Error when a class inherits from a class with same name

[epeios-q37]

Hello Pierre,

Following code does not work properly with Brython:

class A:
  pass

class B:
  class A(A):
    pass

print("Success!")     

With regular Python:

Success!

With Brython:

Traceback (most recent call last):
  File <string>, line 4, in <module>
  File <string>, line 5, in B
AttributeError: Javascript object 'undefined' has no attribute

Thanks!

[jsbueno]

Let's agree that this is some very fringe Python code. :-)

Although, yes, in Python rules, this works, it wouldn't work in a namespace inside a function, for example - the "A" would EITHER be bound ot to the global namespace or to the local namespace. For namespaces in class bodies, we have different rules, but more due to historic reasons than for anything that makes sense.

That said, I believe there is no specification saying this should be "undefined behavior" - so you are right that
Brython should (somehow) behave the same as Python for this.

In [13]: class A: pass

In [14]: class B:
   ...:     print(A, locals().get("A", "no A in locals"))
   ...:     class A(A): pass
   ...:     print(A , locals().get("A", "no A in locals"))
   ...:  
<class '__main__.A'> no A in locals
<class '__main__.B.A'> <class '__main__.B.A'>

(but inside a function, since "A" would be bound to a local variable later in the
local function namespace, it is threated as a local variable from the start, and
the code above wouldn't work)

In [15]: class A: pass

In [16]: def factory():
   ...:     class A(A): pass
   ...:     return A
   ...:  
       
       
In [17]: A0 = factory()
---------------------------------------------------------------------------
UnboundLocalError                         Traceback (most recent call last)
Cell In[17], line 1
----> 1 A0 = factory()

Cell In[16], line 2, in factory()
     1 def factory():
----> 2     class A(A): pass
     3     return A