2.20.* -DallowMajorUpdates=false has bug

[HelloDhero]

when use version 2.20.* and -DallowMajorUpdates=false and config ignoreVersion by rule in maven-version-rules.xml i get the fllow exception

Caused by: java.lang.NullPointerException: Cannot invoke "org.apache.maven.artifact.versioning.ArtifactVersion.toString()" because "artifactVersion" is null
    at org.codehaus.mojo.versions.ordering.BoundArtifactVersion.<init> (BoundArtifactVersion.java:82)
    at org.codehaus.mojo.versions.api.AbstractVersionDetails.lambda$restrictionForUnchangedSegment$0 (AbstractVersionDetails.java:161)
    at java.util.Optional.map (Optional.java:260)
    at org.codehaus.mojo.versions.api.AbstractVersionDetails.restrictionForUnchangedSegment (AbstractVersionDetails.java:160)
    at org.codehaus.mojo.versions.internal.DependencyUpdatesLoggingHelper.getDependencyUpdates (DependencyUpdatesLoggingHelper.java:133)
    at org.codehaus.mojo.versions.DisplayDependencyUpdatesMojo.logUpdates (DisplayDependencyUpdatesMojo.java:555)
    at org.codehaus.mojo.versions.DisplayDependencyUpdatesMojo.execute (DisplayDependencyUpdatesMojo.java:478)
    at org.apache.maven.plugin.DefaultBuildPluginManager.executeMojo (DefaultBuildPluginManager.java:126)

[andrzejj0]

Are you able to share a minimal pom.xml that triggers this issue?

The reason why I'm asking this is that I suspect that you're using a dependency expressed as a version range and due to ignoredVersions, there are actually no versions being selected.

-DallowMajorUpdates=false activates a path in the code that leads to this NPE (which I'll fix in a tiny PR here), but I see that it is present in versions prior to 2.20.x.

Did it work for you with previous versions of the plugin? What was the output?

Ideally, a dependency causing a problem or a whole minimal pom.xml would be very helpful please.