I'm using xshell plugin on my Jenkins server for a while, so the configuration is old. When upgrade xshell to the latest version, the job will run into NPE, like this:

08:55:38 FATAL: null
08:55:38 java.lang.NullPointerException
08:55:38 at java.util.regex.Pattern.<init>(Pattern.java:1336)
08:55:38 at java.util.regex.Pattern.compile(Pattern.java:1022)
08:55:38 at hudson.plugins.xshell.XShellBuilder.perform(XShellBuilder.java:122)
08:55:38 at hudson.tasks.BuildStepMonitor$1.perform(BuildStepMonitor.java:20)
08:55:38 at hudson.model.AbstractBuild$AbstractBuildExecution.perform(AbstractBuild.java:785)
08:55:38 at hudson.model.Build$BuildExecution.build(Build.java:199)
08:55:38 at hudson.model.Build$BuildExecution.doRun(Build.java:160)
08:55:38 at hudson.model.AbstractBuild$AbstractBuildExecution.run(AbstractBuild.java:566)
08:55:38 at hudson.model.Run.execute(Run.java:1677)
08:55:38 at hudson.model.FreeStyleBuild.run(FreeStyleBuild.java:46)
08:55:38 at hudson.model.ResourceController.execute(ResourceController.java:88)
08:55:38 at hudson.model.Executor.run(Executor.java:230)

I guess this is caused by the missing xml tag "regexToKill" in old configuration files, the plugin should handle the old configurations more gracefully, but not throwing NEP.