Most recent changelogs are removed first

[francesmcmullin]

Describe the bug
When changelog history is restricted using max_history, the most recent entries are removed instead of older ones.

Expected behavior
The oldest changelog entries should be removed, so I can review for e.g., the 1,000 most recent entries.

Current behavior
Changelog entries are removed most recent first. Here's the relevant line:

sidekiq-unique-jobs/lib/sidekiq_unique_jobs/lua/shared/_common.lua

Line 34 in 8e94cd3

local removed_entries = redis.call("ZREMRANGEBYRANK", changelog, max_history, -1)

Note, this removes entries from "start" of max_history, to -1, or the "end" of the sorted set. From the redis docs on ZREMRANGEBYRANK: "start and stop are 0 -based indexes with 0 being the element with the lowest score", and the score used a few lines above is the current time, so newer entries have higher scores.

Additional context
I recommend inverting the removal, this should work:

  local removed_entries = redis.call("ZREMRANGEBYRANK", changelog, 0, -1 * max_history)