if (id == null || id.isEmpty()) {
                throw new InvalidRepositoryException("Repository identifier missing", "");
            }

            String url = repo.getUrl();

            if (url == null || url.isEmpty()) {
                throw new InvalidRepositoryException("URL missing for repository " + id, id);
            }

        This is the file specification used to activate a profile. The missing value will be the location
        of a file that needs to exist, and if it doesn't the profile must run.  On the other hand exists will test
        for the existence of the file and if it is there will run the profile.
      </description>
      <fields>
        <field>
          <name>missing</name>
          <version>1.0.0+</version>

    }

    @Test
    void testBuildStubModelForMissingRemotePom() throws Exception {
        Artifact pom = repositorySystem.createProjectArtifact("org.apache.maven.its", "missing", "0.1");
        MavenProject project = getProject(pom, true);

        assertNotNull(project.getArtifactId());

        assertNotNull(project.getRemoteArtifactRepositories());

                new PluginParameterException(mojoDescriptor, Collections.singletonList(parameter));

        assertEquals(
                "One or more required plugin parameters are invalid/missing for 'goalPrefix:goal'" + LS
                        + LS + "[0] Inside the definition for plugin 'artifactId', specify the following:"
                        + LS
                        + LS + "<configuration>"

                    missingDescriptor(session, trace, a, (Exception) e.getCause());
                    if ((getPolicy(session, a, request) & ArtifactDescriptorPolicy.IGNORE_MISSING) != 0) {
                        return null;
                    }
                }
                result.addException(e);
                throw new ArtifactDescriptorException(result);
            }

 *
 * @since 3.0
 */
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.
     *

                    result.setArtifact(artifact);
                } catch (FileNotFoundException | URISyntaxException e) {
                    throw new IllegalStateException("Missing test POM for " + artifact, e);
                }
            } else {
                result.addException(new ArtifactNotFoundException(artifact, (RemoteRepository) null));

    MavenExecutionResult setDependencyResolutionResult(DependencyResolutionResult result);

    DependencyResolutionResult getDependencyResolutionResult();

    // for each exception
    // - knowing what artifacts are missing
    // - project building exception
    // - invalid project model exception: list of markers
    // - xmlpull parser exception
    List<Throwable> getExceptions();

    MavenExecutionResult addException(Throwable e);

                        // 1 extra '/' to remove
                        url.setLength(url.length() - 1);
                    }
                } else if (!initialUrlEndsWithSlash) {
                    // add missing '/' between url and path
                    url.append('/');
                }

                url.append(path);

                // ensure resulting url ends with slash if initial url was

            selectedProjects.addAll(
                    projectSelector.getOptionalProjectsBySelectors(request, allSortedProjects, optionalSelectors));

            // it can be empty when an optional project is missing from the reactor, fallback to returning all projects
            if (!selectedProjects.isEmpty()) {
                result = new ArrayList<>(selectedProjects);