New submission from Jason R. Coombs:
In
https://bitbucket.org/jaraco/backports.functools_lru_cache/issue/1/python-2-attributeerror-int-object-has-no,
a user was confused when he tried to use the lrucache decorator incorrectly,
passing the wrapped function directly to lrucache. Consider:
@lrucache
def expensive(param):
pass
One can even get away with profiling that now decorated function:
for x in range(10000):
expensive(x)
The test will run without error, but it's not doing what the user thinks it's
doing. In the first section, it's creating a decorator, and in the second
section, it's wrapping an int in that decorator, but because the wrapper is
never called, an error is never raised.
I propose adding a simple check that if maxsize is callable, raise a TypeError.
That would prevent unintentional misuse and subtle non-failure with minimal
impact on performance.
----------
components: Library (Lib)
messages: 225202
nosy: jason.coombs, rhettinger
priority: normal
severity: normal
status: open
title: lrucache should reject maxsize as a function
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Python tracker <[email protected]>
<http://bugs.python.org/issue22184>
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