{
        final LinkedList<ScopeState> stack = values.get();
        if ( stack == null || stack.isEmpty() )
        {
            throw new IllegalStateException();
        }
        stack.removeFirst();
        if ( stack.isEmpty() )
        {
            values.remove();
        }
    }

    public <T> void seed( Class<T> clazz, Provider<T> value )
    {
        getScopeState().seeded.put( Key.get( clazz ), value );
    }

    public <T> void seed( Class<T> clazz, final T value )
    {
        getScopeState().seeded.put( Key.get( clazz ), Providers.of( value ) );
    }

    public <T> Provider<T> scope( final Key<T> key, final Provider<T> unscoped )
    {
        return new Provider<T>()
        {
            @SuppressWarnings( "unchecked" )
            public T get()
            {
                LinkedList<ScopeState> stack = values.get();
                if ( stack == null || stack.isEmpty() )
                {
                    throw new OutOfScopeException( "Cannot access " + key + " outside of a scoping block" );
                }

                ScopeState state = stack.getFirst();

                Provider<?> seeded = state.seeded.get( key );

                if ( seeded != null )
                {
                    return (T) seeded.get();
                }

                T provided = (T) state.provided.get( key );
                if ( provided == null && unscoped != null )
                {
                    provided = unscoped.get();
                    state.provided.put( key, provided );
                }

                return provided;
            }
        };
    }

    @SuppressWarnings( { "unchecked" } )
    public static <T> Provider<T> seededKeyProvider()
    {
        return (Provider<T>) SEEDED_KEY_PROVIDER;
    }

    private Artifact createArtifact( String groupId, String artifactId, VersionRange versionRange, String type,
                                     String classifier, String scope, String inheritedScope, boolean optional )
    {
        String desiredScope = Artifact.SCOPE_RUNTIME;

        if ( inheritedScope == null )
        {
            desiredScope = scope;
        }
        else if ( Artifact.SCOPE_TEST.equals( scope ) || Artifact.SCOPE_PROVIDED.equals( scope ) )
        {
            return null;
        }
        else if ( Artifact.SCOPE_COMPILE.equals( scope ) && Artifact.SCOPE_COMPILE.equals( inheritedScope ) )
        {
            // added to retain compile artifactScope. Remove if you want compile inherited as runtime
            desiredScope = Artifact.SCOPE_COMPILE;
        }

        if ( Artifact.SCOPE_TEST.equals( inheritedScope ) )
        {
            desiredScope = Artifact.SCOPE_TEST;
        }

        if ( Artifact.SCOPE_PROVIDED.equals( inheritedScope ) )
        {
            desiredScope = Artifact.SCOPE_PROVIDED;
        }

        if ( Artifact.SCOPE_SYSTEM.equals( scope ) )
        {
            // system scopes come through unchanged...
            desiredScope = Artifact.SCOPE_SYSTEM;
        }

        ArtifactHandler handler = artifactHandlerManager.getArtifactHandler( type );

        return new DefaultArtifact( groupId, artifactId, versionRange, desiredScope, type, classifier, handler,
                                    optional );
    }
}

    {
        MavenSession session = legacySupport.getSession();

        PluginDescriptor pluginDescriptor;
        try
        {
            pluginDescriptor =
                pluginManager.getPluginDescriptor( plugin, session.getCurrentProject().getRemotePluginRepositories(),
                                                   session.getRepositorySession() );

            pluginManager.setupPluginRealm( pluginDescriptor, session, null, null, null );
        }
        catch ( Exception e )
        {
            throw new PluginManagerException( plugin, e.getMessage(), e );
        }

        ClassLoader oldClassLoader = Thread.currentThread().getContextClassLoader();
        try
        {
            Thread.currentThread().setContextClassLoader( pluginDescriptor.getClassRealm() );

            return container.lookup( role, roleHint );

    }

    private static String format( LocalRepository localRepository, List<RemoteRepository> remoteRepositories )
    {
        String repos = "[";

        if ( localRepository != null )
        {
            repos += localRepository.getId() + " (" + localRepository.getBasedir() + ")";
        }

        if ( remoteRepositories != null && !remoteRepositories.isEmpty() )
        {
            for ( RemoteRepository repository : remoteRepositories )
            {
                repos += ", ";

                if ( repository != null )
                {
                    repos += repository.getId() + " (" + repository.getUrl() + ")";
                }
            }
        }

        repos += "]";

        return repos;
    }

}