Well, David, I'm convinced this behavior is "logical" and is not some "logic" flaw. My question is more about the fact that it is desirable and was intentionally designed that way,or if on the contrary no one thought it might happen that way and it's not what was wished.

I understand that it might be a problem to link to a global (global a), a variable (h's a) which was declared in a non-global way, but is makes sense to have the presence of "global a" in g, block all possibility for h, to access it's grand parent's a.

In all case, I believe this should at lease be clearly documented in (or in relation with) PEP 3104 to make sure it has been decided that way, or else it will look like a design hole.