Resources handling is broken when there is a .mvn folder

[tmortagne]

When there is a .mvn folder (it does not even need to contain anything) at the root of the imported module or multi modules tree, resources files are not copied to target/classes anymore.

To reproduce:

• download and extract
  project-with-resources.zip
• import it as Maven project

-> among other things, a target/classes is generated, but it does not contain the expected resource file named file.txt

• delete the .mvn folder
• right click on the project -> Maven -> Update Project... -> OK

-> the file target/classes/file.txt appear

I did not have this problem in Eclipse 2022-06 (I had other problems with 2022-09 like #1005, so I did not really use it much).

Eclipse version: 2022-12
Maven Integration for Eclipse version: 2.1.2.20221130-2239

[HannesWell]

Thanks for the detailed report. I can reproduce the issue with the current master.
It even sufficient when you just clean the project (and auto-build it) after having deleted the .mvn folder. Adding the .mvn folder back prevents the copying again.
I'm about to investigate it.

[HannesWell]

Was able to record the following exception that is unfortunately swallowed at the moment (I think that should change and at least end up in the Error-log if not even causing a warning or error):

org.apache.maven.plugin.PluginExecutionException: Execution default-resources of goal org.apache.maven.plugins:maven-resources-plugin:2.6:resources failed: Unable to load the mojo 'resources' (or one of its required components) from the plugin 'org.apache.maven.plugins:maven-resources-plugin:2.6'
	at org.apache.maven.plugin.DefaultBuildPluginManager.executeMojo(DefaultBuildPluginManager.java:156)
	at org.eclipse.m2e.core.internal.embedder.MavenExecutionContext.executeMojo(MavenExecutionContext.java:331)
	at org.eclipse.m2e.core.internal.embedder.MavenExecutionContext.lambda$0(MavenExecutionContext.java:290)
	at org.eclipse.m2e.core.internal.embedder.MavenExecutionContext.executeBare(MavenExecutionContext.java:364)
	at org.eclipse.m2e.core.internal.embedder.MavenExecutionContext.execute(MavenExecutionContext.java:274)
	at org.eclipse.m2e.core.internal.embedder.MavenExecutionContext.execute(MavenExecutionContext.java:289)
	at org.eclipse.m2e.core.project.configurator.MojoExecutionBuildParticipant.build(MojoExecutionBuildParticipant.java:57)
	at org.eclipse.m2e.core.internal.builder.MavenBuilderImpl.build(MavenBuilderImpl.java:135)
	at org.eclipse.m2e.core.internal.builder.MavenBuilder$1.method(MavenBuilder.java:167)
	at org.eclipse.m2e.core.internal.builder.MavenBuilder$1.method(MavenBuilder.java:1)
	at org.eclipse.m2e.core.internal.builder.MavenBuilder$BuildMethod.lambda$1(MavenBuilder.java:112)
	at org.eclipse.m2e.core.internal.embedder.MavenExecutionContext.executeBare(MavenExecutionContext.java:364)
	at org.eclipse.m2e.core.internal.embedder.MavenExecutionContext.execute(MavenExecutionContext.java:227)
	at org.eclipse.m2e.core.internal.builder.MavenBuilder$BuildMethod.lambda$0(MavenBuilder.java:103)
	at org.eclipse.m2e.core.internal.embedder.MavenExecutionContext.executeBare(MavenExecutionContext.java:364)
	at org.eclipse.m2e.core.internal.embedder.MavenExecutionContext.execute(MavenExecutionContext.java:274)
	at org.eclipse.m2e.core.internal.embedder.MavenExecutionContext.execute(MavenExecutionContext.java:213)
	at org.eclipse.m2e.core.internal.builder.MavenBuilder$BuildMethod.execute(MavenBuilder.java:86)
	at org.eclipse.m2e.core.internal.builder.MavenBuilder.build(MavenBuilder.java:196)
