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[JENKINS-42658] computer.getOSDescription() throws NPE if slave is off-line #21927

Description

@jenkins-infra-bot

We have the following code:

Hudson.instance.slaves.collect { slave ->
    def isOnline = slave.computer.isOnline()
    [
      name: slave.getNodeName(),
      description: slave.getNodeDescription(),
      isUnix: slave.computer.isUnix(),
      // os: slave.computer.getOSDescription(),
      // getOSDescription() throws NPE if slave is off line.
      os: isOnline ? slave.computer.getOSDescription() : null,
      remoteHomeDir: slave.getRemoteFS(),
      labels: slave.getAssignedLabels().collect { l -> l.toString() },
      isOnline: isOnline
    ] as Map
  }

This seems amiss since isUnix() does not throw an NPE but returns null in this case. It seems they should both behave in the same way. And if the decision is that they should both throw, the an meaningful error about the slave being off-line would be appropriate.

Note this may not happen every time a slave is off line. I did not test this but I suspect It may only happen if the slave has never been online since its creation or possibly since the master last started.

Steps to reproduce are as follows:

1. Create a new slave given only a name and left off line.
2. Run the above code in the script console with the unguarded `// os: slave.computer.getOSDescription(),` line uncommented.

Result:

java.lang.NullPointerException
	at hudson.slaves.SlaveComputer.getOSDescription(SlaveComputer.java:762)
	at hudson.slaves.SlaveComputer$getOSDescription.call(Unknown Source)
	at Script1$_run_closure1.doCall(Script1.groovy:7)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.lang.reflect.Method.invoke(Method.java:498)
	at org.codehaus.groovy.reflection.CachedMethod.invoke(CachedMethod.java:93)
	at groovy.lang.MetaMethod.doMethodInvoke(MetaMethod.java:325)
	at org.codehaus.groovy.runtime.metaclass.ClosureMetaClass.invokeMethod(ClosureMetaClass.java:294)
	at groovy.lang.MetaClassImpl.invokeMethod(MetaClassImpl.java:1024)
	at groovy.lang.Closure.call(Closure.java:414)
	at groovy.lang.Closure.call(Closure.java:430)
	at org.codehaus.groovy.runtime.DefaultGroovyMethods.collect(DefaultGroovyMethods.java:3170)
	at org.codehaus.groovy.runtime.DefaultGroovyMethods.collect(DefaultGroovyMethods.java:3140)
	at org.codehaus.groovy.runtime.dgm$66.invoke(Unknown Source)
	at org.codehaus.groovy.runtime.callsite.PojoMetaMethodSite$PojoMetaMethodSiteNoUnwrapNoCoerce.invoke(PojoMetaMethodSite.java:274)
	at org.codehaus.groovy.runtime.callsite.PojoMetaMethodSite.call(PojoMetaMethodSite.java:56)
	at org.codehaus.groovy.runtime.callsite.CallSiteArray.defaultCall(CallSiteArray.java:48)
	at org.codehaus.groovy.runtime.callsite.AbstractCallSite.call(AbstractCallSite.java:113)
	at org.codehaus.groovy.runtime.callsite.AbstractCallSite.call(AbstractCallSite.java:125)
	at Script1.run(Script1.groovy:1)
	at groovy.lang.GroovyShell.evaluate(GroovyShell.java:585)
	at groovy.lang.GroovyShell.evaluate(GroovyShell.java:623)
	at groovy.lang.GroovyShell.evaluate(GroovyShell.java:594)
	at hudson.util.RemotingDiagnostics$Script.call(RemotingDiagnostics.java:142)
	at hudson.util.RemotingDiagnostics$Script.call(RemotingDiagnostics.java:114)
	at hudson.remoting.LocalChannel.call(LocalChannel.java:45)
	at hudson.util.RemotingDiagnostics.executeGroovy(RemotingDiagnostics.java:111)
	at jenkins.model.Jenkins._doScript(Jenkins.java:4191)
	at jenkins.model.Jenkins.doScript(Jenkins.java:4163)
	at sun.reflect.GeneratedMethodAccessor5352.invoke(Unknown Source)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.lang.reflect.Method.invoke(Method.java:498)
	at org.kohsuke.stapler.Function$InstanceFunction.invoke(Function.java:324)
	at org.kohsuke.stapler.Function.bindAndInvoke(Function.java:167)
	at org.kohsuke.stapler.Function.bindAndInvokeAndServeResponse(Function.java:100)
	at org.kohsuke.stapler.MetaClass$1.doDispatch(MetaClass.java:124)
	at org.kohsuke.stapler.NameBasedDispatcher.dispatch(NameBasedDispatcher.java:58)
	at org.kohsuke.stapler.Stapler.tryInvoke(Stapler.java:746)
	at org.kohsuke.stapler.Stapler.invoke(Stapler.java:876)
	at org.kohsuke.stapler.Stapler.invoke(Stapler.java:649)
	at org.kohsuke.stapler.Stapler.service(Stapler.java:238)
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:790)
