/**
 * A simple memorizing {@link Supplier} of {@link RepositorySystem} instance, that on first call
 * supplies lazily constructed instance, and on each subsequent call same instance. Hence, this instance should be
 * thrown away immediately once repository system was created and there is no need for more instances. If new

 */
package org.apache.maven.execution;

/**
 * Defines events that Maven fires during a build. <strong>Warning:</strong> This interface might be extended in future
 * Maven versions to support further events. Hence it is strongly recommended to derive custom listeners from
 * {@link AbstractExecutionListener} in order to avoid interoperability problems.
 *
 */
public interface ExecutionListener {

                /*
                 * This is purely for backward-compat with 2.x where <extensions> consisting of a single artifact where
                 * loaded into the core and hence available to plugins, in contrast to bigger extensions that were
                 * loaded into a dedicated realm which is invisible to plugins (MNG-2749).
                 */
                publicArtifacts.addAll(artifacts);

     * management entries in their POMs. Maven 3 targeted full backward compatibility with Maven2, hence it ignored
     * dependency management entries in transitive dependency POMs. Maven 4 enables "transitivity" by default, hence
     * unlike Maven2, obeys dependency management entries deep in dependency graph as well.
     * <p>
     * Default: {@code "true"}.
     *

        /*
         * NOTE: This should be considered a quirk to support interop with Maven's legacy ArtifactDeployer which
         * processes one artifact at a time and hence cannot associate the artifacts from the same project to use the
         * same version index. Allowing the caller to pass in metadata from a previous deployment allows to re-establish

    @Nonnull
    Collection<Artifact> getAttachedArtifacts(Project project);

    /**
     * Returns project's all artifacts as immutable collection. The list contains all artifacts, even the attached ones,
     * if any. Hence, the list returned by this method depends on which lifecycle step of the build was it invoked.
     * The head of returned list is result of {@link Project#getArtifacts()} method, so same applies here: the list can have