KConfigIniBackend::isWritable bug

[Nicolas Alvarez]

Hi,

I'm trying to get kdelibs unit tests to run in a clean and headless 
environment (for automated testing). I'm starting an X server, dbus, and 
kdeinit by hand.

Currently kded (started by kdeinit) is failing to start up if I'm running it 
for the first time and there is currently no ~/.kde directory.
Specifically, it's showing a kdialog popup with 'Configuration file 
"/var/lib/buildbot/.kde/share/config/kdedrc" not writable.'. (I don't even 
see the popup because it's on the invisible Xvfb server).

After some code-reading and debugging, I found the cause. kded checks if 
~/.kde/share/config/kdedrc is writable via KConfigIniBackend::isWritable(). 
This function first checks if the file itself is writable using access() 
(well, KStandardDirs::checkAccess). Then there is this code:

// The check might have failed because any of the containing dirs
// did not exist. If the file does not exist, check if the deepest
// existing dir is writable.
if (!QFileInfo(filePath()).exists()) {
    QDir dir = QFileInfo(filePath()).absolutePath();
    while (!dir.exists()) {
        if (!dir.cdUp()) {
            return false;
        }
    }
    return QFileInfo(dir.absolutePath()).isWritable();
}

This code will never succeed for more than one level of directories: 
QDir::cdUp() requires an existing and readable parent directory! So it would 
only work in this case if ~/.kde/share already exists.

What's the cleanest way to rewrite it? dir=dir.filePath("..")?

-- 
Nicolas