Installing Tycho via Maven with offline flag - eclipse

Question

I want to run Tycho in an offline environment. Therefore, I mirrored a demo repository on GitHub and executed the command mvn clean install on a computer with internet access. The build succeeded, however when I try to run mvn -o install to install all dependencies in offline mode, I recieve the following exception:
C:\Users\user\Documents\MVN_Test\itp01>mvn clean -e -o install
[INFO] Error stacktraces are turned on.
[INFO] Scanning for projects...
[WARNING] No explicit target runtime environment configuration. Build is platform dependent.
[INFO] Computing target platform for MavenProject: tycho.demo.itp01:tycho.demo.itp01:1.0.0-SNAPSHOT # C:\Users\user\Documents\MVN_Test\itp01\tycho.demo.itp01\pom.xml
[INFO] Adding repository http://download.eclipse.org/releases/helios
[ERROR] Internal error: java.lang.RuntimeException: Failed to load p2 repository with ID 'helios' from location http://download.eclipse.org/releases/helios: Repository system is offline and no local cache available for http://download.eclipse.org/releases/helios -> [Help 1]
org.apache.maven.InternalErrorException: Internal error: java.lang.RuntimeException: Failed to load p2 repository with ID 'helios' from location http://download.eclipse.org/releases/helios
at org.apache.maven.DefaultMaven.execute(DefaultMaven.java:121)
at org.apache.maven.cli.MavenCli.execute(MavenCli.java:863)
at org.apache.maven.cli.MavenCli.doMain(MavenCli.java:288)
at org.apache.maven.cli.MavenCli.main(MavenCli.java:199)
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:497)
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: java.lang.RuntimeException: Failed to load p2 repository with ID 'helios' from location http://download.eclipse.org/releases/helios
at org.eclipse.tycho.p2.target.TargetPlatformFactoryImpl.loadMetadataRepository(TargetPlatformFactoryImpl.java:302)
at org.eclipse.tycho.p2.target.TargetPlatformFactoryImpl.gatherExternalInstallableUnits(TargetPlatformFactoryImpl.java:270)
at org.eclipse.tycho.p2.target.TargetPlatformFactoryImpl.createTargetPlatform(TargetPlatformFactoryImpl.java:176)
at org.eclipse.tycho.p2.target.TargetPlatformFactoryImpl.createTargetPlatform(TargetPlatformFactoryImpl.java:128)
at org.eclipse.tycho.p2.target.TargetPlatformFactoryImpl.createTargetPlatform(TargetPlatformFactoryImpl.java:1)
at org.eclipse.tycho.p2.manager.ReactorRepositoryManagerImpl.computePreliminaryTargetPlatform(ReactorRepositoryManagerImpl.java:84)
at org.eclipse.tycho.p2.resolver.P2DependencyResolver.computePreliminaryTargetPlatform(P2DependencyResolver.java:223)
at org.eclipse.tycho.core.resolver.DefaultTychoResolver.resolveProject(DefaultTychoResolver.java:109)
at org.eclipse.tycho.core.maven.TychoMavenLifecycleParticipant.afterProjectsRead(TychoMavenLifecycleParticipant.java:95)
at org.apache.maven.DefaultMaven.doExecute(DefaultMaven.java:266)
at org.apache.maven.DefaultMaven.doExecute(DefaultMaven.java:193)
at org.apache.maven.DefaultMaven.execute(DefaultMaven.java:106)
... 11 more
Caused by: org.eclipse.equinox.p2.core.ProvisionException: Repository system is offline and no local cache available for http://download.eclipse.org/releases/helios
at org.eclipse.tycho.p2.remote.RemoteRepositoryCacheManager.createCache(RemoteRepositoryCacheManager.java:57)
at org.eclipse.equinox.internal.p2.metadata.repository.SimpleMetadataRepositoryFactory.getLocalFile(SimpleMetadataRepositoryFactory.java:66)
at org.eclipse.equinox.internal.p2.metadata.repository.SimpleMetadataRepositoryFactory.load(SimpleMetadataRepositoryFactory.java:88)
at org.eclipse.equinox.internal.p2.metadata.repository.MetadataRepositoryManager.factoryLoad(MetadataRepositoryManager.java:57)
at org.eclipse.equinox.internal.p2.repository.helpers.AbstractRepositoryManager.loadRepository(AbstractRepositoryManager.java:768)
at org.eclipse.equinox.internal.p2.repository.helpers.AbstractRepositoryManager.loadRepository(AbstractRepositoryManager.java:668)
at org.eclipse.equinox.internal.p2.metadata.repository.MetadataRepositoryManager.loadRepository(MetadataRepositoryManager.java:96)
at org.eclipse.tycho.p2.remote.RemoteMetadataRepositoryManager.loadRepository(RemoteMetadataRepositoryManager.java:61)
at org.eclipse.tycho.p2.remote.RemoteMetadataRepositoryManager.loadRepository(RemoteMetadataRepositoryManager.java:53)
at org.eclipse.tycho.p2.target.TargetPlatformFactoryImpl.loadMetadataRepository(TargetPlatformFactoryImpl.java:298)
... 22 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/InternalErrorException
I have found the following information, these may be a bug:
Demo project which demonstrates offline build failure
The problem is reproducible always with the following steps:
rm -rf ~/.m2/repository
unzip demo-project.zip
cd mvn-demo-parent/releng
mvn clean install
Build succeeds
mvn clean -o clean install
Build fails because "Repository system is offline and no local cache available for http:// download.eclipse.org/releases/mars"

Answer 1

From Bug 474885 - Build with -o flag fails with "Failed to resolve target definition" message:
This was a bug in tycho 0.24.0 and fixed in Tycho 0.25.0.
To use tycho 0.25.0 From Tycho/Release Notes/0.25
Tycho 0.25.0 is currently in development. To try out the most recent snapshot build of 0.25.0, simply add the following snippet to your (parent) pom.xml or settings.xml, and set the property for the Tycho version (e.g. tycho-version) to 0.25.0-SNAPSHOT.
<pluginRepositories>
<pluginRepository>
<id>tycho-snapshots</id>
<url>https://repo.eclipse.org/content/repositories/tycho-snapshots/</url>
</pluginRepository>
</pluginRepositories>