Message 166598 - Python tracker

Message166598

Author	sbt
Recipients	alexandre.vassalotti, belopolsky, benjamin.peterson, bpb, brett.cannon, ehuss, facundobatista, fmitha, georg.brandl, gvanrossum, jafo, jaraco, jarpa, kylev, loewis, lukasz.langa, nnorwitz, pitrou, sbt, taleinat, tseaver, vstinner, zbysz, zseil
Date	2012-07-27.19:00:40
SpamBayes Score	-1.0
Marked as misclassified	Yes
Message-id	<1343415641.48.0.990413575644.issue1692335@psf.upfronthosting.co.za>
In-reply-to

Content
> Or you could simply Py_INCREF(args) before the Py_XDECREF... But won't self->args point to a broken object while any callbacks triggered by Py_XDECREF() are run? An alternative would be tmp = self->args; self->args = args; Py_INCREF(self->args); Py_XDECREF(tmp); As far as I can see the idiom Py_?DECREF(self->...) is rarely safe outside of a deallocator unless you are sure the pointed to object has a "safe" type (or you are sure the refcount cannot fall to zero).

Content

> Or you could simply Py_INCREF(args) before the Py_XDECREF...

But won't self->args point to a broken object while any callbacks triggered by Py_XDECREF() are run?

An alternative would be

    tmp = self->args;
    self->args = args;
    Py_INCREF(self->args);
    Py_XDECREF(tmp);

As far as I can see the idiom Py_?DECREF(self->...) is rarely safe outside of a deallocator unless you are sure the pointed to object has a "safe" type (or you are sure the refcount cannot fall to zero).

History
Date	User	Action	Args
2012-07-27 19:00:41	sbt	set	recipients: + sbt, gvanrossum, loewis, nnorwitz, brett.cannon, georg.brandl, facundobatista, jafo, ehuss, tseaver, jaraco, belopolsky, zseil, fmitha, pitrou, vstinner, taleinat, alexandre.vassalotti, benjamin.peterson, jarpa, bpb, zbysz, kylev, lukasz.langa
2012-07-27 19:00:41	sbt	set	messageid: <1343415641.48.0.990413575644.issue1692335@psf.upfronthosting.co.za>
2012-07-27 19:00:40	sbt	link	issue1692335 messages
2012-07-27 19:00:40	sbt	create