FEEDBACK WANTED: Type/class unification

[Duncan Booth]

Guido van Rossum <guido at python.org> wrote in news:cp66cd12yp.fsf at cj20424-
a.reston1.va.home.com:

> Any questions, don't hesitate to ask.

I have a question, or perhaps an observation about the new rules for 
resolving diamond inheritance.

Given a class hierarchy such as:
class A: pass
class B(A):
   def save(self): pass
class C(A):
   def save(self): pass
class D(B, C):
   def foo(self):
       self.save() # Calls B.save

Now, if I add the following code:
class E(B): pass
class F(D, E): pass

f = F()
f.foo()

My understanding of the new rules is that calling f.foo() will result in a 
call to C.save instead of B.save (or in other words, any class that depends 
on the search order for base classes may find this order mysteriously 
changing if it itself is subclassed).

Is my understanding correct? Does it matter? Something similar already 
happens in existing Python programs (define class F(C, D) and you get the 
same effect), but previously you were less likely to encounter diamond 
inheritance.

-- 
Duncan Booth                                             duncan at rcp.co.uk
int month(char *p){return(124864/((p[0]+p[1]-p[2]&0x1f)+1)%12)["\5\x8\3"
"\6\7\xb\1\x9\xa\2\0\4"];} // Who said my code was obscure?