[Python-checkins] CVS: python/dist/src/Objects descrobject.c,1.1.2.13,1.1.2.14

[Tim Peters]

[Guido]
> ...
> Note that the presence of a __set__ method doesn't mean that the
> attribute can actually be assigned to: this is also used to make
> attributes deliberately read-only, by making the __set__ method always
> raise an exception.  (Q: should it raise AttributeError or TypeError?
> Traditionally, this has raised TypeError!)

I always thought AttributeError was to an instance dict as NameError is to a
global dict:  "ain't got no such name".  So I vote for TypeError.
AttributeError is more appropriate when trying to fetch an attribute that
doesn't exist.

A twist:  suppose Spam.i can only take on string values.  Should

    Spam.i = 42

then raise TypeError or AttributeError?  Obviously TypeError.  Trying to do

    Spam.readonly = 12

is the same thing, in that Spam.readonly can only take on no new values
<wink>.