Interaction between ranges/scope provokes NullPointerException

[TobiX]

When running mvn site in the
attached test project, the following exception is thrown:

Exception

[ERROR] Failed to execute goal org.apache.maven.plugins:maven-site-plugin:3.12.1:site (default-site) on project parent: Error generating versions-maven-plugin:2.15.0:dependency-updates-aggregate-report report: NullPointerException -> [Help 1]
org.apache.maven.lifecycle.LifecycleExecutionException: Failed to execute goal org.apache.maven.plugins:maven-site-plugin:3.12.1:site (default-site) on project parent: Error generating versions-maven-plugin:2.15.0:dependency-updates-aggregate-report report
    at org.apache.maven.lifecycle.internal.MojoExecutor.doExecute2 (MojoExecutor.java:347)
    at org.apache.maven.lifecycle.internal.MojoExecutor.doExecute (MojoExecutor.java:330)
    at org.apache.maven.lifecycle.internal.MojoExecutor.execute (MojoExecutor.java:213)
    at org.apache.maven.lifecycle.internal.MojoExecutor.execute (MojoExecutor.java:175)
    at org.apache.maven.lifecycle.internal.MojoExecutor.access$000 (MojoExecutor.java:76)
    at org.apache.maven.lifecycle.internal.MojoExecutor$1.run (MojoExecutor.java:163)
    at org.apache.maven.plugin.DefaultMojosExecutionStrategy.execute (DefaultMojosExecutionStrategy.java:39)
    at org.apache.maven.lifecycle.internal.MojoExecutor.execute (MojoExecutor.java:160)
    at org.apache.maven.lifecycle.internal.LifecycleModuleBuilder.buildProject (LifecycleModuleBuilder.java:105)
    at org.apache.maven.lifecycle.internal.LifecycleModuleBuilder.buildProject (LifecycleModuleBuilder.java:73)
    at org.apache.maven.lifecycle.internal.builder.singlethreaded.SingleThreadedBuilder.build (SingleThreadedBuilder.java:53)
    at org.apache.maven.lifecycle.internal.LifecycleStarter.execute (LifecycleStarter.java:118)
    at org.apache.maven.DefaultMaven.doExecute (DefaultMaven.java:261)
    at org.apache.maven.DefaultMaven.doExecute (DefaultMaven.java:173)
    at org.apache.maven.DefaultMaven.execute (DefaultMaven.java:101)
    at org.apache.maven.cli.MavenCli.execute (MavenCli.java:827)
    at org.apache.maven.cli.MavenCli.doMain (MavenCli.java:272)
    at org.apache.maven.cli.MavenCli.main (MavenCli.java:195)
    at sun.reflect.NativeMethodAccessorImpl.invoke0 (Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke (NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke (DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke (Method.java:498)
    at org.codehaus.plexus.classworlds.launcher.Launcher.launchEnhanced (Launcher.java:282)
    at org.codehaus.plexus.classworlds.launcher.Launcher.launch (Launcher.java:225)
    at org.codehaus.plexus.classworlds.launcher.Launcher.mainWithExitCode (Launcher.java:406)
    at org.codehaus.plexus.classworlds.launcher.Launcher.main (Launcher.java:347)
Caused by: org.apache.maven.plugin.MojoExecutionException: Error generating versions-maven-plugin:2.15.0:dependency-updates-aggregate-report report
    at org.apache.maven.plugins.site.render.SiteMojo.execute (SiteMojo.java:153)
    at org.apache.maven.plugin.DefaultBuildPluginManager.executeMojo (DefaultBuildPluginManager.java:126)
    at org.apache.maven.lifecycle.internal.MojoExecutor.doExecute2 (MojoExecutor.java:342)
    at org.apache.maven.lifecycle.internal.MojoExecutor.doExecute (MojoExecutor.java:330)
    at org.apache.maven.lifecycle.internal.MojoExecutor.execute (MojoExecutor.java:213)
    at org.apache.maven.lifecycle.internal.MojoExecutor.execute (MojoExecutor.java:175)
    at org.apache.maven.lifecycle.internal.MojoExecutor.access$000 (MojoExecutor.java:76)
    at org.apache.maven.lifecycle.internal.MojoExecutor$1.run (MojoExecutor.java:163)
    at org.apache.maven.plugin.DefaultMojosExecutionStrategy.execute (DefaultMojosExecutionStrategy.java:39)
    at org.apache.maven.lifecycle.internal.MojoExecutor.execute (MojoExecutor.java:160)
    at org.apache.maven.lifecycle.internal.LifecycleModuleBuilder.buildProject (LifecycleModuleBuilder.java:105)
    at org.apache.maven.lifecycle.internal.LifecycleModuleBuilder.buildProject (LifecycleModuleBuilder.java:73)
    at org.apache.maven.lifecycle.internal.builder.singlethreaded.SingleThreadedBuilder.build (SingleThreadedBuilder.java:53)
