[Zope-dev] More Transience weirdness in 2.7.1b1

[Tim Peters]

[Steve Jibson]
> It seems that there may still be some strangeness with Transience. We're
> running Zope-2.7.1b1 (Python 2.3.3, Fedora Core 1)

...
> So, I hook-up to the ZMI and click on *temp_folder*, then click on    
> *session_data (Session Data Container)* and I get the following error:
>
>    Traceback (innermost last):
>      Module ZPublisher.Publish, line 101, in publish
>      Module ZPublisher.mapply, line 88, in mapply
>      Module ZPublisher.Publish, line 39, in call_object
>      Module App.special_dtml, line 62, in __call__
>      Module DocumentTemplate.DT_String, line 474, in __call__
>      Module Products.Transience.Transience, line 709, in nudge
>      Module Products.Transience.Transience, line 555, in _gc
>    RuntimeError: the bucket being iterated changed size

FWIW, the RuntimeError is raised in the bowels of the BTree implementation,
and can occur if someone performs a size-changing mutation on a BTree while
iterating over the BTree.  A discussion, and concrete example, can be found
in the "Iteration and Mutation" section (5.3.2) here:

    http://zope.org/Wikis/ZODB/FrontPage/guide/node6.html

ChrisM will be familiar with the cause <wink>.