	at org.eclipse.jetty.servlet.ServletHolder.handle(ServletHolder.java:812)
	at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1669)
	at hudson.util.PluginServletFilter$1.doFilter(PluginServletFilter.java:135)
	at com.cloudbees.jenkins.support.slowrequest.SlowRequestFilter.doFilter(SlowRequestFilter.java:38)
	at hudson.util.PluginServletFilter$1.doFilter(PluginServletFilter.java:132)
	at hudson.plugins.audit_trail.AuditTrailFilter.doFilter(AuditTrailFilter.java:95)
	at hudson.util.PluginServletFilter$1.doFilter(PluginServletFilter.java:132)
	at jenkins.metrics.impl.MetricsFilter.doFilter(MetricsFilter.java:125)
	at hudson.util.PluginServletFilter$1.doFilter(PluginServletFilter.java:132)
	at hudson.util.PluginServletFilter.doFilter(PluginServletFilter.java:126)
	at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1652)
	at hudson.security.csrf.CrumbFilter.doFilter(CrumbFilter.java:49)
	at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1652)
	at hudson.security.ChainedServletFilter$1.doFilter(ChainedServletFilter.java:84)
	at hudson.security.UnwrapSecurityExceptionFilter.doFilter(UnwrapSecurityExceptionFilter.java:51)
	at hudson.security.ChainedServletFilter$1.doFilter(ChainedServletFilter.java:87)
	at jenkins.security.ExceptionTranslationFilter.doFilter(ExceptionTranslationFilter.java:117)
	at hudson.security.ChainedServletFilter$1.doFilter(ChainedServletFilter.java:87)
	at org.acegisecurity.providers.anonymous.AnonymousProcessingFilter.doFilter(AnonymousProcessingFilter.java:125)
	at hudson.security.ChainedServletFilter$1.doFilter(ChainedServletFilter.java:87)
	at org.acegisecurity.ui.rememberme.RememberMeProcessingFilter.doFilter(RememberMeProcessingFilter.java:142)
	at hudson.security.ChainedServletFilter$1.doFilter(ChainedServletFilter.java:87)
	at org.acegisecurity.ui.AbstractProcessingFilter.doFilter(AbstractProcessingFilter.java:271)
	at hudson.security.ChainedServletFilter$1.doFilter(ChainedServletFilter.java:87)
	at jenkins.security.BasicHeaderProcessor.doFilter(BasicHeaderProcessor.java:93)
	at hudson.security.ChainedServletFilter$1.doFilter(ChainedServletFilter.java:87)
	at org.acegisecurity.context.HttpSessionContextIntegrationFilter.doFilter(HttpSessionContextIntegrationFilter.java:249)
	at hudson.security.HttpSessionContextIntegrationFilter2.doFilter(HttpSessionContextIntegrationFilter2.java:67)
	at hudson.security.ChainedServletFilter$1.doFilter(ChainedServletFilter.java:87)
	at hudson.security.ChainedServletFilter.doFilter(ChainedServletFilter.java:76)
	at hudson.security.HudsonFilter.doFilter(HudsonFilter.java:171)
	at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1652)
	at org.kohsuke.stapler.compression.CompressionFilter.doFilter(CompressionFilter.java:49)
	at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1652)
	at hudson.util.CharacterEncodingFilter.doFilter(CharacterEncodingFilter.java:82)
	at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1652)
	at org.kohsuke.stapler.DiagnosticThreadNameFilter.doFilter(DiagnosticThreadNameFilter.java:30)
	at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1652)
	at org.eclipse.jetty.servlet.ServletHandler.doHandle(ServletHandler.java:585)
	at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:143)
	at org.eclipse.jetty.security.SecurityHandler.handle(SecurityHandler.java:553)
	at org.eclipse.jetty.server.session.SessionHandler.doHandle(SessionHandler.java:223)
	at org.eclipse.jetty.server.handler.ContextHandler.doHandle(ContextHandler.java:1127)
	at org.eclipse.jetty.servlet.ServletHandler.doScope(ServletHandler.java:515)
	at org.eclipse.jetty.server.session.SessionHandler.doScope(SessionHandler.java:185)
	at org.eclipse.jetty.server.handler.ContextHandler.doScope(ContextHandler.java:1061)
	at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:141)
	at org.eclipse.jetty.server.handler.HandlerWrapper.handle(HandlerWrapper.java:97)
	at org.eclipse.jetty.server.Server.handle(Server.java:499)
	at org.eclipse.jetty.server.HttpChannel.handle(HttpChannel.java:311)
	at org.eclipse.jetty.server.HttpConnection.onFillable(HttpConnection.java:257)
	at org.eclipse.jetty.io.AbstractConnection$2.run(AbstractConnection.java:544)
	at winstone.BoundedExecutorService$1.run(BoundedExecutorService.java:77)
	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
	at java.lang.Thread.run(Thread.java:745)

