Issue with optional attributes in simple tags

[gcharita]

There is an issue on mapping simple tags (a tag with just inner text) that have optional attributes.

When there is at least one attribute present, everything work fine:

<root>
    <tag optionalAttribute="attribute value">innetText</testString>
</root>

But when there is no attribute present:

<root>
    <tag>innetText</testString>
</root>

mapping using the same model produces nil:

class Root: XMLMappable {
    var nodeName: String!
    
    var tag: Tag?
    
    required init?(map: XMLMap) {}
    
    func mapping(map: XMLMap) {
        tag <- map["tag"]
    }
}

class Tag: XMLMappable {
    var nodeName: String!
    
    var optionalAttribute: String?
    var text: String?
    
    required init?(map: XMLMap) {}
    
    func mapping(map: XMLMap) {
        optionalAttribute <- map.attributes["optionalAttribute"]
        text <- map.innerText
    }
}