netty: mvn compile fails on netty-transport-native-epoll

The following happens with Maven 3.3 as well as 3.5.

mvn compile fails with the following error when it run it from the root of the project. It succeeds when I run mvn -pl transport-native-epoll compile or run mvn compile from inside the transport-native-epoll directory. mvn install always works.

The same error happens when I compile Netty in the IDE (Eclipse).

[INFO] ------------------------------------------------------------------------
[INFO] Reactor Summary:
[INFO] 
[INFO] Netty .............................................. SUCCESS [  4.532 s]
[INFO] Netty/Common ....................................... SUCCESS [  5.806 s]
[INFO] Netty/Buffer ....................................... SUCCESS [  4.636 s]
[INFO] Netty/Resolver ..................................... SUCCESS [  1.353 s]
[INFO] Netty/Transport .................................... SUCCESS [  3.613 s]
[INFO] Netty/Codec ........................................ SUCCESS [  3.779 s]
[INFO] Netty/Codec/DNS .................................... SUCCESS [  1.853 s]
[INFO] Netty/Codec/HAProxy ................................ SUCCESS [  1.350 s]
[INFO] Netty/Handler ...................................... SUCCESS [  3.518 s]
[INFO] Netty/Codec/HTTP ................................... SUCCESS [  4.044 s]
[INFO] Netty/Codec/HTTP2 .................................. SUCCESS [  3.379 s]
[INFO] Netty/Codec/Memcache ............................... SUCCESS [  1.305 s]
[INFO] Netty/Codec/MQTT ................................... SUCCESS [  1.499 s]
[INFO] Netty/Codec/Redis .................................. SUCCESS [  1.275 s]
[INFO] Netty/Codec/SMTP ................................... SUCCESS [  1.309 s]
[INFO] Netty/Codec/Socks .................................. SUCCESS [  1.609 s]
[INFO] Netty/Codec/Stomp .................................. SUCCESS [  1.265 s]
[INFO] Netty/Codec/XML .................................... SUCCESS [  1.104 s]
[INFO] Netty/Handler/Proxy ................................ SUCCESS [  1.429 s]
[INFO] Netty/Resolver/DNS ................................. SUCCESS [  1.753 s]
[INFO] Netty/Transport/RXTX ............................... SUCCESS [  0.975 s]
[INFO] Netty/Transport/SCTP ............................... SUCCESS [  1.363 s]
[INFO] Netty/Transport/UDT ................................ SUCCESS [  1.270 s]
[INFO] Netty/Example ...................................... SUCCESS [  3.112 s]
[INFO] Netty/Transport/Native/Unix/Common ................. SUCCESS [  1.967 s]
[INFO] Netty/Testsuite .................................... SUCCESS [  2.199 s]
[INFO] Netty/Transport/Native/Unix/Common/Tests ........... SUCCESS [  0.732 s]
[INFO] Netty/Transport/Native/Epoll ....................... FAILURE [  0.498 s]
[INFO] Netty/All-in-One ................................... SKIPPED
[INFO] Netty/Dev-Tools .................................... SKIPPED
[INFO] Netty/Tarball ...................................... SKIPPED
[INFO] Netty/Transport/Native/KQueue ...................... SKIPPED
[INFO] Netty/Testsuite/Autobahn ........................... SKIPPED
[INFO] Netty/Testsuite/OSGI ............................... SKIPPED
[INFO] Netty/Microbench ................................... SKIPPED
[INFO] Netty/BOM .......................................... SKIPPED
[INFO] ------------------------------------------------------------------------
[INFO] BUILD FAILURE
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 01:03 min
[INFO] Finished at: 2017-08-14T11:14:28-04:00
[INFO] Final Memory: 41M/490M
