for (FieldConfig srcFieldConfig : srcGroupConfig.getFieldConfigList()) {
mergeField((FieldConfigImpl) srcFieldConfig, checkDuplicate);
}
} else {
// merge/import single field
FieldConfig srcFieldConfig = srcGroupConfig.getFieldConfig(fieldName);
assertNotNull(srcFieldConfig, "Field \"%s.%s\" not found", srcGroupConfig.getName(), fieldName);
mergeField((FieldConfigImpl) srcFieldConfig, checkDuplicate);
}
}