    at org.apache.maven.lifecycle.internal.LifecycleStarter.execute (LifecycleStarter.java:118)
    at org.apache.maven.DefaultMaven.doExecute (DefaultMaven.java:261)
    at org.apache.maven.DefaultMaven.doExecute (DefaultMaven.java:173)
    at org.apache.maven.DefaultMaven.execute (DefaultMaven.java:101)
    at org.apache.maven.cli.MavenCli.execute (MavenCli.java:827)
    at org.apache.maven.cli.MavenCli.doMain (MavenCli.java:272)
    at org.apache.maven.cli.MavenCli.main (MavenCli.java:195)
    at sun.reflect.NativeMethodAccessorImpl.invoke0 (Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke (NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke (DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke (Method.java:498)
    at org.codehaus.plexus.classworlds.launcher.Launcher.launchEnhanced (Launcher.java:282)
    at org.codehaus.plexus.classworlds.launcher.Launcher.launch (Launcher.java:225)
    at org.codehaus.plexus.classworlds.launcher.Launcher.mainWithExitCode (Launcher.java:406)
    at org.codehaus.plexus.classworlds.launcher.Launcher.main (Launcher.java:347)
Caused by: org.apache.maven.doxia.siterenderer.RendererException: Error generating versions-maven-plugin:2.15.0:dependency-updates-aggregate-report report
    at org.apache.maven.plugins.site.render.ReportDocumentRenderer.renderDocument (ReportDocumentRenderer.java:247)
    at org.apache.maven.doxia.siterenderer.DefaultSiteRenderer.render (DefaultSiteRenderer.java:348)
    at org.apache.maven.plugins.site.render.SiteMojo.renderLocale (SiteMojo.java:194)
    at org.apache.maven.plugins.site.render.SiteMojo.execute (SiteMojo.java:143)
    at org.apache.maven.plugin.DefaultBuildPluginManager.executeMojo (DefaultBuildPluginManager.java:126)
    at org.apache.maven.lifecycle.internal.MojoExecutor.doExecute2 (MojoExecutor.java:342)
    at org.apache.maven.lifecycle.internal.MojoExecutor.doExecute (MojoExecutor.java:330)
    at org.apache.maven.lifecycle.internal.MojoExecutor.execute (MojoExecutor.java:213)
    at org.apache.maven.lifecycle.internal.MojoExecutor.execute (MojoExecutor.java:175)
    at org.apache.maven.lifecycle.internal.MojoExecutor.access$000 (MojoExecutor.java:76)
    at org.apache.maven.lifecycle.internal.MojoExecutor$1.run (MojoExecutor.java:163)
    at org.apache.maven.plugin.DefaultMojosExecutionStrategy.execute (DefaultMojosExecutionStrategy.java:39)
    at org.apache.maven.lifecycle.internal.MojoExecutor.execute (MojoExecutor.java:160)
    at org.apache.maven.lifecycle.internal.LifecycleModuleBuilder.buildProject (LifecycleModuleBuilder.java:105)
    at org.apache.maven.lifecycle.internal.LifecycleModuleBuilder.buildProject (LifecycleModuleBuilder.java:73)
    at org.apache.maven.lifecycle.internal.builder.singlethreaded.SingleThreadedBuilder.build (SingleThreadedBuilder.java:53)
    at org.apache.maven.lifecycle.internal.LifecycleStarter.execute (LifecycleStarter.java:118)
    at org.apache.maven.DefaultMaven.doExecute (DefaultMaven.java:261)
    at org.apache.maven.DefaultMaven.doExecute (DefaultMaven.java:173)
    at org.apache.maven.DefaultMaven.execute (DefaultMaven.java:101)
    at org.apache.maven.cli.MavenCli.execute (MavenCli.java:827)
    at org.apache.maven.cli.MavenCli.doMain (MavenCli.java:272)
    at org.apache.maven.cli.MavenCli.main (MavenCli.java:195)
    at sun.reflect.NativeMethodAccessorImpl.invoke0 (Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke (NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke (DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke (Method.java:498)
    at org.codehaus.plexus.classworlds.launcher.Launcher.launchEnhanced (Launcher.java:282)
    at org.codehaus.plexus.classworlds.launcher.Launcher.launch (Launcher.java:225)
    at org.codehaus.plexus.classworlds.launcher.Launcher.mainWithExitCode (Launcher.java:406)
    at org.codehaus.plexus.classworlds.launcher.Launcher.main (Launcher.java:347)
Caused by: java.lang.NullPointerException
    at org.apache.maven.artifact.DefaultArtifact.equals (DefaultArtifact.java:318)
    at org.apache.commons.lang3.builder.EqualsBuilder.append (EqualsBuilder.java:649)
    at org.codehaus.mojo.versions.api.ArtifactVersions.equals (ArtifactVersions.java:123)
    at java.util.Objects.equals (Objects.java:59)
    at org.apache.commons.lang3.tuple.Triple.equals (Triple.java:138)
