code: protected boolean gitCheckTagExists(final String tagName) throws MojoFailureException, CommandLineException {
          CommandResult commandResult = executeGitCommandExitCode("show-ref", "--verify", "--quiet",
                  "refs/tags/" + tagName);
          return commandResult.getExitCode() == SUCCESS_EXIT_CODE;
      }
docs: Checks if local tag with given name exists.
  
  @param tagName
  Name of the tag to check.
  @return <code>true</code> if local tag exists, <code>false</code> otherwise.
  @throws MojoFailureException
  @throws CommandLineException