Fix multiple boosts of a same toot erroneously appearing in TL (#14759)

* Check for and record reblog info atomically

Instead of using ZREVRANK to determine whether a reblog is a new reblog or not,
use ZADD's NX option to perform the check/addition option atomically.

* Replace ZREVRANK call with ZSCORE key which is more efficient

* Make tests a bit stricter

* Fix off-by-one
pull/14761/head
ThibG 2020-09-07 18:00:15 +02:00 committed by GitHub
parent e79d719e92
commit 517af45e32
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2 changed files with 11 additions and 13 deletions

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@ -77,9 +77,11 @@ class FeedManager
# Get the score of the REBLOG_FALLOFF'th item in our feed, and stop
# tracking anything after it for deduplication purposes.
falloff_rank = FeedManager::REBLOG_FALLOFF - 1
falloff_rank = FeedManager::REBLOG_FALLOFF
falloff_range = redis.zrevrange(timeline_key, falloff_rank, falloff_rank, with_scores: true)
falloff_score = falloff_range&.first&.last&.to_i || 0
falloff_score = falloff_range&.first&.last&.to_i
return if falloff_score.nil?
# Get any reblogs we might have to clean up after.
redis.zrangebyscore(reblog_key, 0, falloff_score).each do |reblogged_id|
@ -279,14 +281,12 @@ class FeedManager
return false if !rank.nil? && rank < FeedManager::REBLOG_FALLOFF
reblog_rank = redis.zrevrank(reblog_key, status.reblog_of_id)
if reblog_rank.nil?
# The ordered set at `reblog_key` holds statuses which have a reblog
# in the top `REBLOG_FALLOFF` statuses of the timeline
if redis.zadd(reblog_key, status.id, status.reblog_of_id, nx: true)
# This is not something we've already seen reblogged, so we
# can just add it to the feed (and note that we're
# reblogging it).
# can just add it to the feed (and note that we're reblogging it).
redis.zadd(timeline_key, status.id, status.id)
redis.zadd(reblog_key, status.id, status.reblog_of_id)
else
# Another reblog of the same status was already in the
# REBLOG_FALLOFF most recent statuses, so we note that this
@ -300,9 +300,7 @@ class FeedManager
# delay of the worker deliverying the original status, the late addition
# by merging timelines, and other reasons.
# If such a reblog already exists, just do not re-insert it into the feed.
rank = redis.zrevrank(reblog_key, status.id)
return false unless rank.nil?
return false unless redis.zscore(reblog_key, status.id).nil?
redis.zadd(timeline_key, status.id, status.id)
end

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@ -444,8 +444,8 @@ RSpec.describe FeedManager do
expect(Redis.current.exists?(reblog_set_key)).to be true
expect(Redis.current.zrange(reblogs_key, 0, -1)).to eq [reblogged.id.to_s]
# Push everything off the end of the feed.
FeedManager::MAX_ITEMS.times do
# Push everything past the reblog falloff.
FeedManager::REBLOG_FALLOFF.times do
FeedManager.instance.push_to_home(receiver, Fabricate(:status))
end