    at java.util.HashMap.computeIfAbsent (HashMap.java:1115)
    at org.codehaus.mojo.versions.api.ArtifactVersionsCache.get (ArtifactVersionsCache.java:61)
    at org.codehaus.mojo.versions.reporting.AbstractVersionsReportRenderer.renderSummaryTableRow (AbstractVersionsReportRenderer.java:222)
    at org.codehaus.mojo.versions.reporting.AbstractVersionsReportRenderer.lambda$renderSummaryTable$0 (AbstractVersionsReportRenderer.java:198)
    at java.util.TreeMap.forEach (TreeMap.java:1005)
    at org.codehaus.mojo.versions.reporting.AbstractVersionsReportRenderer.renderSummaryTable (AbstractVersionsReportRenderer.java:198)
    at org.codehaus.mojo.versions.reporting.DependencyUpdatesReportRenderer.renderTable (DependencyUpdatesReportRenderer.java:75)
    at org.codehaus.mojo.versions.reporting.DependencyUpdatesReportRenderer.renderSummaryTable (DependencyUpdatesReportRenderer.java:53)
    at org.codehaus.mojo.versions.reporting.AbstractVersionsReportRenderer.renderBody (AbstractVersionsReportRenderer.java:93)
    at org.apache.maven.reporting.AbstractMavenReportRenderer.render (AbstractMavenReportRenderer.java:82)
    at org.codehaus.mojo.versions.AbstractDependencyUpdatesReportMojo.renderReport (AbstractDependencyUpdatesReportMojo.java:279)
    at org.codehaus.mojo.versions.AbstractDependencyUpdatesReportMojo.doGenerateReport (AbstractDependencyUpdatesReportMojo.java:176)
    at org.codehaus.mojo.versions.AbstractVersionsReport.executeReport (AbstractVersionsReport.java:209)
    at org.apache.maven.reporting.AbstractMavenReport.generate (AbstractMavenReport.java:289)
    at org.apache.maven.plugins.site.render.ReportDocumentRenderer.renderDocument (ReportDocumentRenderer.java:226)
    at org.apache.maven.doxia.siterenderer.DefaultSiteRenderer.render (DefaultSiteRenderer.java:348)
    at org.apache.maven.plugins.site.render.SiteMojo.renderLocale (SiteMojo.java:194)
    at org.apache.maven.plugins.site.render.SiteMojo.execute (SiteMojo.java:143)
    at org.apache.maven.plugin.DefaultBuildPluginManager.executeMojo (DefaultBuildPluginManager.java:126)
    at org.apache.maven.lifecycle.internal.MojoExecutor.doExecute2 (MojoExecutor.java:342)
    at org.apache.maven.lifecycle.internal.MojoExecutor.doExecute (MojoExecutor.java:330)
    at org.apache.maven.lifecycle.internal.MojoExecutor.execute (MojoExecutor.java:213)
    at org.apache.maven.lifecycle.internal.MojoExecutor.execute (MojoExecutor.java:175)
    at org.apache.maven.lifecycle.internal.MojoExecutor.access$000 (MojoExecutor.java:76)
    at org.apache.maven.lifecycle.internal.MojoExecutor$1.run (MojoExecutor.java:163)
    at org.apache.maven.plugin.DefaultMojosExecutionStrategy.execute (DefaultMojosExecutionStrategy.java:39)
    at org.apache.maven.lifecycle.internal.MojoExecutor.execute (MojoExecutor.java:160)
    at org.apache.maven.lifecycle.internal.LifecycleModuleBuilder.buildProject (LifecycleModuleBuilder.java:105)
    at org.apache.maven.lifecycle.internal.LifecycleModuleBuilder.buildProject (LifecycleModuleBuilder.java:73)
    at org.apache.maven.lifecycle.internal.builder.singlethreaded.SingleThreadedBuilder.build (SingleThreadedBuilder.java:53)
    at org.apache.maven.lifecycle.internal.LifecycleStarter.execute (LifecycleStarter.java:118)
    at org.apache.maven.DefaultMaven.doExecute (DefaultMaven.java:261)
    at org.apache.maven.DefaultMaven.doExecute (DefaultMaven.java:173)
    at org.apache.maven.DefaultMaven.execute (DefaultMaven.java:101)
    at org.apache.maven.cli.MavenCli.execute (MavenCli.java:827)
    at org.apache.maven.cli.MavenCli.doMain (MavenCli.java:272)
    at org.apache.maven.cli.MavenCli.main (MavenCli.java:195)
    at sun.reflect.NativeMethodAccessorImpl.invoke0 (Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke (NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke (DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke (Method.java:498)
    at org.codehaus.plexus.classworlds.launcher.Launcher.launchEnhanced (Launcher.java:282)
    at org.codehaus.plexus.classworlds.launcher.Launcher.launch (Launcher.java:225)
    at org.codehaus.plexus.classworlds.launcher.Launcher.mainWithExitCode (Launcher.java:406)
    at org.codehaus.plexus.classworlds.launcher.Launcher.main (Launcher.java:347)