Originally reported by kbaltrinic, imported from: computer.getOSDescription() throws NPE if slave is off-line
  • assignee: oleg_nenashev
  • status: Resolved
  • priority: Minor
  • component(s): core
  • label(s): 2.204.3-fixed, newbie-friendly
  • resolution: Fixed
  • resolved: 2020-01-15T12:10:09+00:00
  • votes: 0
  • watchers: 4
  • imported: 2025-11-24
Raw content of original issue

We have the following code:

Hudson.instance.slaves.collect { slave ->
    def isOnline = slave.computer.isOnline()
    [
      name: slave.getNodeName(),
      description: slave.getNodeDescription(),
      isUnix: slave.computer.isUnix(),
      // os: slave.computer.getOSDescription(),
      // getOSDescription() throws NPE if slave is off line.
      os: isOnline ? slave.computer.getOSDescription() : null,
      remoteHomeDir: slave.getRemoteFS(),
      labels: slave.getAssignedLabels().collect { l -> l.toString() },
      isOnline: isOnline
    ] as Map
  }

This seems amiss since isUnix() does not throw an NPE but returns null in this case. It seems they should both behave in the same way. And if the decision is that they should both throw, the an meaningful error about the slave being off-line would be appropriate.

Note this may not happen every time a slave is off line. I did not test this but I suspect It may only happen if the slave has never been online since its creation or possibly since the master last started.

Steps to reproduce are as follows:

1. Create a new slave given only a name and left off line. 2. Run the above code in the script console with the unguarded `// os: slave.computer.getOSDescription(),` line uncommented.

Result:

