tree ffb1fe015e1dc0665dd39c865d2a08669e731d15
parent 864af5edd3d30290d23b5915387b7d57de74f0c9
author Patrick Hiesel <hiesel@google.com> 1566225260 +0200
committer Patrick Hiesel <hiesel@google.com> 1566226301 +0200

AccountCacheImpl: Stop caching negative results

It's generally a bad practice to cache negative lookup states. In this
case it can lead to strange behavior in case Gerrit misses an
account eviction event. The account cache is in-memory-only, so the
effect is rather limited, but it's a hard-to-debug issue.

When using blame and git history, it seems that there was no special
reason that we cache an Optional here (such as performance) but that
this was a leftover from the migration from Gerrit's hand-grown caches
to Guava caches.

This commit rewrites the logic in AccountCacheImpl to cache an
AccountState instead of an Optional<AccountState>. The API contract
remains unchanged.

Change-Id: Ic5e9c7d90312ff6e32175214d2845335d163fedf