New submission from Seth Bromberger:
ipaddress.ip_address instances should be flyweight. There's really no reason to
make them mutable:
>>> a = ipaddress.ip_address("10.1.2.3")
>>> b = ipaddress.ip_address("10.1.2.3")
>>> id(a)
14006653377
Seth Bromberger added the comment:
Confirmed on 3.4.0; likely exists in previous versions as well.
--
versions: +Python 3.4 -Python 3.6
___
Python tracker
<http://bugs.python.org/issue23
Seth Bromberger added the comment:
>What is your proposal? WeakValueDictionary mapping raw bytes object to single
>instance of ipaddress that is queried from ipaddress's __new__? No built-in
>has quite that extensive a level of caching and aggressive deduplication to my
>
Seth Bromberger added the comment:
1) However:
>>> b = ipaddress.IPv4Address('1.2.3.4')
>>> a = ipaddress.IPv4Address('1.2.3.4')
>>> id(a)
4428380928
>>> id(b)
4428381768
>>> a == b
True
>>> b._ip += 6
>>>
Seth Bromberger added the comment:
>The opposite argument is that it may be better left up to the application that
>has to handle lots of ips to do the caching according to what it knows to be
>an optimum pattern.
I'd agree with you wholeheartedly if ipaddress wasn't part
Seth Bromberger added the comment:
As a test, I tried the following (taken mostly from
http://codesnipers.com/?q=python-flyweights):
class Foo(object):
_Foo = weakref.WeakValueDictionary()
def __new__(cls, addr):
obj = Foo._Foo.get(addr, None)
if obj is None
Seth Bromberger added the comment:
Sorry for the additional followup, but I re-ran the test with approximately
real-world parameters. In this second test, I created 10 million Foo()
instances with random values from 1-2000 (using random.randint). This
corresponds to "2000 hosts generati
Seth Bromberger added the comment:
>I'm just pointing out that if he thinks 56 bytes per object is too large, he's
>going to be disappointed with what Python has to offer. General purpose
>user-defined Python objects don't optimize for low memory usage, and even
>
