Gush\Validator\MergeWorkflowValidator::presetSemver PHP Method

    protected function presetSemver($source, $target)
    {
        if (0 === preg_match(self::VERSION_REGEX, $source, $sourceMatch) || 0 === preg_match(self::VERSION_REGEX, $target, $targetMatch)) {
            return;
            // cannot validate branches, abstain decision
        }
        if ((int) $sourceMatch['major'] > (int) $targetMatch['major']) {
            throw new MergeWorkflowException([sprintf('Workflow violation: Cannot merge "%s" into "%s".', $source, $target), sprintf('Semver: major version of source "%s" is higher then major version of target "%s".', $source, $target)]);
        }
        if ('x' === $sourceMatch['minor'] || 'x' === $targetMatch['minor']) {
            return true;
            // allow merge
        }
        if ((int) $sourceMatch['minor'] > (int) $targetMatch['minor']) {
            throw new MergeWorkflowException([sprintf('Workflow violation: Cannot merge "%s" into "%s".', $source, $target), sprintf('Semver: minor version of source "%s" is higher then minor version of target "%s".', $source, $target)]);
        }
    }