We might want to separate between installation and activation, it might be nice to allow a user to activate/deactivate a plugin instead of having to uninstall and reinstall a plugin in particular cases. This would prevent having to reconfigure the plugin again. For example it might be nice to turn off LDAP authentication without having to uninstall the plugin.

public interface LegacySupport {

    /**
     * Sets the currently active session. Some legacy components are basically stateful and their API is missing
     * parameters that would be required to delegate to a stateless component. Saving the session (in a thread-local
     * variable) is our best effort to record any state that is required to enable proper delegation.
     *
     * @param session The currently active session, may be {@code null}.
     */

        // snapshot timestamp, or some other timestamp later encoded into the metadata.
        // TODO this needs to be repeated here so the merging doesn't interfere with the written metadata
        //  - we'd be much better having a pristine input, and an ongoing metadata for merging instead

        Map<ArtifactRepository, Metadata> previousMetadata = new HashMap<>();
        ArtifactRepository selected = null;

        File f2 = getTestFile("src/test/resources/projects/grandchild-check/child/grandchild/pom.xml");

        getProject(f1);

        // it's the building of the grandchild project, having already cached the child project
        // (but not the parent project), which causes the problem.
        getProject(f2);
    }

    @Disabled("Maven 4 does not allow duplicate plugin declarations")
    @Test

        for (ExecutionPlanItem executionPlanItem : planItem) {
            result.add(executionPlanItem.getMojoExecution());
        }
        return result;
    }

    /**
     * Get set of plugins having a goal/mojo used but not marked @threadSafe
     *
     * @return the set of plugins (without info on which goal is concerned)
     */
    public Set<Plugin> getNonThreadSafePlugins() {

     * {@code <groupId>:<artifactId>[:<extension>[:<classifier>]]:<version>}.
     * <p>
     * Shortcut for {@code getService(ArtifactFactory.class).create(...)}.
     *
     * @param coordString the string having "standard" coordinate.
     * @return coordinate used to point to the artifact
     *
     * @see org.apache.maven.api.services.ArtifactCoordinateFactory#create(Session, String)
     */
    @Nonnull

 * all components from this class, and the upfront construction taken care of entirely by the {@link ProjectBuilder}.
 * There is still the issue of having to run the lifecycle in order to find all the compile source roots and resource
 * directories but I hope to take care of this during the Maven 4.0 release (jvz).
 * </p>
 */
public class MavenProject implements Cloneable {

        <field>
          <name>executions</name>
          <version>4.0.0+</version>
          <description>Multiple specifications of a set of goals to execute during the build
            lifecycle, each having (possibly) a different configuration.</description>
          <association>
            <type>PluginExecution</type>
            <multiplicity>*</multiplicity>
          </association>
        </field>

     * Creates a coordinate out of string that is formatted like:
     * {@code <groupId>:<artifactId>[:<extension>[:<classifier>]]:<version>}
     *
     * @param session the session.
     * @param coordinateString the string having "standard" coordinate.
     * @return an {@code ArtifactCoordinate}, never {@code null}
     * @throws IllegalArgumentException if {@code session} is null or invalid
     */
    @Nonnull

  OTOH, all offline-mode checks can probably be run from Wagon-based APIs.

** Maven-SCM

  In all but trivial examples, SCM operations cannot complete without
  having access to the versioning server. Therefore, it is assumed that
  any SCM-related activity will be unavailable when m2 is in offline
  mode.

** Maven-Core