NPE when updating Maven project

[kwin]

The following NPE is thrown when updating a Maven project

java.lang.NullPointerException: Cannot invoke "org.eclipse.m2e.core.project.IMavenProjectFacade.getArtifactKey()" because "facade" is null
	at org.eclipse.m2e.core.internal.project.registry.MavenProjectCache.updateMavenProject(MavenProjectCache.java:119)
	at org.eclipse.m2e.core.internal.project.registry.ProjectRegistryManager.refresh(ProjectRegistryManager.java:476)
	at org.eclipse.m2e.core.internal.project.registry.ProjectRegistryManager.refresh(ProjectRegistryManager.java:367)
	at org.eclipse.m2e.core.internal.project.registry.ProjectRegistryManager.refresh(ProjectRegistryManager.java:319)
	at org.eclipse.m2e.core.internal.project.ProjectConfigurationManager.updateProjectConfiguration0(ProjectConfigurationManager.java:388)
	at org.eclipse.m2e.core.internal.project.ProjectConfigurationManager.lambda$3(ProjectConfigurationManager.java:340)
	at org.eclipse.m2e.core.internal.embedder.MavenExecutionContext.executeBare(MavenExecutionContext.java:394)
	at org.eclipse.m2e.core.internal.embedder.MavenExecutionContext.execute(MavenExecutionContext.java:275)
	at org.eclipse.m2e.core.internal.embedder.MavenExecutionContext.execute(MavenExecutionContext.java:214)
	at org.eclipse.m2e.core.internal.embedder.MavenImpl.execute(MavenImpl.java:1097)
	at org.eclipse.m2e.core.internal.project.ProjectConfigurationManager.updateProjectConfiguration(ProjectConfigurationManager.java:339)
	at org.eclipse.m2e.core.ui.internal.UpdateMavenProjectJob.runInWorkspace(UpdateMavenProjectJob.java:80)
	at org.eclipse.core.internal.resources.InternalWorkspaceJob.run(InternalWorkspaceJob.java:43)
	at org.eclipse.core.internal.jobs.Worker.run(Worker.java:63)

This happens with 2023-09 with m2e 2.4.100.

[kwin]

This can only happen if newFacade is set to null in

m2e-core/org.eclipse.m2e.core/src/org/eclipse/m2e/core/internal/project/registry/ProjectRegistryManager.java

Line 467 in 0d7583d

newFacade = readMavenProjectFacades(Collections.singletonList(pom), newState, context, monitor).get(pom);

(either due to the returned map being empty or at least not containing an entry for the POM)

[HannesWell]

Can you somehow reproduce this in a debugged Eclipse?

[kwin]

Unfortunately I cannot reproduce. However error handling should be improved so that a more meaningful exception is thrown.

[HannesWell]

However error handling should be improved so that a more meaningful exception is thrown.

Sounds good. Can you provide a PR?

[dmatej]

Seen today on latest Eclipse IDE:

SESSION 2024-07-04 20:06:44.743 -----------------------------------------------
eclipse.buildId=4.32.0.20240606-1231
java.version=21.0.3
java.vendor=Eclipse Adoptium
BootLoader constants: OS=linux, ARCH=x86_64, WS=gtk, NL=cs_CZ
Framework arguments:  -cssTheme none -product org.eclipse.epp.package.jee.product
Command-line arguments:  -os linux -ws gtk -arch x86_64 -cssTheme none -product org.eclipse.epp.package.jee.product

This is a continuation of log file /media/data-samsung/data/dmatej/work/workspaces/glassfish/.metadata/.bak_0.log
Created Time: 2024-07-04 21:49:18.949

!ENTRY org.eclipse.core.resources 4 2 2024-07-04 21:49:18.949
!MESSAGE Problems occurred when invoking code from plug-in: "org.eclipse.core.resources".
!STACK 0
java.lang.NullPointerException: Cannot invoke "org.eclipse.m2e.core.project.IMavenProjectFacade.getArtifactKey()" because "facade" is null
	at org.eclipse.m2e.core.internal.project.registry.MavenProjectCache.invalidateProjectFacade(MavenProjectCache.java:88)
	at org.eclipse.m2e.core.internal.project.registry.MavenProjectCache.updateMavenProject(MavenProjectCache.java:116)
	at org.eclipse.m2e.core.internal.project.registry.ProjectRegistryManager.refresh(ProjectRegistryManager.java:479)
	at org.eclipse.m2e.core.internal.project.registry.ProjectRegistryManager.refresh(ProjectRegistryManager.java:370)
	at org.eclipse.m2e.core.internal.project.registry.ProjectRegistryManager.refresh(ProjectRegistryManager.java:322)
	at org.eclipse.m2e.core.internal.builder.MavenBuilder$BuildMethod.getProjectFacade(MavenBuilder.java:146)
	at org.eclipse.m2e.core.internal.builder.MavenBuilder$BuildMethod.lambda$0(MavenBuilder.java:84)
	at org.eclipse.m2e.core.internal.embedder.MavenExecutionContext.executeBare(MavenExecutionContext.java:458)
	at org.eclipse.m2e.core.internal.embedder.MavenExecutionContext.execute(MavenExecutionContext.java:339)
	at org.eclipse.m2e.core.internal.embedder.MavenExecutionContext.execute(MavenExecutionContext.java:278)
	at org.eclipse.m2e.core.internal.builder.MavenBuilder$BuildMethod.execute(MavenBuilder.java:83)
	at org.eclipse.m2e.core.internal.builder.MavenBuilder.build(MavenBuilder.java:192)
	at org.eclipse.core.internal.events.BuildManager$2.run(BuildManager.java:1077)
	at org.eclipse.core.runtime.SafeRunner.run(SafeRunner.java:47)
	at org.eclipse.core.internal.events.BuildManager.basicBuild(BuildManager.java:296)
	at org.eclipse.core.internal.events.BuildManager.basicBuild(BuildManager.java:352)
	at org.eclipse.core.internal.events.BuildManager$1.run(BuildManager.java:441)
	at org.eclipse.core.runtime.SafeRunner.run(SafeRunner.java:47)
	at org.eclipse.core.internal.events.BuildManager.basicBuild(BuildManager.java:444)
	at org.eclipse.core.internal.events.BuildManager.basicBuildLoop(BuildManager.java:555)
	at org.eclipse.core.internal.events.BuildManager.basicBuildLoop(BuildManager.java:503)
	at org.eclipse.core.internal.events.BuildManager.build(BuildManager.java:585)
	at org.eclipse.core.internal.events.AutoBuildJob.doBuild(AutoBuildJob.java:207)
	at org.eclipse.core.internal.events.AutoBuildJob.run(AutoBuildJob.java:300)
	at org.eclipse.core.internal.jobs.Worker.run(Worker.java:63)