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bpo-40651: Bugfix of the LRU implementation based on OrderedDict in the collections document #20139

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Merged
rhettinger merged 1 commit into from
May 18, 2020
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bpo-40651: Bugfix of the LRU implementation based on OrderedDict in the collections document #20139

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2 changes: 2 additions & 0 deletions Doc/library/collections.rst
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Original file line number Diff line number Diff line change
Expand Up @@ -1161,6 +1161,8 @@ variants of :func:`functools.lru_cache`::
return value

def __setitem__(self, key, value):
if key in self:
self.move_to_end(key)
super().__setitem__(key, value)
if len(self) > self.maxsize:

@remilapeyre remilapeyre May 17, 2020

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I think this part could be replaced by self.popitem(last=False) now.

@qudongfang qudongfang May 17, 2020

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Yes, you are right.
It is cleaner to remove the oldest entry by self.popitem(last=False).

At the same time, It is working correctly.

Do you suggest I update it in this pull request?
Not sure about the conventions here.
Normally we are only supposed to change the code directly related to the issue.

@remilapeyre remilapeyre May 17, 2020

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I don't know, I think popitem() was added in Python3 so this block of code needed to be compatible with Python 2 until this year.

Let's wait for @rhettinger review, I can change it in another PR if he thinks it's needed.

oldest = next(iter(self))
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