	at org.eclipse.core.internal.events.BuildManager$2.run(BuildManager.java:1020)
	at org.eclipse.core.runtime.SafeRunner.run(SafeRunner.java:45)
	at org.eclipse.core.internal.events.BuildManager.basicBuild(BuildManager.java:247)
	at org.eclipse.core.internal.events.BuildManager.basicBuild(BuildManager.java:303)
	at org.eclipse.core.internal.events.BuildManager$1.run(BuildManager.java:392)
	at org.eclipse.core.runtime.SafeRunner.run(SafeRunner.java:45)
	at org.eclipse.core.internal.events.BuildManager.basicBuild(BuildManager.java:395)
	at org.eclipse.core.internal.events.BuildManager.basicBuildLoop(BuildManager.java:506)
	at org.eclipse.core.internal.events.BuildManager.basicBuildLoop(BuildManager.java:454)
	at org.eclipse.core.internal.events.BuildManager.build(BuildManager.java:536)
	at org.eclipse.core.internal.events.AutoBuildJob.doBuild(AutoBuildJob.java:161)
	at org.eclipse.core.internal.events.AutoBuildJob.run(AutoBuildJob.java:255)
	at org.eclipse.core.internal.jobs.Worker.run(Worker.java:63)
Caused by: org.apache.maven.plugin.PluginContainerException: Unable to load the mojo 'resources' (or one of its required components) from the plugin 'org.apache.maven.plugins:maven-resources-plugin:2.6'
	at org.apache.maven.plugin.internal.DefaultMavenPluginManager.getConfiguredMojo(DefaultMavenPluginManager.java:557)
	at org.apache.maven.plugin.DefaultBuildPluginManager.executeMojo(DefaultBuildPluginManager.java:124)
	... 31 more
Caused by: org.codehaus.plexus.component.repository.exception.ComponentLookupException: java.util.NoSuchElementException
      role: org.apache.maven.plugin.Mojo
  roleHint: org.apache.maven.plugins:maven-resources-plugin:2.6:resources
	at org.codehaus.plexus.DefaultPlexusContainer.lookup(DefaultPlexusContainer.java:267)
	at org.codehaus.plexus.DefaultPlexusContainer.lookup(DefaultPlexusContainer.java:255)
	at org.apache.maven.plugin.internal.DefaultMavenPluginManager.getConfiguredMojo(DefaultMavenPluginManager.java:520)
	... 32 more
Caused by: java.util.NoSuchElementException
	at org.eclipse.sisu.plexus.RealmFilteredBeans$FilteredItr.next(RealmFilteredBeans.java:118)
	at org.eclipse.sisu.plexus.RealmFilteredBeans$FilteredItr.next(RealmFilteredBeans.java:1)
	at org.eclipse.sisu.plexus.DefaultPlexusBeans$Itr.next(DefaultPlexusBeans.java:76)
	at org.eclipse.sisu.plexus.DefaultPlexusBeans$Itr.next(DefaultPlexusBeans.java:1)
	at org.codehaus.plexus.DefaultPlexusContainer.lookup(DefaultPlexusContainer.java:263)
	... 34 more

One can catch that by setting a break-point in:

m2e-core/org.eclipse.m2e.core/src/org/eclipse/m2e/core/internal/embedder/MavenExecutionContext.java

Line 333 in 6c5ba5d

session.getResult().addException(ex);

Actually that exception should be propagated (wrapped in a CoreException). I think that can be part of the fix.

[laeubi]

@HannesWell can you share your example as a test in m2ecore? I want to take a look at this.

[HannesWell]

@HannesWell can you share your example as a test in m2ecore? I want to take a look at this.

Done in #1160.

[martinlippert]

Any idea in which release the fix for this will ship? And a rough idea when that release will ship?

[laeubi]

Please try out the latest snapshot build, you can use this p2 repository:

https://download.eclipse.org/technology/m2e/snapshots/latest/

[martinlippert]

Yeah, tried the snapshot already, works all fine. Many many thanks for fixing this, btw, very much appreciated. Just looking at a release for inclusion in one of our next builds here... :-)