[docs] [issue24020] threading.local() must be run at module level (doc improvement)
Eric Snow
report at bugs.python.org
Tue Apr 21 21:11:41 CEST 2015
Eric Snow added the comment:
FYI, I've used thread-local namespaces with success in several different ways and none of them involved binding the thread-local namespace to global scope. I don't think anything needs to be fixed here.
The SO answer is misleading and perhaps even wrong. The problem it describes is about sharing the thread-local NS *between function calls*. Persisting state between function calls is not a new or mysterious problem, nor unique to thread-local namespaces. In the example they give, rather than a global they could have put it into a default arg or into a class:
def hi(threadlocal=threading.local()):
...
class Hi:
threadlocal = threading.local()
def __call__(self):
... # change threadlocal to self.threadlocal
hi = Hi()
This is simply a consequence of Python's normal scoping rules (should be unsurprising) and the fact that threading.local is a class (new instance per call) rather than a function (with the assumption of a singleton namespace per thread).
At most the docs could be a little more clear that threading.local() produces a new namespace each time. However, I don't think even that is necessary and suggest closing this as won't fix.
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nosy: +eric.snow
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<http://bugs.python.org/issue24020>
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