pycairo is not the upstream package for this bug, pygtk is (and pycairo is upstream for pygtk).
cr.reset_clip() is calling gtk.gdk.CairoContext.reset_clip.
This is a pygtk function not a pycairo function.
Philippe Gauthier has already successfully diagnosed the problem, on BOTH the bug reports you quote, as being pygtk and not pycairo. Why do you ignore his advice?.
pycairo is not the upstream package for this bug, pygtk is (and pycairo is upstream for pygtk).
cr.reset_clip() is calling gtk.gdk. CairoContext. reset_clip.
This is a pygtk function not a pycairo function.
Philippe Gauthier has already successfully diagnosed the problem, on BOTH the bug reports you quote, as being pygtk and not pycairo. Why do you ignore his advice?.
I suggest you open a bug report for pygtk.