On 6/1/2012 7:40 PM, Temia Eszteri wrote:
Given that len(weakset) is defined (sensibly) as the number of currently
active members, it must count. weakset should really have .__bool__
method that uses any() instead of sum(). That might reduce, but not
necessarily eliminate your problem.
Think it might be worth looking into submitting a patch for the next
minor releases for Python if it turns out to solve the problem?
I think a patch would be worthwhile even if this is not the source of
your problem. If bool is defined as 'if any ...', that should be the code.
I can think of two reasons:
1. You are using multiple threads and another thread does something to
change the size of the set during the iteration. Solution? put a lock
around the if-statement so no other thread can change self.data during
the iteration.
2. Weakset members remove themselves from the set before returning None.
(Just a thought, in case you are not using threads).
In other words, it is possible that weakset.__len__ is buggy. Since you
are sure that 1) is not your problem, that seems more likely now.
If the weak references removing themselves is the case, it seems like
a kind of silly problem - one would imagine they'd wrap the data check
in _IterationGuard in the _weakrefset.py file like they do for calls
to __iter__(). Very strange.
While looking into the weakset code, you might check the tracker for
weakset issues. And also check the test code. I have *no* idea how well
that class has been exercised and tested. Please do submit a patch if
you can if one is needed.
--
Terry Jan Reedy
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