This seems to happen because the DefaultArtifact for org.codehaus.mojo:versions-maven-plugin:jar:[2.10.0-SNAPSHOT,2.999.0):test has a version field that is null, so a.getVersion().equals(version) in its equals method throws a NullPointerException...

I reported this as MNG-7780, but I wonder if this plugin can do anything to guard against this problem...

[andrzejj0]

I think it might be #925, fixed by #926 (I have not checked that).

Can you try the latest snapshot?

[TobiX]

Still triggers with the latest SNAPSHOT, unfortunately.

[andrzejj0]

Yes, it looks like it's the same bug, just not fixed in this mojo. As a workaround, -DprocessDependencyManagement=false needs to be used until this is patched.

I see where the problem is.

[andrzejj0]

So I am not exactly sure what the "contract" is for Artifact and, in particular, for DefaultArtifact. Throughout the plugin, we do build an "Artifact" from raw model, with no version set whatsoever where Maven probably would set a version taken from dependency/plugin management or from parent.

Maybe a different concrete class of Artifact could be used there, but that would be a pretty sizeable refactoring job... Strange enough, DefaultArtifact::hashCode does make a provision from an empty version whereas ::equals does not.

I'll patch the problem at our end. Regarding the Maven ticket, even if they decide to make that fool-proof, that would mean that we would need to restrict Maven version in the plugin since Maven dependencies are linked with provided scope.