java.lang.NullPointerException
	at hudson.slaves.SlaveComputer.getOSDescription(SlaveComputer.java:762)
	at hudson.slaves.SlaveComputer$getOSDescription.call(Unknown Source)
	at Script1$_run_closure1.doCall(Script1.groovy:7)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.lang.reflect.Method.invoke(Method.java:498)
	at org.codehaus.groovy.reflection.CachedMethod.invoke(CachedMethod.java:93)
	at groovy.lang.MetaMethod.doMethodInvoke(MetaMethod.java:325)
	at org.codehaus.groovy.runtime.metaclass.ClosureMetaClass.invokeMethod(ClosureMetaClass.java:294)
	at groovy.lang.MetaClassImpl.invokeMethod(MetaClassImpl.java:1024)
	at groovy.lang.Closure.call(Closure.java:414)
	at groovy.lang.Closure.call(Closure.java:430)
	at org.codehaus.groovy.runtime.DefaultGroovyMethods.collect(DefaultGroovyMethods.java:3170)
	at org.codehaus.groovy.runtime.DefaultGroovyMethods.collect(DefaultGroovyMethods.java:3140)
	at org.codehaus.groovy.runtime.dgm$66.invoke(Unknown Source)
	at org.codehaus.groovy.runtime.callsite.PojoMetaMethodSite$PojoMetaMethodSiteNoUnwrapNoCoerce.invoke(PojoMetaMethodSite.java:274)
	at org.codehaus.groovy.runtime.callsite.PojoMetaMethodSite.call(PojoMetaMethodSite.java:56)
	at org.codehaus.groovy.runtime.callsite.CallSiteArray.defaultCall(CallSiteArray.java:48)
	at org.codehaus.groovy.runtime.callsite.AbstractCallSite.call(AbstractCallSite.java:113)
	at org.codehaus.groovy.runtime.callsite.AbstractCallSite.call(AbstractCallSite.java:125)
	at Script1.run(Script1.groovy:1)
	at groovy.lang.GroovyShell.evaluate(GroovyShell.java:585)
	at groovy.lang.GroovyShell.evaluate(GroovyShell.java:623)
	at groovy.lang.GroovyShell.evaluate(GroovyShell.java:594)
	at hudson.util.RemotingDiagnostics$Script.call(RemotingDiagnostics.java:142)
	at hudson.util.RemotingDiagnostics$Script.call(RemotingDiagnostics.java:114)
	at hudson.remoting.LocalChannel.call(LocalChannel.java:45)
	at hudson.util.RemotingDiagnostics.executeGroovy(RemotingDiagnostics.java:111)
	at jenkins.model.Jenkins._doScript(Jenkins.java:4191)
	at jenkins.model.Jenkins.doScript(Jenkins.java:4163)
	at sun.reflect.GeneratedMethodAccessor5352.invoke(Unknown Source)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.lang.reflect.Method.invoke(Method.java:498)
	at org.kohsuke.stapler.Function$InstanceFunction.invoke(Function.java:324)
	at org.kohsuke.stapler.Function.bindAndInvoke(Function.java:167)
	at org.kohsuke.stapler.Function.bindAndInvokeAndServeResponse(Function.java:100)
	at org.kohsuke.stapler.MetaClass$1.doDispatch(MetaClass.java:124)
	at org.kohsuke.stapler.NameBasedDispatcher.dispatch(NameBasedDispatcher.java:58)
	at org.kohsuke.stapler.Stapler.tryInvoke(Stapler.java:746)
	at org.kohsuke.stapler.Stapler.invoke(Stapler.java:876)
	at org.kohsuke.stapler.Stapler.invoke(Stapler.java:649)
	at org.kohsuke.stapler.Stapler.service(Stapler.java:238)
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:790)
	at org.eclipse.jetty.servlet.ServletHolder.handle(ServletHolder.java:812)
	at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1669)
	at hudson.util.PluginServletFilter$1.doFilter(PluginServletFilter.java:135)
	at com.cloudbees.jenkins.support.slowrequest.SlowRequestFilter.doFilter(SlowRequestFilter.java:38)
	at hudson.util.PluginServletFilter$1.doFilter(PluginServletFilter.java:132)
	at hudson.plugins.audit_trail.AuditTrailFilter.doFilter(AuditTrailFilter.java:95)
	at hudson.util.PluginServletFilter$1.doFilter(PluginServletFilter.java:132)
	at jenkins.metrics.impl.MetricsFilter.doFilter(MetricsFilter.java:125)
	at hudson.util.PluginServletFilter$1.doFilter(PluginServletFilter.java:132)
	at hudson.util.PluginServletFilter.doFilter(PluginServletFilter.java:126)
