I have clone the source code and "git checkout 3.11.0 -b my_branch".
When I enter /meld/bin and run meld, it says that: Cannot import: GTK+ cannot import name PyGIDeprecationWarning
The only reference to that error I can find suggests that you may need to mess with your PYTHONPATH because of import order issue. This seems... weird, but possible.
My only other guess would be that you may not have the gobject-introspection repository installed.
