public int getNature() {
        if (artifact.getVersion() != null) {
            return artifact.isSnapshot() ? SNAPSHOT : RELEASE;
        }

        VersionRange range = artifact.getVersionRange();
        if (range != null) {
            for (Restriction restriction : range.getRestrictions()) {
                if (isSnapshot(restriction.getLowerBound()) || isSnapshot(restriction.getUpperBound())) {
                    return RELEASE_OR_SNAPSHOT;

        @Override
        public boolean matches(String requirement) {
            try {
                VersionRange range = VersionRange.createFromVersionSpec(requirement);
                if (range.hasRestrictions()) {
                    return range.containsVersion(version);
                } else {
                    return range.getRecommendedVersion().compareTo(version) == 0;
                }

                // Message below is checked for in the MNG-2199 core IT.
                throw new ModelResolverException(
                        String.format(
                                "The requested parent version range '%s' does not specify an upper bound",
                                parent.getVersion()),
                        parent.getGroupId(),
                        parent.getArtifactId(),

                () -> rtInfo.isMavenVersion("[3.0,"),
                "Bad version range wasn't rejected");

        assertThrows(
                IllegalArgumentException.class, () -> rtInfo.isMavenVersion(""), "Bad version range wasn't rejected");

        assertThrows(
                NullPointerException.class, () -> rtInfo.isMavenVersion(null), "Bad version range wasn't rejected");
    }

    @Override
    public Version parseVersion(String version) {
        return modelVersionParser.parseVersion(version);
    }

    @Override
    public VersionRange parseVersionRange(String range) {
        return modelVersionParser.parseVersionRange(range);
    }

    @Override
    public VersionConstraint parseVersionConstraint(String constraint) {
        return modelVersionParser.parseVersionConstraint(constraint);
    }

                    }
                }
            };
        } catch (VersionRangeResolutionException e) {
            throw new VersionRangeResolverException("Unable to resolve version range", e);
        }
    }

        return exceptions == null ? Collections.emptyList() : Collections.unmodifiableList(exceptions);
    }

    // ------------------------------------------------------------------------
    // Version Range Violations
    // ------------------------------------------------------------------------

    public boolean hasVersionRangeViolations() {
        return versionRangeViolations != null;
    }

    /**

                        } else {
                            result = -1;
                        }
                    }
                    if (result == 0) {
                        // We don't consider the version range in the comparison, just the resolved version
                        result = new DefaultArtifactVersion(version)
                                .compareTo(new DefaultArtifactVersion(a.getVersion()));
                    }

- malformed POM
- local repository not writable
- remote repositories not available
- artifact metadata missing
- extension metadata missing
- extension artifact missing
- artifact metadata retrieval problem
- version range violation
- circular dependency
- artifact missing
- artifact retrieval exception
- md5 checksum doesn't match for local artifact, need to redownload this
- POM doesn't exist for a goal that requires one

        // NOTE: Release metadata includes version information about artifacts that have been released, to allow
        // meta-versions like RELEASE and LATEST to resolve, and also to allow retrieval of the range of valid, released
        // artifacts available.
        ArtifactRepositoryPolicy policy = metadata.getPolicy(repository);

        if (!policy.isEnabled()) {
            if (getLogger().isDebugEnabled()) {