The new compiled Qt Creator (shadow build under latest Qt from git and manually set paths) throws an unknown error while attempting to write XML config sequences into:

~/.config/QtProject/qtcreator/<filename>.xml

Unfortunately, I can not find root of this error because it reproduces whether I run Qt Creator under GDB debugger or not, from scratch of from root. Any attempts I tried were all unsuccessful. Also I tried to recompile all Qt suite from the clear source tree (successfully built) and then the error reproduced. Any XML writing operations produce no output files here. Console throws two messages like:

Empty filename passed to function