	at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1652)
	at hudson.security.csrf.CrumbFilter.doFilter(CrumbFilter.java:49)
	at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1652)
	at hudson.security.ChainedServletFilter$1.doFilter(ChainedServletFilter.java:84)
	at hudson.security.UnwrapSecurityExceptionFilter.doFilter(UnwrapSecurityExceptionFilter.java:51)
	at hudson.security.ChainedServletFilter$1.doFilter(ChainedServletFilter.java:87)
	at jenkins.security.ExceptionTranslationFilter.doFilter(ExceptionTranslationFilter.java:117)
	at hudson.security.ChainedServletFilter$1.doFilter(ChainedServletFilter.java:87)
	at org.acegisecurity.providers.anonymous.AnonymousProcessingFilter.doFilter(AnonymousProcessingFilter.java:125)
	at hudson.security.ChainedServletFilter$1.doFilter(ChainedServletFilter.java:87)
	at org.acegisecurity.ui.rememberme.RememberMeProcessingFilter.doFilter(RememberMeProcessingFilter.java:142)
	at hudson.security.ChainedServletFilter$1.doFilter(ChainedServletFilter.java:87)
	at org.acegisecurity.ui.AbstractProcessingFilter.doFilter(AbstractProcessingFilter.java:271)
	at hudson.security.ChainedServletFilter$1.doFilter(ChainedServletFilter.java:87)
	at jenkins.security.BasicHeaderProcessor.doFilter(BasicHeaderProcessor.java:93)
	at hudson.security.ChainedServletFilter$1.doFilter(ChainedServletFilter.java:87)
	at org.acegisecurity.context.HttpSessionContextIntegrationFilter.doFilter(HttpSessionContextIntegrationFilter.java:249)
	at hudson.security.HttpSessionContextIntegrationFilter2.doFilter(HttpSessionContextIntegrationFilter2.java:67)
	at hudson.security.ChainedServletFilter$1.doFilter(ChainedServletFilter.java:87)
	at hudson.security.ChainedServletFilter.doFilter(ChainedServletFilter.java:76)
	at hudson.security.HudsonFilter.doFilter(HudsonFilter.java:171)
	at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1652)
	at org.kohsuke.stapler.compression.CompressionFilter.doFilter(CompressionFilter.java:49)
	at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1652)
	at hudson.util.CharacterEncodingFilter.doFilter(CharacterEncodingFilter.java:82)
	at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1652)
	at org.kohsuke.stapler.DiagnosticThreadNameFilter.doFilter(DiagnosticThreadNameFilter.java:30)
	at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1652)
	at org.eclipse.jetty.servlet.ServletHandler.doHandle(ServletHandler.java:585)
	at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:143)
	at org.eclipse.jetty.security.SecurityHandler.handle(SecurityHandler.java:553)
	at org.eclipse.jetty.server.session.SessionHandler.doHandle(SessionHandler.java:223)
	at org.eclipse.jetty.server.handler.ContextHandler.doHandle(ContextHandler.java:1127)
	at org.eclipse.jetty.servlet.ServletHandler.doScope(ServletHandler.java:515)
	at org.eclipse.jetty.server.session.SessionHandler.doScope(SessionHandler.java:185)
	at org.eclipse.jetty.server.handler.ContextHandler.doScope(ContextHandler.java:1061)
	at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:141)
	at org.eclipse.jetty.server.handler.HandlerWrapper.handle(HandlerWrapper.java:97)
	at org.eclipse.jetty.server.Server.handle(Server.java:499)
	at org.eclipse.jetty.server.HttpChannel.handle(HttpChannel.java:311)
	at org.eclipse.jetty.server.HttpConnection.onFillable(HttpConnection.java:257)
	at org.eclipse.jetty.io.AbstractConnection$2.run(AbstractConnection.java:544)
	at winstone.BoundedExecutorService$1.run(BoundedExecutorService.java:77)
	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
	at java.lang.Thread.run(Thread.java:745)
  • environment: Jenkins 2.19.3

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