One function

TTLCache in tkem/cachetools

The author described this change as “Fix #221: Change exact time of expiration in TTLCache.”. It counts as a record because the check below fails on the code as it stood at 4d11ef92d and passes on 91aa4c63f, with nothing else changed between the two runs.

Projecttkem/cachetools

Fix saved2021-12-18

Sharing licenceMIT · LICENSE

Change size+6 −6

What the code was meant to do, written into the code itself as a docstring

LRU Cache implementation with per-item time-to-live (TTL) value.

The change

15	15		except KeyError:
16	16		return False
17	17		else:
18		-	return not (link.expire < self.__timer())
	18	+	return self.__timer() < link.expire
19	19
20	20		def __getitem__(self, key, cache_getitem=Cache.__getitem__):
21	21		try:
⋯
23	23		except KeyError:
24	24		expired = False
25	25		else:
26		-	expired = link.expire < self.__timer()
	26	+	expired = not (self.__timer() < link.expire)
27	27		if expired:
28	28		return self.__missing__(key)
29	29		else:
⋯
48	48		cache_delitem(self, key)
49	49		link = self.__links.pop(key)
50	50		link.unlink()
51		-	if link.expire < self.__timer():
	51	+	if not (self.__timer() < link.expire):
52	52		raise KeyError(key)
53	53
54	54		def __iter__(self):
⋯
57	57		while curr is not root:
58	58		# "freeze" time for iterator access
59	59		with self.__timer as time:
60		-	if not (curr.expire < time):
	60	+	if time < curr.expire:
61	61		yield curr.key
62	62		curr = curr.next
63	63
⋯
66	66		curr = root.next
67	67		time = self.__timer()
68	68		count = len(self.__links)
69		-	while curr is not root and curr.expire < time:
	69	+	while curr is not root and not (time < curr.expire):
70	70		count -= 1
71	71		curr = curr.next
72	72		return count
⋯
110	110		curr = root.next
111	111		links = self.__links
112	112		cache_delitem = Cache.__delitem__
113		-	while curr is not root and curr.expire < time:
	113	+	while curr is not root and not (time < curr.expire):
114	114		cache_delitem(self, curr.key)
115	115		del links[curr.key]
116	116		next = curr.next

The check that tells the two apart

fail→pass·tests/test_ttl.py::TTLCacheTest::test_ttl

Check file tests/test_ttl.py, taken without changes from the fix and copied onto the older code, so the exact same check runs against both versions.

Origin and history

The fix91aa4c63f5716d8717ee2f898a01f40ce26986ae

The code before it4d11ef92d57e9d838e9160cb5c023baff099c60a

Broken version dated2021-12-18

Modulecachetools.__init__

Units changedTTLCache

Fingerprint769efe841cd73a9f

Checked2026-08-17 by goldset/0.1

Every field above is generated by our program. None of it is written by hand.

Other bugs found in tkem/cachetools

2026-07-22TLRUCache
2026-03-08Fix #218: Fix and properly document @cachedmethod.cache_key handling.
2026-03-05_DescriptorBase
2024-08-18Fix #292, fix #205, fix #103: TTLCache.expire() returns iterable of expired (key, value) pairs.
2024-07-15mru_cache
2021-12-21Fix #159: Pass self to @cachedmethod key function.