private String getExecutionId(Plugin plugin, String goal) {
        Set<String> existingIds = new HashSet<>();
        for (PluginExecution execution : plugin.getExecutions()) {
            existingIds.add(execution.getId());
        }

        String base = "default-" + goal;
        String id = base;

        for (int index = 1; existingIds.contains(id); index++) {
            id = base + '-' + index;
        }

    private static String getExecutionId(Plugin plugin, String goal) {
        Set<String> existingIds = plugin != null
                ? plugin.getExecutions().stream().map(PluginExecution::getId).collect(Collectors.toSet())
                : Set.of();
        String base = "default-" + goal;
        String id = base;
        for (int index = 1; existingIds.contains(id); index++) {
            id = base + '-' + index;
        }