibm.ws.jaxrs20.endpoint.AbstractJaxRsWebEndpoint.invoke(AbstractJaxRsWebEndpoint.java:147)
          at com.ibm.websphere.jaxrs.server.IBMRestServlet.handleRequest(IBMRestServlet.java:187)
          at com.ibm.websphere.jaxrs.server.IBMRestServlet.doGet(IBMRestServlet.java:153)
          at javax.servlet.http.HttpServlet.service(HttpServlet.java:687)
          at com.ibm.websphere.jaxrs.server.IBMRestServlet.service(IBMRestServlet.java:133)
          at com.ibm.ws.webcontainer.servlet.ServletWrapper.service(ServletWrapper.java:1235)
          at com.ibm.ws.webcontainer.servlet.ServletWrapper.handleRequest(ServletWrapper.java:779)
          at com.ibm.ws.webcontainer.servlet.ServletWrapper.handleRequest(ServletWrapper.java:478)
          at com.ibm.ws.webcontainer.servlet.ServletWrapperImpl.handleRequest(ServletWrapperImpl.java:178)
          at com.ibm.ws.webcontainer.filter.WebAppFilterChain.invokeTarget(WebAppFilterChain.java:143)
          at com.ibm.ws.webcontainer.filter.WebAppFilterChain.doFilter(WebAppFilterChain.java:96)
          at org.camunda.bpm.engine.rest.security.auth.ProcessEngineAuthenticationFilter.doFilter(ProcessEngineAuthenticationFilter.java:151)
          at com.ibm.ws.webcontainer.filter.FilterInstanceWrapper.doFilter(FilterInstanceWrapper.java:197)
          at com.ibm.ws.webcontainer.filter.WebAppFilterChain.doFilter(WebAppFilterChain.java:90)
          at org.camunda.bpm.engine.rest.filter.CacheControlFilter.doFilter(CacheControlFilter.java:41)
          at com.ibm.ws.webcontainer.filter.FilterInstanceWrapper.doFilter(FilterInstanceWrapper.java:197)
          at com.ibm.ws.webcontainer.filter.WebAppFilterChain.doFilter(WebAppFilterChain.java:90)
          at org.camunda.bpm.engine.rest.filter.EmptyBodyFilter.doFilter(EmptyBodyFilter.java:97)
          at com.ibm.ws.webcontainer.filter.FilterInstanceWrapper.doFilter(FilterInstanceWrapper.java:197)
          at com.ibm.ws.webcontainer.filter.WebAppFilterChain.doFilter(WebAppFilterChain.java:90)
          at com.ibm.ws.webcontainer.filter.WebAppFilterManager.doFilter(WebAppFilterManager.java:969)
          at com.ibm.ws.webcontainer.filter.WebAppFilterManager.invokeFilters(WebAppFilterManager.java:1109)
          at com.ibm.ws.webcontainer.servlet.CacheServletWrapper.handleRequest(CacheServletWrapper.java:82)
          at com.ibm.ws.webcontainer.WebContainer.handleRequest(WebContainer.java:963)
          at com.ibm.ws.webcontainer.WSWebContainer.handleRequest(WSWebContainer.java:1817)
          at com.ibm.ws.webcontainer.channel.WCChannelLink.ready(WCChannelLink.java:382)
          at com.ibm.ws.http.channel.inbound.impl.HttpInboundLink.handleDiscrimination(HttpInboundLink.java:465)
          at com.ibm.ws.http.channel.inbound.impl.HttpInboundLink.handleNewRequest(HttpInboundLink.java:532)
          at com.ibm.ws.http.channel.inbound.impl.HttpInboundLink.processRequest(HttpInboundLink.java:318)
          at com.ibm.ws.http.channel.inbound.impl.HttpInboundLink.ready(HttpInboundLink.java:289)
          at com.ibm.ws.ssl.channel.impl.SSLConnectionLink.determineNextChannel(Unknown Source)
          at com.ibm.ws.ssl.channel.impl.SSLConnectionLink.readyInboundPostHandshake(Unknown Source)
          at com.ibm.ws.ssl.channel.impl.SSLConnectionLink$MyHandshakeCompletedCallback.complete(Unknown Source)
          at com.ibm.ws.ssl.channel.impl.SSLUtils.handleHandshake(Unknown Source)
          at com.ibm.ws.ssl.channel.impl.SSLHandshakeIOCallback.complete(Unknown Source)
          at com.ibm.ws.tcp.channel.impl.AioReadCompletionListener.futureCompleted(Unknown Source)
          at com.ibm.io.async.AbstractAsyncFuture.invokeCallback(Unknown Source)
          at com.ibm.io.async.AsyncChannelFuture.fireCompletionActions(Unknown Source)
          at com.ibm.io.async.AsyncFuture.completed(Unknown Source)
          at com.ibm.io.async.ResultHandler.complete(Unknown Source)
          at com.ibm.io.async.ResultHandler.runEventProcessingLoop(Unknown Source)
          at com.ibm.io.async.ResultHandler$2.run(Unknown Source)
          at com.ibm.ws.util.ThreadPool$Worker.run(Unknown Source)
  Caused by: java.lang.IllegalArgumentException: UTILS-02001 Parameter 'filename' is null
          at org.camunda.commons.utils.EnsureUtilLogger.parameterIsNullException(EnsureUtilLogger.java:21)
          at org.camunda.commons.utils.EnsureUtil.ensureNotNull(EnsureUtil.java:31)
          at org.camunda.bpm.engine.variable.impl.value.builder.FileValueBuilderImpl.<init>(FileValueBuilderImpl.java:37)
          at org.camunda.bpm.engine.variable.Variables.fileValue(Variables.java:404)
          at org.camunda.bpm.engine.variable.Variables.fileValue(Variables.java:396)
          at org.camunda.bpm.engine.impl.variable.serializer.FileValueSerializer.readValue(FileValueSerializer.java:68)
          at org.camunda.bpm.engine.impl.variable.serializer.FileValueSerializer.readValue(FileValueSerializer.java:29)
          at org.camunda.bpm.engine.impl.persistence.entity.util.TypedValueField.getTypedValue(TypedValueField.java:93)
          at org.camunda.bpm.engine.impl.persistence.entity.util.TypedValueField.getTypedValue(TypedValueField.java:79)
          at org.camunda.bpm.engine.impl.persistence.entity.HistoricDetailVariableInstanceUpdateEntity.getTypedValue(HistoricDetailVariableInstanceUpdateEntity.java:49)
          at org.camunda.bpm.engine.rest.dto.history.HistoricVariableUpdateDto.fromHistoricVariableUpdate(HistoricVariableUpdateDto.java:80)
          at org.camunda.bpm.engine.rest.dto.history.HistoricOptimizeVariableUpdateDto.fromHistoricVariableUpdate(HistoricOptimizeVariableUpdateDto.java:32)
          at org.camunda.bpm.engine.rest.impl.optimize.OptimizeRestService.getHistoricVariableUpdates(OptimizeRestService.java:134)
          at sun.reflect.GeneratedMethodAccessor198.invoke(Unknown Source)
          at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
          at java.lang.reflect.Method.invoke(Unknown Source)
          at com.ibm.ws.jaxrs20.server.LibertyJaxRsServerFactoryBean.performInvocation(LibertyJaxRsServerFactoryBean.java:657)
          at com.ibm.ws.jaxrs20.server.LibertyJaxRsInvoker.performInvocation(LibertyJaxRsInvoker.java:108)
          at org.apache.cxf.service.invoker.AbstractInvoker.invoke(AbstractInvoker.java:97)
          ... 54 more