code: public void execute( EnforcerRuleHelper helper )
          throws EnforcerRuleException
      {
          boolean callSuper;
          MavenProject project = null;
          if ( onlyWhenRelease )
          {
              // get the project
              project = getProject( helper );
  
              // only call super if this project is a release
              callSuper = !project.getArtifact().isSnapshot();
          }
          else
          {
              callSuper = true;
          }
          if ( callSuper )
          {
              super.execute( helper );
              if ( failWhenParentIsSnapshot )
              {
                  if ( project == null )
                  {
                      project = getProject( helper );
                  }
                  Artifact parentArtifact = project.getParentArtifact();
                  if ( parentArtifact != null && parentArtifact.isSnapshot() )
                  {
                      throw new EnforcerRuleException( "Parent Cannot be a snapshot: " + parentArtifact.getId() );
                  }
              }
          }
      }
docs: Override parent to allow optional ignore of this rule.
  
  @param helper the enforcerRuleHelper
  @throws EnforcerRuleException when an exception occurs