fails in eclipse

[Andrei-Pozolotin]

https://wiki.eclipse.org/M2E_compatible_maven_plugins

1. any attempt to enable flatten in eclipse:

<pluginExecution>
	<pluginExecutionFilter>
		<groupId>org.codehaus.mojo</groupId>
        	<artifactId>flatten-maven-plugin</artifactId>
		<versionRange>[0,)</versionRange>
		<goals>
			<goal>flatten</goal>
		</goals>
	</pluginExecutionFilter>
	<action>
		<execute>
			<runOnIncremental>false</runOnIncremental>
                        <runOnConfiguration>true></runOnConfiguration>
		</execute>
	</action>
</pluginExecution>

2. results in plugin error java.lang.NullPointerException:

Description	Resource	Path	Location	Type
Execution flatten of goal org.codehaus.mojo:flatten-maven-plugin:1.0.1:flatten failed. (org.codehaus.mojo:flatten-maven-plugin:1.0.1:flatten:flatten:package)

org.apache.maven.plugin.PluginExecutionException: Execution flatten of goal org.codehaus.mojo:flatten-maven-plugin:1.0.1:flatten failed.
	at org.apache.maven.plugin.DefaultBuildPluginManager.executeMojo(DefaultBuildPluginManager.java:145)
	at org.eclipse.m2e.core.internal.embedder.MavenImpl.execute(MavenImpl.java:331)
	at org.eclipse.m2e.core.internal.embedder.MavenImpl$11.call(MavenImpl.java:1362)
	at org.eclipse.m2e.core.internal.embedder.MavenImpl$11.call(MavenImpl.java:1)
	at org.eclipse.m2e.core.internal.embedder.MavenExecutionContext.executeBare(MavenExecutionContext.java:177)
	at org.eclipse.m2e.core.internal.embedder.MavenExecutionContext.execute(MavenExecutionContext.java:112)
	at org.eclipse.m2e.core.internal.embedder.MavenImpl.execute(MavenImpl.java:1360)
	at org.eclipse.m2e.core.project.configurator.MojoExecutionBuildParticipant.build(MojoExecutionBuildParticipant.java:52)
	at org.eclipse.m2e.core.internal.builder.MavenBuilderImpl.build(MavenBuilderImpl.java:137)
	at org.eclipse.m2e.core.internal.builder.MavenBuilder$1.method(MavenBuilder.java:172)
	at org.eclipse.m2e.core.internal.builder.MavenBuilder$1.method(MavenBuilder.java:1)
	at org.eclipse.m2e.core.internal.builder.MavenBuilder$BuildMethod$1$1.call(MavenBuilder.java:115)
	at org.eclipse.m2e.core.internal.embedder.MavenExecutionContext.executeBare(MavenExecutionContext.java:177)
	at org.eclipse.m2e.core.internal.embedder.MavenExecutionContext.execute(MavenExecutionContext.java:112)
	at org.eclipse.m2e.core.internal.builder.MavenBuilder$BuildMethod$1.call(MavenBuilder.java:105)
	at org.eclipse.m2e.core.internal.embedder.MavenExecutionContext.executeBare(MavenExecutionContext.java:177)
	at org.eclipse.m2e.core.internal.embedder.MavenExecutionContext.execute(MavenExecutionContext.java:151)
	at org.eclipse.m2e.core.internal.embedder.MavenExecutionContext.execute(MavenExecutionContext.java:99)
	at org.eclipse.m2e.core.internal.builder.MavenBuilder$BuildMethod.execute(MavenBuilder.java:86)
	at org.eclipse.m2e.core.internal.builder.MavenBuilder.build(MavenBuilder.java:200)
	at org.eclipse.core.internal.events.BuildManager$2.run(BuildManager.java:735)
	at org.eclipse.core.runtime.SafeRunner.run(SafeRunner.java:42)
	at org.eclipse.core.internal.events.BuildManager.basicBuild(BuildManager.java:206)
	at org.eclipse.core.internal.events.BuildManager.basicBuild(BuildManager.java:246)
	at org.eclipse.core.internal.events.BuildManager$1.run(BuildManager.java:301)
	at org.eclipse.core.runtime.SafeRunner.run(SafeRunner.java:42)
	at org.eclipse.core.internal.events.BuildManager.basicBuild(BuildManager.java:304)
	at org.eclipse.core.internal.events.BuildManager.basicBuildLoop(BuildManager.java:360)
	at org.eclipse.core.internal.events.BuildManager.build(BuildManager.java:383)
	at org.eclipse.core.internal.events.AutoBuildJob.doBuild(AutoBuildJob.java:142)
	at org.eclipse.core.internal.events.AutoBuildJob.run(AutoBuildJob.java:232)
	at org.eclipse.core.internal.jobs.Worker.run(Worker.java:56)
Caused by: java.lang.NullPointerException
	at org.codehaus.mojo.flatten.model.resolution.ReactorModelPool.addProjects(ReactorModelPool.java:46)
	at org.codehaus.mojo.flatten.model.resolution.FlattenModelResolver.<init>(FlattenModelResolver.java:70)
	at org.codehaus.mojo.flatten.FlattenMojo.createModelBuildingRequest(FlattenMojo.java:684)
	at org.codehaus.mojo.flatten.FlattenMojo.createFlattenedPom(FlattenMojo.java:447)
	at org.codehaus.mojo.flatten.FlattenMojo.execute(FlattenMojo.java:313)
	at org.apache.maven.plugin.DefaultBuildPluginManager.executeMojo(DefaultBuildPluginManager.java:134)
	... 31 more

[famod]

Same here, Eclipse Neon.3 with m2e 1.7.1.

[hohwille]

I am using flatten plugin in all my projects since years with Eclipse and m2e without issues.
Sorry that you are facing problems.

[hohwille]

flatten-maven-plugin/src/main/java/org/codehaus/mojo/flatten/model/resolution/ReactorModelPool.java

Line 46 in 071277c

for ( MavenProject project : projects )

So your list of maven projects is null? This seems to me like a core bug in Eclipse/m2e rather than flatten. WDYT?
@Andrei-Pozolotin you have already found the bug and resolved it? Not interested in contributing and joining forces?

[famod]

Still a problem with plugin version 1.1.0, Eclipse 2019-03 (4.11.0) and m2e 1.11.0.

[famod]

It turns out that (although a null allProjects list is indeed strange) a simple null check is enough to make flattening work in eclipse. I will create a PR for this soon.

PS: m2e doesn't seem to need a "ci friendly" flattening because it is able to resolve ${revision} on its own. It probably needs the relativePath info, but I haven't tried without that.

[creamteam-de]

With plugin version 1.1.0, 2019-06 (4.12.0) and m2e 1.12.0.20190529-1916 error occurs too, is there any plan to have a new release with PR? Thanks!