Why QXmlQuery seem to add a ` \n` to results? (and how to solve it?)

Question

Writing a little code to extract some values from an XML, the result of the XPath seem to add \n after the content.

#include <QCoreApplication>
#include <QXmlQuery>
#include <QString>
#include <QDebug>

auto main(int argn, char* argc[])->int
{
    QCoreApplication app(argn, argc);

    QString replyContent="<Root isOk='ok'/>";

    QXmlQuery query;
    query.setFocus(replyContent);
    query.setQuery("string(//@isOk)");

    // Attribute seem to add \n
    QString queryResult;    
    if (query.evaluateTo(&queryResult))
    {
        qDebug() << queryResult;              // Where this \n come from?
        qDebug() << queryResult.size();       // Why 3? shouldn't be 2?
    }
}

Expected result:

"ok"
2

Given result:

"ok\n"
3

This obviously has some side effects which I would like to avoid.

Why is this \n added? And how to solve it?

Answer 1

I think that this is introduced by the QXmlFormatter that is used when serialising the results to a QString; I suspect that QXmlFormatter::endDocument writes a newline.

One workaround would be to output to a string list instead, then pick the first element:

QStringList results;
if (query.evaluateTo(&results))
{
    const QString& queryResult = results.first();
    qDebug() << queryResult;
    qDebug() << queryResult.size();
}

You might choose to join() the results instead, if you need them all.