[Python-Dev] 2.4.4: backport classobject.c HAVE_WEAKREFS?

[Armin Rigo]

Hi Raymond,

On Fri, Oct 06, 2006 at 08:48:15AM -0700, Raymond Hettinger wrote:
> No need to backport.  Py_TPFLAGS_DEFAULT implies
> Py_TPFLAGS_HAVE_WEAKREFS.
> 
> 
> The change was for clarity -- most things that have the weakref slots
> filled-in will also make the flag explicit -- that makes it easier on
> the brain when verifying code that checks the weakref flag.

I don't understand why you added this flag here; there are many other
flags with a meaning very similar to Py_TPFLAGS_HAVE_WEAKREFS, which are
also implied by Py_TPFLAGS_DEFAULT.  Also, *all* other types in a
CPython build use Py_TPFLAGS_DEFAULT as well, so have
Py_TPFLAGS_HAVE_WEAKREFS set.  Why would explicitly spelling just this
flag, on just this type, help make the overall code clearer?  It seems
to only further confuse the matter -- the slightly obscure bit that
requires some getting used to is that all these flags don't really mean
"I have such and such feature" but just "I could have such and such
feature, if the corresponding tp_xxx field were set".


A bientot,

Armin