[Python-Dev] PyObject_GC_UnTrack() no longer reliable in 2.7?

"Martin v. Löwis" martin at v.loewis.de
Sun Sep 26 18:55:58 CEST 2010

Am 26.09.2010 12:54, schrieb Nick Coghlan:
> On Sat, Sep 25, 2010 at 9:20 AM, Tim Peters <tim.peters at gmail.com> wrote:
> [MvL]
>>> I think it would be possible to have two versions of
>>> _PyGC_REFS_UNTRACKED, one being, say, -5.
>>> _PyGC_REFS_UNTRACKED_AND_KEEP_IT_THAT_WAY would be what you get
>>> when you call PyObject_GC_UnTrack; the code to do automatic
>>> tracking/untracking based on contents would use some other
>>> new API (which would be non-public in 2.7.x).
>> Looks like a promising idea!  gcmodule.c's IS_TRACKED macro would have
>> to change to check both states, and likewise the debug assert in
>> visit_reachable().
> Given the intent is to restore the 2.6 state, perhaps it is the
> "UNTRACK_ALLOW_RETRACK" optimisation that should get the new special
> value? Other than that, MvL's suggestion looks like a good idea.

It would work either way, of course.


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