Folder History is not working anymore.
BUG: 379177
Commit 840d1c40bc906b0961418c8b738aef3971e7dce2 broke it.
QStandardPaths::locate(QStandardPaths::AppLocalDataLocation, "recentfolders/")
always returns an empty string "" when either the recentfolders folder or the ~/.local/share/gwenview folder don't exist.
See: http://doc.qt.io/qt-5/qstandardpaths.html#locate
If no such file or directory can be found, an empty string is returned
KStandardDirs::locateLocal behaves differently (from the api doc)
No check is made if the specified filename actually exists. Missing directories are created.
As we don't want to switch back to KStandardDirs I came up with a working patch using QStandardPaths::writableLocation (see attachment) as
Note: The storage location returned can be a directory that does not exist; i.e., it may need to be created by the system or the user.
(from : http://doc.qt.io/qt-5/qstandardpaths.html#writableLocation )