In BlueOcean we have Multi branch pipeline tests that fail randomly, hard to reproduce. Tests do the following steps:

• Create local git repo with Jennkisfile with simple pipeline, create multiple branches. See MultiBranchPipelineTest.setupScm()
• Use JenkinsRule to call API that returns DAG built using FlowGraphWalker

NPE randomly occurs at PipelineStepImpl.java:27

Line 27 in PipelineStepImpl can't give NPE. So either the stack trace is incorrectly reported and NPE is somewhere else. Since its so random that we are not able to debug. Any insight is appreciated. I have copied workflow-plugin as well as multi-branch-project-plugin, I don't know if there is bug there in these plugins as stack trace is not saying everything but maybe it has something happens during groovy DSL processing or some other file system race condition.

Here is the complete stack trace reported by Unit. kohsuke Its the same issue I discussed the other day where tests random fail executing pipeline multi branch job.

java.lang.NullPointerException
at io.jenkins.blueocean.service.embedded.rest.PipelineStepImpl.<init>(PipelineStepImpl.java:27)
at io.jenkins.blueocean.service.embedded.rest.PipelineStepContainerImpl.iterator(PipelineStepContainerImpl.java:51)
at org.kohsuke.stapler.export.Range$1.iterator(Range.java:44)
at org.kohsuke.stapler.export.Property.writeValue(Property.java:221)
at org.kohsuke.stapler.export.Property.writeValue(Property.java:168)
at org.kohsuke.stapler.export.Property.writeTo(Property.java:139)
at org.kohsuke.stapler.export.Model.writeNestedObjectTo(Model.java:227)
at org.kohsuke.stapler.export.Model.writeNestedObjectTo(Model.java:223)
at org.kohsuke.stapler.export.Model.writeNestedObjectTo(Model.java:223)
at org.kohsuke.stapler.export.Property.writeValue(Property.java:279)
at org.kohsuke.stapler.export.Property.writeValue(Property.java:168)
at org.kohsuke.stapler.export.Property.writeTo(Property.java:139)
at org.kohsuke.stapler.export.Model.writeNestedObjectTo(Model.java:227)
at org.kohsuke.stapler.export.Model.writeNestedObjectTo(Model.java:223)
at org.kohsuke.stapler.export.Model.writeNestedObjectTo(Model.java:223)
at org.kohsuke.stapler.export.Model.writeTo(Model.java:198)
at org.kohsuke.stapler.ResponseImpl.writeOne(ResponseImpl.java:285)
at org.kohsuke.stapler.ResponseImpl.serveExposedBean(ResponseImpl.java:273)
at hudson.model.Api.doJson(Api.java:211)
at io.jenkins.blueocean.rest.pageable.PagedResponse$Processor$1.generateResponse(PagedResponse.java:55)
at org.kohsuke.stapler.HttpResponseRenderer$Default.handleHttpResponse(HttpResponseRenderer.java:124)
at org.kohsuke.stapler.HttpResponseRenderer$Default.generateResponse(HttpResponseRenderer.java:69)
at org.kohsuke.stapler.Function.renderResponse(Function.java:119)
at org.kohsuke.stapler.Function.bindAndInvokeAndServeResponse(Function.java:102)
at org.kohsuke.stapler.IndexDispatcher.dispatch(IndexDispatcher.java:26)
at org.kohsuke.stapler.Stapler.tryInvoke(Stapler.java:746)
at org.kohsuke.stapler.Stapler.invoke(Stapler.java:876)
at org.kohsuke.stapler.MetaClass$3.doDispatch(MetaClass.java:196)
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.MetaClass$11.dispatch(MetaClass.java:380)
at org.kohsuke.stapler.Stapler.tryInvoke(Stapler.java:746)
at org.kohsuke.stapler.Stapler.invoke(Stapler.java:876)
at org.kohsuke.stapler.MetaClass$3.doDispatch(MetaClass.java:196)
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.MetaClass$11.dispatch(MetaClass.java:380)
at org.kohsuke.stapler.Stapler.tryInvoke(Stapler.java:746)
at org.kohsuke.stapler.Stapler.invoke(Stapler.java:876)
at org.kohsuke.stapler.MetaClass$11.dispatch(MetaClass.java:380)
at org.kohsuke.stapler.Stapler.tryInvoke(Stapler.java:746)
at org.kohsuke.stapler.Stapler.invoke(Stapler.java:876)
at org.kohsuke.stapler.MetaClass$11.dispatch(MetaClass.java:380)
at org.kohsuke.stapler.Stapler.tryInvoke(Stapler.java:746)
at org.kohsuke.stapler.Stapler.invoke(Stapler.java:876)
at org.kohsuke.stapler.Stapler.tryInvoke(Stapler.java:686)
at org.kohsuke.stapler.Stapler.invoke(Stapler.java:876)
at org.kohsuke.stapler.MetaClass$11.dispatch(MetaClass.java:380)
at org.kohsuke.stapler.Stapler.tryInvoke(Stapler.java:746)
at org.kohsuke.stapler.Stapler.invoke(Stapler.java:876)
at org.kohsuke.stapler.Stapler.invoke(Stapler.java:649)
at org.kohsuke.stapler.Stapler.service(Stapler.java:238)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:790)
at org.eclipse.jetty.servlet.ServletHolder.handle(ServletHolder.java:812)
at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1669)
at hudson.util.PluginServletFilter$1.doFilter(PluginServletFilter.java:135)
at org.jenkinsci.plugins.ssegateway.Endpoint$SSEListenChannelFilter.doFilter(Endpoint.java:209)
at hudson.util.PluginServletFilter$1.doFilter(PluginServletFilter.java:132)
at jenkins.metrics.impl.MetricsFilter.doFilter(MetricsFilter.java:117)
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:86)
at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1652)
at hudson.security.ChainedServletFilter$1.doFilter(ChainedServletFilter.java:84)
at hudson.security.ChainedServletFilter.doFilter(ChainedServletFilter.java:76)
at hudson.security.HudsonFilter.doFilter(HudsonFilter.java:171)
at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1652)
at org.kohsuke.stapler.compression.CompressionFilter.doFilter(CompressionFilter.java:49)
at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1652)
at hudson.util.CharacterEncodingFilter.doFilter(CharacterEncodingFilter.java:81)
at org.eclipse.jetty.servlet.ServletHandler$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$2.run(AbstractConnection.java:544)
at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511)
at java.util.concurrent.FutureTask.run(FutureTask.java:266)
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)