[INFO] ------------------------------------------------------------------------
[ERROR] Failed to execute goal org.apache.maven.plugins:maven-dependency-plugin:2.10:unpack-dependencies (unpack) on project netty-transport-native-epoll: Artifact has not been packaged yet. When used on reactor artifact, unpack should be executed after packaging: see MDEP-98. -> [Help 1]
org.apache.maven.lifecycle.LifecycleExecutionException: Failed to execute goal org.apache.maven.plugins:maven-dependency-plugin:2.10:unpack-dependencies (unpack) on project netty-transport-native-epoll: Artifact has not been packaged yet. When used on reactor artifact, unpack should be executed after packaging: see MDEP-98.
	at org.apache.maven.lifecycle.internal.MojoExecutor.execute(MojoExecutor.java:213)
	at org.apache.maven.lifecycle.internal.MojoExecutor.execute(MojoExecutor.java:154)
	at org.apache.maven.lifecycle.internal.MojoExecutor.execute(MojoExecutor.java:146)
	at org.apache.maven.lifecycle.internal.LifecycleModuleBuilder.buildProject(LifecycleModuleBuilder.java:117)
	at org.apache.maven.lifecycle.internal.LifecycleModuleBuilder.buildProject(LifecycleModuleBuilder.java:81)
	at org.apache.maven.lifecycle.internal.builder.singlethreaded.SingleThreadedBuilder.build(SingleThreadedBuilder.java:51)
	at org.apache.maven.lifecycle.internal.LifecycleStarter.execute(LifecycleStarter.java:128)
	at org.apache.maven.DefaultMaven.doExecute(DefaultMaven.java:309)
	at org.apache.maven.DefaultMaven.doExecute(DefaultMaven.java:194)
	at org.apache.maven.DefaultMaven.execute(DefaultMaven.java:107)
	at org.apache.maven.cli.MavenCli.execute(MavenCli.java:993)
	at org.apache.maven.cli.MavenCli.doMain(MavenCli.java:345)
	at org.apache.maven.cli.MavenCli.main(MavenCli.java:191)
	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:289)
	at org.codehaus.plexus.classworlds.launcher.Launcher.launch(Launcher.java:229)
	at org.codehaus.plexus.classworlds.launcher.Launcher.mainWithExitCode(Launcher.java:415)
	at org.codehaus.plexus.classworlds.launcher.Launcher.main(Launcher.java:356)
Caused by: org.apache.maven.plugin.MojoExecutionException: Artifact has not been packaged yet. When used on reactor artifact, unpack should be executed after packaging: see MDEP-98.
	at org.apache.maven.plugin.dependency.AbstractDependencyMojo.unpack(AbstractDependencyMojo.java:265)
	at org.apache.maven.plugin.dependency.fromDependencies.UnpackDependenciesMojo.doExecute(UnpackDependenciesMojo.java:91)
	at org.apache.maven.plugin.dependency.AbstractDependencyMojo.execute(AbstractDependencyMojo.java:167)
	at org.apache.maven.plugin.DefaultBuildPluginManager.executeMojo(DefaultBuildPluginManager.java:134)
	at org.apache.maven.lifecycle.internal.MojoExecutor.execute(MojoExecutor.java:208)
	... 20 more
[ERROR] 
[ERROR] Re-run Maven using the -X switch to enable full debug logging.
[ERROR] 
[ERROR] For more information about the errors and possible solutions, please read the following articles:
[ERROR] [Help 1] http://cwiki.apache.org/confluence/display/MAVEN/MojoExecutionException
[ERROR] 
[ERROR] After correcting the problems, you can resume the build with the command
[ERROR]   mvn <goals> -rf :netty-transport-native-epoll

Expected behavior

Actual behavior

Steps to reproduce

Minimal yet complete reproducer code (or URL to code)

Netty version

JVM version (e.g. java -version)

$ java -version
openjdk version "1.8.0_144"
OpenJDK Runtime Environment (build 1.8.0_144-b01)
OpenJDK 64-Bit Server VM (build 25.144-b01, mixed mode)

OS version (e.g. uname -a)

$ uname -a
Linux ardverk 4.12.6-1-ARCH #1 SMP PREEMPT Sat Aug 12 09:16:22 CEST 2017 x86_64 GNU/Linux