// This is often an artifact like a POM that is taken from disk and we already have hold of the
        // file reference. But this may be a Maven Plugin that we need to resolve from a remote repository
        // as well as its dependencies.

        if (request.isResolveRoot() /* && rootArtifact.getFile() == null */) {
            try {
                resolve(rootArtifact, request.getRemoteRepositories(), session);

     * This method will record extra information as well, like plugin occurrence or declaration location.
     */
    void reportPluginValidationIssue(
            IssueLocality locality, MavenSession mavenSession, MojoDescriptor mojoDescriptor, String issue);

    /**
     * Reports plugin Mojo issues applicable to the Mojo itself.
     * <p>
     * This method will record extra information as well, like plugin occurrence or declaration location.

import org.apache.maven.model.version.ModelVersionParser;

import static org.apache.maven.internal.impl.Utils.nonNull;

/**
 * A wrapper class around a resolver version that works as model version parser as well.
 */
@Named
@Singleton
public class DefaultVersionParser implements VersionParser {
    private final ModelVersionParser modelVersionParser;

    @Inject

 * under the License.
 */
package org.apache.maven.artifact.repository.metadata.io;

import java.io.IOException;

/**
 * Signals a failure to parse the metadata due to invalid syntax (e.g. non well formed XML or unknown elements).
 *
 */
public class MetadataParseException extends IOException {

    /**
     * The one-based index of the line containing the error.
     */
    private final int lineNumber;

    /**
     * Creates a request for the specified plugin by copying settings from the specified build session. If the session
     * has a current project, its plugin repositories will be used as well.
     *
     * @param plugin The plugin for which to resolve a version, must not be {@code null}.
     * @param session The Maven session to use, must not be {@code null}.
     */

- test projects for each of these
- how to categorize the problems so that the id of the problem can be match to a page with descriptive help and the test
  project
- nice little sample projects that could be run in the core as well as integration tests

All Possible Errors
- invalid lifecycle phase (maybe same as bad CLI param, though you were talking about embedder too)
- <module> specified is not found
- malformed settings
- malformed POM

 * is thread safe.
 * <p>
 * Important: Given the instance of supplier memorizes the supplier {@link RepositorySystem} instance it supplies,
 * their lifecycle is shared as well: once supplied repository system is shut-down, this instance becomes closed as
 * well. Any subsequent {@code getXXX} method invocation attempt will fail with {@link IllegalStateException}.
 */
public class RepositorySystemSupplier implements Supplier<RepositorySystem> {

                }
            }
        }

        /*
         * MNG-4312: We neither have reserved all of the above magic expressions nor is their set fixed/well-known (it
         * gets occasionally extended by newer Maven versions). This imposes the risk for existing plugins to
         * unintentionally use such a magic expression for an ordinary property. So here we check whether we

abstract class, which will ensure that the Matcher API can grow to support new features and remain compatible with all Matcher implementations. For easy access to common Matcher implementations, use the static factory methods in CoreMatchers. N.B. Well designed matchers should be immutable. See Also: CoreMatchers, BaseMatcher Method Summary void _dont_implement_Matcher___instead_extend_BaseMatcher_() Deprecated. to make void describeMismatch(java.lang.Object item, Description mismatchDescription)...

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 the following conditions:

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