Unable to run mvn incrementals command

[ravin-accelq]

Service(s)

Incrementals

Summary

Hi,I'm not able to run mvn incrementals command, here is the link to POM file: https://github.com/jenkinsci/accelq-ci-connect-plugin/blob/main/pom.xml

Error message: Failed to execute goal io.jenkins.tools.incrementals:incrementals-maven-plugin:1.2:incrementalify (default-cli) on project accelq-ci-connect: Execution default-cli of goal io.jenkins.tools.incrementals:incrementals-maven-plugin:1.2:incrementalify failed.: NullPointerException -> [Help 1]

Reproduction steps

No response

[dduportal]

cc @olamy for info as you might be suffering from the same issue (or not?).

The infra team is looking into this, thanks for reporting!

[dduportal]

Hi @accelq , just to be sure: did you follow each step described in https://www.jenkins.io/doc/developer/tutorial-improve/enable-incrementals/ ?

If yes, can you share the commands you type (so we could try reproducing your error)?

[MarkEWaite]

@accelq I see the same null pointer exception when I try to run mvn incrementals:incrementalify on your repository. That likely indicates a bug in the incrementals plugin for maven. That's not an infrastructure issue. I recommend closing this infrastructure issue or moving it to the incrementals tools repository.

However, your repository is attempting to support Jenkins versions as old as Jenkins 2.222.3 and is using Java 8. The Jenkins project dropped support for Java 8 a year ago. The Jenkins project provides security fixes for the most recent LTS (currently 2.401.3) and the most recent weekly (currently 2.418). Both those versions require Java 11 and support Java 17. Jenkins tooling generally requires Java 11 and a minimum Jenkins version of 2.361.4.

I will be surprised if you're able to use the current Jenkins tooling (like incrementals) with a plugin that is trying to support Java 8 and Jenkins versions that are many years out of date. It may work, but you're much more likely to succeed if you modernize your plugin first, then attempt to use modern features like incrementals and continuous delivery. If you want to take the modernization even further, you can see more suggestions in the Contributing to Open Source google doc.

[ravin-accelq]

hi, I've updated the plugin, using the modernize steps. I've raised ticket in incrementals repo jenkinsci/incrementals-tools#73

Still seeing the same issue, will wait for their reply

[dduportal]

I've tried and I can reproduce the error with a JDK11 on my laptop.

If I switch to a JDK 17, I got the following error:

[ERROR] Failed to execute goal io.jenkins.tools.incrementals:incrementals-maven-plugin:1.7:incrementalify (default-cli) on project accelq-ci-connect: Execution default-cli of goal io.jenkins.tools.incrementals:incrementals-maven-plugin:1.7:incrementalify failed: Cannot invoke "java.lang.CharSequence.length()" because "this.text" is null -> [Help 1]

[timja]

ah there's an old bug in maven-compiler-plugin that just gives a nullpointer in certain edge cases.
you get the proper error on Java 17 like you found

[dduportal]

Hello @accelq you got a PR: jenkinsci/accelq-ci-connect-plugin#17 to fix this issue.

It feels like the documentation at https://www.jenkins.io/doc/developer/tutorial-improve/enable-incrementals/ could be updated to provides the requirements, would you be willing to add it (I would but I'm alone maintaining the Jenkins infra this week so any help is welcome)

[ravin-accelq]

Thanks