From 6b61060b51970bd170fffd442df0e9f02ddcf678 Mon Sep 17 00:00:00 2001 From: Erik Johnston Date: Thu, 2 Feb 2017 14:47:15 +0000 Subject: [PATCH] Comment --- synapse/util/caches/descriptors.py | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/synapse/util/caches/descriptors.py b/synapse/util/caches/descriptors.py index 3c6838df16..998de70d29 100644 --- a/synapse/util/caches/descriptors.py +++ b/synapse/util/caches/descriptors.py @@ -479,7 +479,10 @@ class CacheListDescriptor(object): class _CacheContext(namedtuple("_CacheContext", ("cache", "key"))): # We rely on _CacheContext implementing __eq__ and __hash__ sensibly, - # which namedtuple does for us. + # which namedtuple does for us (i.e. two _CacheContext are the same if + # their caches and keys match). This is important in particular to + # dedupe when we add callbacks to lru cache nodes, otherwise the number + # of callbacks would grow. def invalidate(self): self.cache.invalidate(self.key)