[Python-bugs-list] [ python-Bugs-484950 ] docs suggest no cyclic garbage collectio

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Bugs item #484950, was opened at 2001-11-23 10:50
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Category: Documentation
Group: None
>Status: Open
Resolution: None
Priority: 5
Submitted By: Zooko Ozoko (zooko)
Assigned to: Fred L. Drake, Jr. (fdrake)
Summary: docs suggest no cyclic garbage collectio

Initial Comment:
http://python.sourceforge.net/devel-docs/ext/refcounts.html

Section 1.10 is a bit out of date -- it would lead some
readers to believe that Python doesn't collect cyclical
garbage.


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>Comment By: Zooko Ozoko (zooko)
Date: 2001-11-28 05:52

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The last paragraph contrasts Python's chosen strategy,
reference counting, with 
the more standard "automatic garbage collection".  Most
readers will know that 
reference counting suffers from the problem of not
collecting cyclical garbage 
where garbage collection does not.  Thus, seeing the two
contrasted like this, 
and the reason for Python's lack of garbage collection being
given as "there 
isn't a good one available", they may infer that Python
doesn't collect cyclical 
garbage.

I suggest to strike the last paragraph and replace it with
something like:

"""
The strategy of reference counting traditionally suffers
from the problem that 
the interpreter doesn't collect "cyclical garbage". 
Cyclical garbage is a set 
of objects which have been unlinked so that they are
unreachable, but they 
contain references to each other so that each object's
counter is non-zero.

As of version 2.0, Python includes a "garbage cycle
collector" which recovers the 
memory from cyclical garbage as well.  (Note that there is
an important caveat 
that the cycle collector does not free objects which contain
`__del__' methods, 
although the normal non-cyclic reference counting system
will free those 
objects.  Please see XXX for more information.)
"""

Regards,

Zooko


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Comment By: Fred L. Drake, Jr. (fdrake)
Date: 2001-11-27 22:28

Message:
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Oops, that was *pending*, not closed!

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Comment By: Fred L. Drake, Jr. (fdrake)
Date: 2001-11-27 22:19

Message:
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user_id=3066

I must be missing something; what makes you think this
implies cyclical garbage isn't collected?

Marked pending awaiting further information.

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