NullPointerException on /ghprbhook

[eemmzz]

So I have just followed the instructions in the README and I have also tested the credentials in the 'manage Jenkins' section and all actions can be performed successfully.

When I go to: https://{jenkins-domain}/ghprbhook/ I get the following stack trace:

javax.servlet.ServletException: java.lang.NullPointerException
    at org.kohsuke.stapler.Stapler.tryInvoke(Stapler.java:796)
    at org.kohsuke.stapler.Stapler.invoke(Stapler.java:876)
    at org.kohsuke.stapler.MetaClass$13.dispatch(MetaClass.java:411)
    at org.kohsuke.stapler.Stapler.tryInvoke(Stapler.java:746)
    at org.kohsuke.stapler.Stapler.invoke(Stapler.java:876)
    at org.kohsuke.stapler.Stapler.invoke(Stapler.java:649)
    at org.kohsuke.stapler.Stapler.service(Stapler.java:238)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:848)
    at org.eclipse.jetty.servlet.ServletHolder.handle(ServletHolder.java:686)
    at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1494)
    at hudson.util.PluginServletFilter$1.doFilter(PluginServletFilter.java:132)
    at hudson.util.PluginServletFilter.doFilter(PluginServletFilter.java:123)
    at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1482)
    at hudson.security.csrf.CrumbFilter.doFilter(CrumbFilter.java:49)
    at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1482)
    at org.jenkinsci.plugins.reverse_proxy_auth.ReverseProxySecurityRealm$1.doFilter(ReverseProxySecurityRealm.java:468)
    at hudson.security.HudsonFilter.doFilter(HudsonFilter.java:171)
    at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1482)
    at org.kohsuke.stapler.compression.CompressionFilter.doFilter(CompressionFilter.java:49)
    at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1482)
    at hudson.util.CharacterEncodingFilter.doFilter(CharacterEncodingFilter.java:81)
    at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1482)
    at org.kohsuke.stapler.DiagnosticThreadNameFilter.doFilter(DiagnosticThreadNameFilter.java:30)
    at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1474)
    at org.eclipse.jetty.servlet.ServletHandler.doHandle(ServletHandler.java:499)
    at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:137)
    at org.eclipse.jetty.security.SecurityHandler.handle(SecurityHandler.java:533)
    at org.eclipse.jetty.server.session.SessionHandler.doHandle(SessionHandler.java:231)
    at org.eclipse.jetty.server.handler.ContextHandler.doHandle(ContextHandler.java:1086)
    at org.eclipse.jetty.servlet.ServletHandler.doScope(ServletHandler.java:428)
    at org.eclipse.jetty.server.session.SessionHandler.doScope(SessionHandler.java:193)
    at org.eclipse.jetty.server.handler.ContextHandler.doScope(ContextHandler.java:1020)
    at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:135)
    at org.eclipse.jetty.server.handler.HandlerWrapper.handle(HandlerWrapper.java:116)
    at org.eclipse.jetty.server.Server.handle(Server.java:370)
    at org.eclipse.jetty.server.AbstractHttpConnection.handleRequest(AbstractHttpConnection.java:489)
    at org.eclipse.jetty.server.AbstractHttpConnection.headerComplete(AbstractHttpConnection.java:949)
    at org.eclipse.jetty.server.AbstractHttpConnection$RequestHandler.headerComplete(AbstractHttpConnection.java:1011)
    at org.eclipse.jetty.http.HttpParser.parseNext(HttpParser.java:644)
    at org.eclipse.jetty.http.HttpParser.parseAvailable(HttpParser.java:235)
    at org.eclipse.jetty.server.AsyncHttpConnection.handle(AsyncHttpConnection.java:82)
    at org.eclipse.jetty.io.nio.SelectChannelEndPoint.handle(SelectChannelEndPoint.java:668)
    at org.eclipse.jetty.io.nio.SelectChannelEndPoint$1.run(SelectChannelEndPoint.java:52)
    at winstone.BoundedExecutorService$1.run(BoundedExecutorService.java:77)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
    at java.lang.Thread.run(Thread.java:745)
Caused by: java.lang.NullPointerException
    at org.jenkinsci.plugins.ghprb.GhprbRootAction.doIndex(GhprbRootAction.java:79)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:606)
    at org.kohsuke.stapler.Function$InstanceFunction.invoke(Function.java:298)
    at org.kohsuke.stapler.Function.bindAndInvoke(Function.java:161)
    at org.kohsuke.stapler.Function.bindAndInvokeAndServeResponse(Function.java:96)
    at org.kohsuke.stapler.MetaClass$2.dispatch(MetaClass.java:165)
    at org.kohsuke.stapler.Stapler.tryInvoke(Stapler.java:746)
    ... 46 more

I've tried the Jenkins log file for any extra information and there isn't any that I can see.

We're using: github api 1.72.1, github 1.18.2, github pull request builder 1.31.4, matrix project 1.6, git 2.4.4, plain credentials 1.1, credentials 1.27, ssh-agent 1.10

Anyone able to help out? We only have one job setup to trigger with the pull request builder so it shouldn't be anything like inactive projects as I've seen when searching through previous issues.

[DavidTanner]

That isnt really a url that you navigate to, which version of the plugin are you using?

[eemmzz]

I understand that it isn't really an endpoint to navigate to but I assumed the stack trace was an indication of something going wrong (I could be wrong on that). The other symptom we're getting is on the GitHub side we get a response: 0 when the webhook is fired. All the versions are listed above and we're using v1.31.4

[DavidTanner]

Set a content-type on your request and see if it still throws an exception