Rouke Broersma Could you please provide /extra/jenkins/selenium.xml from your instance?

I no longer run a Jenkins instance with this plugin so I cannot provide the file from my instance.

Rouke Broersma sorry, my intention was to ask Björn Pedersen who reported the issue

Rouke Broersma BTW, you are listed as a plugin lead in JIRA. Just in case we need a fix for this issue (needs to be confirmed first), would you be able to spin the release?

Just added the selenium.xml file

Oleg Nenashev I can spin a release yes. I am a bit rusty on plugin config stuff but I think any @Exported thing can cause this problem right? In the plugin sources I found the following exotic exports that were not simple string, int, bool values. A number of them I think will probably save as string anyway because of transitive Exports further down in the object (unless that does not happen by default, like I said, rusty) but maybe this list can help you narrow down if it's caused by JEP-200:

@Exported
public Map<String, String> getCapabilities() {
return capabilities;
}

@Exported
public List<SeleniumBrowser> getBrowsers() {
return browsers;
}

@Exported
public SeleniumConfigurationMatcher getMatcher() {
return matcher;
}

@Exported
public List<WebDriverBrowser> getBrowsers() {
return browsers;
}

@Exported
public HostnameResolver getHostnameResolver() {
return hostnameResolver;
}

@Exported( inline = true )
public Collection<SeleniumTestSlotGroup> getRemoteControls() throws IOException, InterruptedException {

@Exported
public List<SeleniumGlobalConfiguration> getGlobalConfigurations() {
return configurations;
}

OK, it seems that the plugin fails to convert a valid structure due to whatever reason

Caused: com.thoughtworks.xstream.converters.ConversionException: null : null ---- Debugging information ---- cause-exception : java.lang.NullPointerException cause-message : null class : hudson.plugins.selenium.PluginImpl required-type : hudson.plugins.selenium.PluginImpl converter-type : hudson.util.RobustReflectionConverter path : /hudson.plugins.selenium.PluginImpl line number : 31 version : not available ------------------------------- at

Whatever happens, it definitely looks like a bug in the Jenkins core.
It fails because Old Data Monitor is null at the timeframe of data migration.

I will try to reproduce it once I have progress on JENKINS-48983

Rouke Broersma thanks! It's unlikely (Exporting does not use whitelist) but I will keep it in mind

Björn Pedersen Would you be able to run a "return hudson.diagnosis.OldDataMonitor.get(jenkins.model.Jenkins.instance)" command in the System console? Just to exclude the obvious thing.

Cannot reproduce that issue with Selenium locally, but I will keep trying

Oleg Nenashev Keep in mind that according to the selenium config provided by Björn Pedersen they are running version 2.3 of the plugin which is really old. The latest plugin version might not actually have the issue so perhaps that's why you can't reproduce.

I have verified the issue on the latest version of the plugin.

• The provided config XML fails on 2.102
• It fails on 2.101 as well...

Whatever the root cause of this issue is, it is not a JEP-200 regression AFAICT. But I will triage it to make sure

Likely it is something in the core

There were some issues with config not being correctly converted to new plugin config versions in the past. Perhaps their config version is just not compatible with the new versions of the plugin (and the conversion is not working properly). Perhaps it's not a Jenkins problem at all, but simply the plugin having a bug.

Meanwhile I ran Plugin Compatibility Tester. With all current tests the plugin works well on Jenkins 2.102

Rouke Broersma Maybe we will have to split it to two issues. Old Data Monitor failing with NPE does seem like a core bug, independently of what causes that.
If you prefer, I can move it to a separate ticket.

The selenium bug does not really have priority as no users of the plugin should be on such an old version anyway. You can keep the ticket for the core bug and I will create my own.

"return hudson.diagnosis.OldDataMonitor.get(jenkins.model.Jenkins.instance)"

 =>

hudson.diagnosis.OldDataMonitor@b3fef1

An update: After all other plugins that had JEP-200 problems are fixed, this error is gone again.

OK, so let's consider that there is no new issues in the Selenium plugin itself.
I will handle this ticket on the core's side

I ran into the same issue when working on a change on gerrit-trigger plugin. My guess is that OldDataMonitor gets initialized after the plugin is loaded.

What I did was removing a field from a persisted class. After Jenkins gets restarted it tries to load the old config XML file (which contains the deleted field) and boom, it cannot report it because OldDataMonitor is null.

Diagnostics was improved in 2.163.

Petres Andras if you still experience the issue, it would be great to have updated stacktraces after the update