[Zope-dev] Re: Zope 2.7 and objects turning into None
On Fri, 20 Feb 2004 09:47:47 +1100 Richard Jones [EMAIL PROTECTED] wrote: On Friday 20 February 2004 05:52, Dieter Maurer wrote: We have a report for Zope 2.7 about an object magically turning into None (1 or 2 weeks ago). Sorry, I haven't been following this thread, but I will note that I've seen (repeatably) in my test Zope environment this behaviour. This is probably unrelated though... For me, the situation comes about when I am loading up my fresh (ie. clean ZODB) test Zope with a thousand users. While the load script is running (it runs on the command-line and goes TTW using urllib to register the users) if I access a page which summarises all users, I *sometimes* get None for some of the users. The page uses a Catalog to find basic user info, and sometimes uses getObject() to find the real user object. The getObject() appears to return None sometimes. This is a guess, but perhaps the Catalog is masking some other low-level error and returning None instead? I'll see if that seems possible from the code. -Casey ___ Zope-Dev maillist - [EMAIL PROTECTED] http://mail.zope.org/mailman/listinfo/zope-dev ** No cross posts or HTML encoding! ** (Related lists - http://mail.zope.org/mailman/listinfo/zope-announce http://mail.zope.org/mailman/listinfo/zope )
[Zope-dev] Re: Zope 2.8
Christian Theune wrote: - Does a proposal for the post-traverse-hook have a chance for 2.8? (The code is here completely working on 2.7, I only need to write tests.) Please, write tests and merge to the HEAD. I see no reason why this shouldn't go into 2.8. Cheers, Evan @ 4-am ___ Zope-Dev maillist - [EMAIL PROTECTED] http://mail.zope.org/mailman/listinfo/zope-dev ** No cross posts or HTML encoding! ** (Related lists - http://mail.zope.org/mailman/listinfo/zope-announce http://mail.zope.org/mailman/listinfo/zope )
Re: [Zope-dev] Core Dump (Zope 2.7, Python 2.3.3, FreeBSD 4.5)
Dieter Maurer wrote at 2004-2-19 19:52 +0100: We have a report for Zope 2.7 about an object magically turning into None (1 or 2 weeks ago). A similar problem was discovered recently by a colleague. I started analysing it today. It turned out that objects are non-deterministically converted into None. I have seen such behaviour in the past (with an old Python version). Later, it turned out to be a memory corruption problem in this Python version. Memory corruption can also cause death with a core dump. It is well possible that our problem is caused by my Zope modifications or other (third party) C level extensions. But, there might also be some lingering problem in Python2.3.3/Zope2.7. After having looked at the Python code, I recognize the extreme low likelyhood that a memory corruption manifests itself in objects becoming None. I was able to explain most (if not all) of our problems from harmless causes: * I had a bare return in a function that should return a value -- protected by a condition that is true only under very special (history dependent) circumstances. This explains the apparently non-deterministic apparent transition to None. In fact, no object transitioned to None and the behaviour was completely deterministic. * Another family of incidents where apparently constant objects became None was explained by the well known refresh property to bind the variables in a flushed module to None. * A third report is not yet explained but I am confident that it, too, will find an explanation without a memory corruption assumption. -- Dieter ___ Zope-Dev maillist - [EMAIL PROTECTED] http://mail.zope.org/mailman/listinfo/zope-dev ** No cross posts or HTML encoding! ** (Related lists - http://mail.zope.org/mailman/listinfo/zope-announce http://mail.zope.org/mailman/listinfo/zope )
Re: [Zope-dev] Re: Zope 2.7 and objects turning into None
Casey Duncan wrote at 2004-2-20 10:53 -0500: ... This is a guess, but perhaps the Catalog is masking some other low-level error and returning None instead? I'll see if that seems possible from the code. Some time ago, I found out that OFS.Traversable.Traversable.unrestrictedTraverse catched ConflictError and returned default if a default has been specified. I filed a bug report but I am not sure whether this was fixed (it is fixed in our Zope version, of course). -- Dieter ___ Zope-Dev maillist - [EMAIL PROTECTED] http://mail.zope.org/mailman/listinfo/zope-dev ** No cross posts or HTML encoding! ** (Related lists - http://mail.zope.org/mailman/listinfo/zope-announce http://mail.zope.org/mailman/listinfo/zope )
