QFileInfo::fileName should return an empty QString on an empty file name.

While constructing a QFileInfo with QFileInfo::QFileInfo(const QDir &dir, const QString &file) with a default constructed QDir and QString (both empty), calling QFileInfo::fileName() returns "." instead of an empty QString. Here's an example:

// provided variables that turned out to be empty
QDir emptyDir;
QString emptyFile;

QFileInfo fileInfo(emptyDir, emptyFile);

if(fileInfo.fileName().isEmpty()) { // this check failes, fileName is actually "."
    // do something
}

QDir("") becoming "." is sane and documented:

https://doc.qt.io/qt-6/qdir.html#QDir-1
If path is empty the program's working directory, ("."), is used

But I would think QFileInfo(..., file).fileName() == file should be true